diff --git a/packages/eslint-plugin-react-hooks/__tests__/ESLintRulesOfHooks-test.js b/packages/eslint-plugin-react-hooks/__tests__/ESLintRulesOfHooks-test.js index b8ec97678aa16..22d2427de69d3 100644 --- a/packages/eslint-plugin-react-hooks/__tests__/ESLintRulesOfHooks-test.js +++ b/packages/eslint-plugin-react-hooks/__tests__/ESLintRulesOfHooks-test.js @@ -34,7 +34,7 @@ function normalizeIndent(strings) { // } // *************************************************** -const tests = { +const allTests = { valid: [ { code: normalizeIndent` @@ -44,6 +44,25 @@ const tests = { } `, }, + { + syntax: 'flow', + code: normalizeIndent` + // Component syntax + component Button() { + useHook(); + return
Button!
; + } + `, + }, + { + syntax: 'flow', + code: normalizeIndent` + // Hook syntax + hook useSampleHook() { + useHook(); + } + `, + }, { code: normalizeIndent` // Valid because components can use hooks. @@ -563,6 +582,28 @@ const tests = { }, ], invalid: [ + { + syntax: 'flow', + code: normalizeIndent` + component Button(cond: boolean) { + if (cond) { + useConditionalHook(); + } + } + `, + errors: [conditionalError('useConditionalHook')], + }, + { + syntax: 'flow', + code: normalizeIndent` + hook useTest(cond: boolean) { + if (cond) { + useConditionalHook(); + } + } + `, + errors: [conditionalError('useConditionalHook')], + }, { code: normalizeIndent` // Invalid because it's dangerous and might not warn otherwise. @@ -1287,8 +1328,8 @@ const tests = { }; if (__EXPERIMENTAL__) { - tests.valid = [ - ...tests.valid, + allTests.valid = [ + ...allTests.valid, { code: normalizeIndent` // Valid because functions created with useEffectEvent can be called in a useEffect. @@ -1385,8 +1426,8 @@ if (__EXPERIMENTAL__) { `, }, ]; - tests.invalid = [ - ...tests.invalid, + allTests.invalid = [ + ...allTests.invalid, { code: normalizeIndent` function MyComponent({ theme }) { @@ -1536,7 +1577,7 @@ function asyncComponentHookError(fn) { if (!process.env.CI) { let only = []; let skipped = []; - [...tests.valid, ...tests.invalid].forEach(t => { + [...allTests.valid, ...allTests.invalid].forEach(t => { if (t.skip) { delete t.skip; skipped.push(t); @@ -1555,10 +1596,23 @@ if (!process.env.CI) { } return true; }; - tests.valid = tests.valid.filter(predicate); - tests.invalid = tests.invalid.filter(predicate); + allTests.valid = allTests.valid.filter(predicate); + allTests.invalid = allTests.invalid.filter(predicate); +} + +function filteredTests(predicate) { + return { + valid: allTests.valid.filter(predicate), + invalid: allTests.invalid.filter(predicate), + }; } +const flowTests = filteredTests(t => t.syntax == null || t.syntax === 'flow'); +const tests = filteredTests(t => t.syntax !== 'flow'); + +allTests.valid.forEach(t => delete t.syntax); +allTests.invalid.forEach(t => delete t.syntax); + describe('rules-of-hooks/rules-of-hooks', () => { const parserOptionsV7 = { ecmaFeatures: { @@ -1594,6 +1648,25 @@ describe('rules-of-hooks/rules-of-hooks', () => { tests ); + new ESLintTesterV7({ + parser: require.resolve('hermes-eslint'), + parserOptions: { + sourceType: 'module', + enableExperimentalComponentSyntax: true, + }, + }).run('eslint: v7, parser: hermes-eslint', ReactHooksESLintRule, flowTests); + + new ESLintTesterV9({ + languageOptions: { + ...languageOptionsV9, + parser: require('hermes-eslint'), + parserOptions: { + sourceType: 'module', + enableExperimentalComponentSyntax: true, + }, + }, + }).run('eslint: v9, parser: hermes-eslint', ReactHooksESLintRule, flowTests); + new ESLintTesterV7({ parser: require.resolve('@typescript-eslint/parser-v2'), parserOptions: parserOptionsV7, diff --git a/packages/eslint-plugin-react-hooks/src/code-path-analysis/LICENSE b/packages/eslint-plugin-react-hooks/src/code-path-analysis/LICENSE new file mode 100644 index 0000000000000..b607bb36e96c3 --- /dev/null +++ b/packages/eslint-plugin-react-hooks/src/code-path-analysis/LICENSE @@ -0,0 +1,19 @@ +Copyright OpenJS Foundation and other contributors, + +Permission is hereby granted, free of charge, to any person obtaining a copy +of this software and associated documentation files (the "Software"), to deal +in the Software without restriction, including without limitation the rights +to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +copies of the Software, and to permit persons to whom the Software is +furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in +all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +THE SOFTWARE. diff --git a/packages/eslint-plugin-react-hooks/src/code-path-analysis/README.md b/packages/eslint-plugin-react-hooks/src/code-path-analysis/README.md new file mode 100644 index 0000000000000..1109cb2f387eb --- /dev/null +++ b/packages/eslint-plugin-react-hooks/src/code-path-analysis/README.md @@ -0,0 +1,6 @@ +# Code Path Analyzer + +This code is a forked version of ESLints Code Path Analyzer which includes +support for Component Syntax. + +Forked from: https://github.com/eslint/eslint/tree/main/lib/linter/code-path-analysis diff --git a/packages/eslint-plugin-react-hooks/src/code-path-analysis/assert.js b/packages/eslint-plugin-react-hooks/src/code-path-analysis/assert.js new file mode 100644 index 0000000000000..d6dc3539f3ad8 --- /dev/null +++ b/packages/eslint-plugin-react-hooks/src/code-path-analysis/assert.js @@ -0,0 +1,9 @@ +'use strict'; + +function assert(cond) { + if (!cond) { + throw new Error('Assertion violated.'); + } +} + +module.exports = assert; diff --git a/packages/eslint-plugin-react-hooks/src/code-path-analysis/code-path-analyzer.js b/packages/eslint-plugin-react-hooks/src/code-path-analysis/code-path-analyzer.js new file mode 100644 index 0000000000000..8dd76e57129b5 --- /dev/null +++ b/packages/eslint-plugin-react-hooks/src/code-path-analysis/code-path-analyzer.js @@ -0,0 +1,802 @@ +'use strict'; + +/* eslint-disable react-internal/no-primitive-constructors */ + +//------------------------------------------------------------------------------ +// Requirements +//------------------------------------------------------------------------------ + +// eslint-disable-next-line +const assert = require('./assert'); +// eslint-disable-next-line +const CodePath = require('./code-path'); +// eslint-disable-next-line +const CodePathSegment = require('./code-path-segment'); +// eslint-disable-next-line +const IdGenerator = require('./id-generator'); + +const breakableTypePattern = + /^(?:(?:Do)?While|For(?:In|Of)?|Switch)Statement$/u; + +//------------------------------------------------------------------------------ +// Helpers +//------------------------------------------------------------------------------ + +/** + * Checks whether or not a given node is a `case` node (not `default` node). + * @param {ASTNode} node A `SwitchCase` node to check. + * @returns {boolean} `true` if the node is a `case` node (not `default` node). + */ +function isCaseNode(node) { + return Boolean(node.test); +} + +/** + * Checks if a given node appears as the value of a PropertyDefinition node. + * @param {ASTNode} node THe node to check. + * @returns {boolean} `true` if the node is a PropertyDefinition value, + * false if not. + */ +function isPropertyDefinitionValue(node) { + const parent = node.parent; + + return ( + parent && parent.type === 'PropertyDefinition' && parent.value === node + ); +} + +/** + * Checks whether the given logical operator is taken into account for the code + * path analysis. + * @param {string} operator The operator found in the LogicalExpression node + * @returns {boolean} `true` if the operator is "&&" or "||" or "??" + */ +function isHandledLogicalOperator(operator) { + return operator === '&&' || operator === '||' || operator === '??'; +} + +/** + * Checks whether the given assignment operator is a logical assignment operator. + * Logical assignments are taken into account for the code path analysis + * because of their short-circuiting semantics. + * @param {string} operator The operator found in the AssignmentExpression node + * @returns {boolean} `true` if the operator is "&&=" or "||=" or "??=" + */ +function isLogicalAssignmentOperator(operator) { + return operator === '&&=' || operator === '||=' || operator === '??='; +} + +/** + * Gets the label if the parent node of a given node is a LabeledStatement. + * @param {ASTNode} node A node to get. + * @returns {string|null} The label or `null`. + */ +function getLabel(node) { + if (node.parent.type === 'LabeledStatement') { + return node.parent.label.name; + } + return null; +} + +/** + * Checks whether or not a given logical expression node goes different path + * between the `true` case and the `false` case. + * @param {ASTNode} node A node to check. + * @returns {boolean} `true` if the node is a test of a choice statement. + */ +function isForkingByTrueOrFalse(node) { + const parent = node.parent; + + switch (parent.type) { + case 'ConditionalExpression': + case 'IfStatement': + case 'WhileStatement': + case 'DoWhileStatement': + case 'ForStatement': + return parent.test === node; + + case 'LogicalExpression': + return isHandledLogicalOperator(parent.operator); + + case 'AssignmentExpression': + return isLogicalAssignmentOperator(parent.operator); + + default: + return false; + } +} + +/** + * Gets the boolean value of a given literal node. + * + * This is used to detect infinity loops (e.g. `while (true) {}`). + * Statements preceded by an infinity loop are unreachable if the loop didn't + * have any `break` statement. + * @param {ASTNode} node A node to get. + * @returns {boolean|undefined} a boolean value if the node is a Literal node, + * otherwise `undefined`. + */ +function getBooleanValueIfSimpleConstant(node) { + if (node.type === 'Literal') { + return Boolean(node.value); + } + return void 0; +} + +/** + * Checks that a given identifier node is a reference or not. + * + * This is used to detect the first throwable node in a `try` block. + * @param {ASTNode} node An Identifier node to check. + * @returns {boolean} `true` if the node is a reference. + */ +function isIdentifierReference(node) { + const parent = node.parent; + + switch (parent.type) { + case 'LabeledStatement': + case 'BreakStatement': + case 'ContinueStatement': + case 'ArrayPattern': + case 'RestElement': + case 'ImportSpecifier': + case 'ImportDefaultSpecifier': + case 'ImportNamespaceSpecifier': + case 'CatchClause': + return false; + + case 'FunctionDeclaration': + case 'ComponentDeclaration': + case 'HookDeclaration': + case 'FunctionExpression': + case 'ArrowFunctionExpression': + case 'ClassDeclaration': + case 'ClassExpression': + case 'VariableDeclarator': + return parent.id !== node; + + case 'Property': + case 'PropertyDefinition': + case 'MethodDefinition': + return parent.key !== node || parent.computed || parent.shorthand; + + case 'AssignmentPattern': + return parent.key !== node; + + default: + return true; + } +} + +/** + * Updates the current segment with the head segment. + * This is similar to local branches and tracking branches of git. + * + * To separate the current and the head is in order to not make useless segments. + * + * In this process, both "onCodePathSegmentStart" and "onCodePathSegmentEnd" + * events are fired. + * @param {CodePathAnalyzer} analyzer The instance. + * @param {ASTNode} node The current AST node. + * @returns {void} + */ +function forwardCurrentToHead(analyzer, node) { + const codePath = analyzer.codePath; + const state = CodePath.getState(codePath); + const currentSegments = state.currentSegments; + const headSegments = state.headSegments; + const end = Math.max(currentSegments.length, headSegments.length); + let i, currentSegment, headSegment; + + // Fires leaving events. + for (i = 0; i < end; ++i) { + currentSegment = currentSegments[i]; + headSegment = headSegments[i]; + + if (currentSegment !== headSegment && currentSegment) { + if (currentSegment.reachable) { + analyzer.emitter.emit('onCodePathSegmentEnd', currentSegment, node); + } + } + } + + // Update state. + state.currentSegments = headSegments; + + // Fires entering events. + for (i = 0; i < end; ++i) { + currentSegment = currentSegments[i]; + headSegment = headSegments[i]; + + if (currentSegment !== headSegment && headSegment) { + CodePathSegment.markUsed(headSegment); + if (headSegment.reachable) { + analyzer.emitter.emit('onCodePathSegmentStart', headSegment, node); + } + } + } +} + +/** + * Updates the current segment with empty. + * This is called at the last of functions or the program. + * @param {CodePathAnalyzer} analyzer The instance. + * @param {ASTNode} node The current AST node. + * @returns {void} + */ +function leaveFromCurrentSegment(analyzer, node) { + const state = CodePath.getState(analyzer.codePath); + const currentSegments = state.currentSegments; + + for (let i = 0; i < currentSegments.length; ++i) { + const currentSegment = currentSegments[i]; + if (currentSegment.reachable) { + analyzer.emitter.emit('onCodePathSegmentEnd', currentSegment, node); + } + } + + state.currentSegments = []; +} + +/** + * Updates the code path due to the position of a given node in the parent node + * thereof. + * + * For example, if the node is `parent.consequent`, this creates a fork from the + * current path. + * @param {CodePathAnalyzer} analyzer The instance. + * @param {ASTNode} node The current AST node. + * @returns {void} + */ +function preprocess(analyzer, node) { + const codePath = analyzer.codePath; + const state = CodePath.getState(codePath); + const parent = node.parent; + + switch (parent.type) { + // The `arguments.length == 0` case is in `postprocess` function. + case 'CallExpression': + if ( + parent.optional === true && + parent.arguments.length >= 1 && + parent.arguments[0] === node + ) { + state.makeOptionalRight(); + } + break; + case 'MemberExpression': + if (parent.optional === true && parent.property === node) { + state.makeOptionalRight(); + } + break; + + case 'LogicalExpression': + if (parent.right === node && isHandledLogicalOperator(parent.operator)) { + state.makeLogicalRight(); + } + break; + + case 'AssignmentExpression': + if ( + parent.right === node && + isLogicalAssignmentOperator(parent.operator) + ) { + state.makeLogicalRight(); + } + break; + + case 'ConditionalExpression': + case 'IfStatement': + /* + * Fork if this node is at `consequent`/`alternate`. + * `popForkContext()` exists at `IfStatement:exit` and + * `ConditionalExpression:exit`. + */ + if (parent.consequent === node) { + state.makeIfConsequent(); + } else if (parent.alternate === node) { + state.makeIfAlternate(); + } + break; + + case 'SwitchCase': + if (parent.consequent[0] === node) { + state.makeSwitchCaseBody(false, !parent.test); + } + break; + + case 'TryStatement': + if (parent.handler === node) { + state.makeCatchBlock(); + } else if (parent.finalizer === node) { + state.makeFinallyBlock(); + } + break; + + case 'WhileStatement': + if (parent.test === node) { + state.makeWhileTest(getBooleanValueIfSimpleConstant(node)); + } else { + assert(parent.body === node); + state.makeWhileBody(); + } + break; + + case 'DoWhileStatement': + if (parent.body === node) { + state.makeDoWhileBody(); + } else { + assert(parent.test === node); + state.makeDoWhileTest(getBooleanValueIfSimpleConstant(node)); + } + break; + + case 'ForStatement': + if (parent.test === node) { + state.makeForTest(getBooleanValueIfSimpleConstant(node)); + } else if (parent.update === node) { + state.makeForUpdate(); + } else if (parent.body === node) { + state.makeForBody(); + } + break; + + case 'ForInStatement': + case 'ForOfStatement': + if (parent.left === node) { + state.makeForInOfLeft(); + } else if (parent.right === node) { + state.makeForInOfRight(); + } else { + assert(parent.body === node); + state.makeForInOfBody(); + } + break; + + case 'AssignmentPattern': + /* + * Fork if this node is at `right`. + * `left` is executed always, so it uses the current path. + * `popForkContext()` exists at `AssignmentPattern:exit`. + */ + if (parent.right === node) { + state.pushForkContext(); + state.forkBypassPath(); + state.forkPath(); + } + break; + + default: + break; + } +} + +/** + * Updates the code path due to the type of a given node in entering. + * @param {CodePathAnalyzer} analyzer The instance. + * @param {ASTNode} node The current AST node. + * @returns {void} + */ +function processCodePathToEnter(analyzer, node) { + let codePath = analyzer.codePath; + let state = codePath && CodePath.getState(codePath); + const parent = node.parent; + + /** + * Creates a new code path and trigger the onCodePathStart event + * based on the currently selected node. + * @param {string} origin The reason the code path was started. + * @returns {void} + */ + function startCodePath(origin) { + if (codePath) { + // Emits onCodePathSegmentStart events if updated. + forwardCurrentToHead(analyzer, node); + } + + // Create the code path of this scope. + codePath = analyzer.codePath = new CodePath({ + id: analyzer.idGenerator.next(), + origin, + upper: codePath, + onLooped: analyzer.onLooped, + }); + state = CodePath.getState(codePath); + + // Emits onCodePathStart events. + analyzer.emitter.emit('onCodePathStart', codePath, node); + } + + /* + * Special case: The right side of class field initializer is considered + * to be its own function, so we need to start a new code path in this + * case. + */ + if (isPropertyDefinitionValue(node)) { + startCodePath('class-field-initializer'); + + /* + * Intentional fall through because `node` needs to also be + * processed by the code below. For example, if we have: + * + * class Foo { + * a = () => {} + * } + * + * In this case, we also need start a second code path. + */ + } + + switch (node.type) { + case 'Program': + startCodePath('program'); + break; + + case 'FunctionDeclaration': + case 'ComponentDeclaration': + case 'HookDeclaration': + case 'FunctionExpression': + case 'ArrowFunctionExpression': + startCodePath('function'); + break; + + case 'StaticBlock': + startCodePath('class-static-block'); + break; + + case 'ChainExpression': + state.pushChainContext(); + break; + case 'CallExpression': + if (node.optional === true) { + state.makeOptionalNode(); + } + break; + case 'MemberExpression': + if (node.optional === true) { + state.makeOptionalNode(); + } + break; + + case 'LogicalExpression': + if (isHandledLogicalOperator(node.operator)) { + state.pushChoiceContext(node.operator, isForkingByTrueOrFalse(node)); + } + break; + + case 'AssignmentExpression': + if (isLogicalAssignmentOperator(node.operator)) { + state.pushChoiceContext( + node.operator.slice(0, -1), // removes `=` from the end + isForkingByTrueOrFalse(node), + ); + } + break; + + case 'ConditionalExpression': + case 'IfStatement': + state.pushChoiceContext('test', false); + break; + + case 'SwitchStatement': + state.pushSwitchContext(node.cases.some(isCaseNode), getLabel(node)); + break; + + case 'TryStatement': + state.pushTryContext(Boolean(node.finalizer)); + break; + + case 'SwitchCase': + /* + * Fork if this node is after the 2st node in `cases`. + * It's similar to `else` blocks. + * The next `test` node is processed in this path. + */ + if (parent.discriminant !== node && parent.cases[0] !== node) { + state.forkPath(); + } + break; + + case 'WhileStatement': + case 'DoWhileStatement': + case 'ForStatement': + case 'ForInStatement': + case 'ForOfStatement': + state.pushLoopContext(node.type, getLabel(node)); + break; + + case 'LabeledStatement': + if (!breakableTypePattern.test(node.body.type)) { + state.pushBreakContext(false, node.label.name); + } + break; + + default: + break; + } + + // Emits onCodePathSegmentStart events if updated. + forwardCurrentToHead(analyzer, node); +} + +/** + * Updates the code path due to the type of a given node in leaving. + * @param {CodePathAnalyzer} analyzer The instance. + * @param {ASTNode} node The current AST node. + * @returns {void} + */ +function processCodePathToExit(analyzer, node) { + const codePath = analyzer.codePath; + const state = CodePath.getState(codePath); + let dontForward = false; + + switch (node.type) { + case 'ChainExpression': + state.popChainContext(); + break; + + case 'IfStatement': + case 'ConditionalExpression': + state.popChoiceContext(); + break; + + case 'LogicalExpression': + if (isHandledLogicalOperator(node.operator)) { + state.popChoiceContext(); + } + break; + + case 'AssignmentExpression': + if (isLogicalAssignmentOperator(node.operator)) { + state.popChoiceContext(); + } + break; + + case 'SwitchStatement': + state.popSwitchContext(); + break; + + case 'SwitchCase': + /* + * This is the same as the process at the 1st `consequent` node in + * `preprocess` function. + * Must do if this `consequent` is empty. + */ + if (node.consequent.length === 0) { + state.makeSwitchCaseBody(true, !node.test); + } + if (state.forkContext.reachable) { + dontForward = true; + } + break; + + case 'TryStatement': + state.popTryContext(); + break; + + case 'BreakStatement': + forwardCurrentToHead(analyzer, node); + state.makeBreak(node.label && node.label.name); + dontForward = true; + break; + + case 'ContinueStatement': + forwardCurrentToHead(analyzer, node); + state.makeContinue(node.label && node.label.name); + dontForward = true; + break; + + case 'ReturnStatement': + forwardCurrentToHead(analyzer, node); + state.makeReturn(); + dontForward = true; + break; + + case 'ThrowStatement': + forwardCurrentToHead(analyzer, node); + state.makeThrow(); + dontForward = true; + break; + + case 'Identifier': + if (isIdentifierReference(node)) { + state.makeFirstThrowablePathInTryBlock(); + dontForward = true; + } + break; + + case 'CallExpression': + case 'ImportExpression': + case 'MemberExpression': + case 'NewExpression': + case 'YieldExpression': + state.makeFirstThrowablePathInTryBlock(); + break; + + case 'WhileStatement': + case 'DoWhileStatement': + case 'ForStatement': + case 'ForInStatement': + case 'ForOfStatement': + state.popLoopContext(); + break; + + case 'AssignmentPattern': + state.popForkContext(); + break; + + case 'LabeledStatement': + if (!breakableTypePattern.test(node.body.type)) { + state.popBreakContext(); + } + break; + + default: + break; + } + + // Emits onCodePathSegmentStart events if updated. + if (!dontForward) { + forwardCurrentToHead(analyzer, node); + } +} + +/** + * Updates the code path to finalize the current code path. + * @param {CodePathAnalyzer} analyzer The instance. + * @param {ASTNode} node The current AST node. + * @returns {void} + */ +function postprocess(analyzer, node) { + /** + * Ends the code path for the current node. + * @returns {void} + */ + function endCodePath() { + let codePath = analyzer.codePath; + + // Mark the current path as the final node. + CodePath.getState(codePath).makeFinal(); + + // Emits onCodePathSegmentEnd event of the current segments. + leaveFromCurrentSegment(analyzer, node); + + // Emits onCodePathEnd event of this code path. + analyzer.emitter.emit('onCodePathEnd', codePath, node); + + codePath = analyzer.codePath = analyzer.codePath.upper; + } + + switch (node.type) { + case 'Program': + case 'FunctionDeclaration': + case 'ComponentDeclaration': + case 'HookDeclaration': + case 'FunctionExpression': + case 'ArrowFunctionExpression': + case 'StaticBlock': { + endCodePath(); + break; + } + + // The `arguments.length >= 1` case is in `preprocess` function. + case 'CallExpression': + if (node.optional === true && node.arguments.length === 0) { + CodePath.getState(analyzer.codePath).makeOptionalRight(); + } + break; + + default: + break; + } + + /* + * Special case: The right side of class field initializer is considered + * to be its own function, so we need to end a code path in this + * case. + * + * We need to check after the other checks in order to close the + * code paths in the correct order for code like this: + * + * + * class Foo { + * a = () => {} + * } + * + * In this case, The ArrowFunctionExpression code path is closed first + * and then we need to close the code path for the PropertyDefinition + * value. + */ + if (isPropertyDefinitionValue(node)) { + endCodePath(); + } +} + +//------------------------------------------------------------------------------ +// Public Interface +//------------------------------------------------------------------------------ + +/** + * The class to analyze code paths. + * This class implements the EventGenerator interface. + */ +class CodePathAnalyzer { + /** + * @param {EventGenerator} eventGenerator An event generator to wrap. + */ + constructor(emitters) { + this.emitter = { + emit(event, ...args) { + emitters[event]?.(...args); + }, + }; + this.codePath = null; + this.idGenerator = new IdGenerator('s'); + this.currentNode = null; + this.onLooped = this.onLooped.bind(this); + } + + /** + * Does the process to enter a given AST node. + * This updates state of analysis and calls `enterNode` of the wrapped. + * @param {ASTNode} node A node which is entering. + * @returns {void} + */ + enterNode(node) { + this.currentNode = node; + + // Updates the code path due to node's position in its parent node. + if (node.parent) { + preprocess(this, node); + } + + /* + * Updates the code path. + * And emits onCodePathStart/onCodePathSegmentStart events. + */ + processCodePathToEnter(this, node); + + this.currentNode = null; + } + + /** + * Does the process to leave a given AST node. + * This updates state of analysis and calls `leaveNode` of the wrapped. + * @param {ASTNode} node A node which is leaving. + * @returns {void} + */ + leaveNode(node) { + this.currentNode = node; + + /* + * Updates the code path. + * And emits onCodePathStart/onCodePathSegmentStart events. + */ + processCodePathToExit(this, node); + + // Emits the last onCodePathStart/onCodePathSegmentStart events. + postprocess(this, node); + + this.currentNode = null; + } + + /** + * This is called on a code path looped. + * Then this raises a looped event. + * @param {CodePathSegment} fromSegment A segment of prev. + * @param {CodePathSegment} toSegment A segment of next. + * @returns {void} + */ + onLooped(fromSegment, toSegment) { + if (fromSegment.reachable && toSegment.reachable) { + this.emitter.emit( + 'onCodePathSegmentLoop', + fromSegment, + toSegment, + this.currentNode, + ); + } + } +} + +module.exports = CodePathAnalyzer; diff --git a/packages/eslint-plugin-react-hooks/src/code-path-analysis/code-path-segment.js b/packages/eslint-plugin-react-hooks/src/code-path-analysis/code-path-segment.js new file mode 100644 index 0000000000000..fb015296a74fb --- /dev/null +++ b/packages/eslint-plugin-react-hooks/src/code-path-analysis/code-path-segment.js @@ -0,0 +1,225 @@ +'use strict'; + +//------------------------------------------------------------------------------ +// Requirements +//------------------------------------------------------------------------------ + +//------------------------------------------------------------------------------ +// Helpers +//------------------------------------------------------------------------------ + +/** + * Checks whether or not a given segment is reachable. + * @param {CodePathSegment} segment A segment to check. + * @returns {boolean} `true` if the segment is reachable. + */ +function isReachable(segment) { + return segment.reachable; +} + +//------------------------------------------------------------------------------ +// Public Interface +//------------------------------------------------------------------------------ + +/** + * A code path segment. + */ +class CodePathSegment { + /** + * @param {string} id An identifier. + * @param {CodePathSegment[]} allPrevSegments An array of the previous segments. + * This array includes unreachable segments. + * @param {boolean} reachable A flag which shows this is reachable. + */ + constructor(id, allPrevSegments, reachable) { + /** + * The identifier of this code path. + * Rules use it to store additional information of each rule. + * @type {string} + */ + this.id = id; + + /** + * An array of the next segments. + * @type {CodePathSegment[]} + */ + this.nextSegments = []; + + /** + * An array of the previous segments. + * @type {CodePathSegment[]} + */ + this.prevSegments = allPrevSegments.filter(isReachable); + + /** + * An array of the next segments. + * This array includes unreachable segments. + * @type {CodePathSegment[]} + */ + this.allNextSegments = []; + + /** + * An array of the previous segments. + * This array includes unreachable segments. + * @type {CodePathSegment[]} + */ + this.allPrevSegments = allPrevSegments; + + /** + * A flag which shows this is reachable. + * @type {boolean} + */ + this.reachable = reachable; + + // Internal data. + Object.defineProperty(this, 'internal', { + value: { + used: false, + loopedPrevSegments: [], + }, + }); + } + + /** + * Checks a given previous segment is coming from the end of a loop. + * @param {CodePathSegment} segment A previous segment to check. + * @returns {boolean} `true` if the segment is coming from the end of a loop. + */ + isLoopedPrevSegment(segment) { + return this.internal.loopedPrevSegments.includes(segment); + } + + /** + * Creates the root segment. + * @param {string} id An identifier. + * @returns {CodePathSegment} The created segment. + */ + static newRoot(id) { + return new CodePathSegment(id, [], true); + } + + /** + * Creates a segment that follows given segments. + * @param {string} id An identifier. + * @param {CodePathSegment[]} allPrevSegments An array of the previous segments. + * @returns {CodePathSegment} The created segment. + */ + static newNext(id, allPrevSegments) { + return new CodePathSegment( + id, + CodePathSegment.flattenUnusedSegments(allPrevSegments), + allPrevSegments.some(isReachable), + ); + } + + /** + * Creates an unreachable segment that follows given segments. + * @param {string} id An identifier. + * @param {CodePathSegment[]} allPrevSegments An array of the previous segments. + * @returns {CodePathSegment} The created segment. + */ + static newUnreachable(id, allPrevSegments) { + const segment = new CodePathSegment( + id, + CodePathSegment.flattenUnusedSegments(allPrevSegments), + false, + ); + + /* + * In `if (a) return a; foo();` case, the unreachable segment preceded by + * the return statement is not used but must not be remove. + */ + CodePathSegment.markUsed(segment); + + return segment; + } + + /** + * Creates a segment that follows given segments. + * This factory method does not connect with `allPrevSegments`. + * But this inherits `reachable` flag. + * @param {string} id An identifier. + * @param {CodePathSegment[]} allPrevSegments An array of the previous segments. + * @returns {CodePathSegment} The created segment. + */ + static newDisconnected(id, allPrevSegments) { + return new CodePathSegment(id, [], allPrevSegments.some(isReachable)); + } + + /** + * Makes a given segment being used. + * + * And this function registers the segment into the previous segments as a next. + * @param {CodePathSegment} segment A segment to mark. + * @returns {void} + */ + static markUsed(segment) { + if (segment.internal.used) { + return; + } + segment.internal.used = true; + + let i; + + if (segment.reachable) { + for (i = 0; i < segment.allPrevSegments.length; ++i) { + const prevSegment = segment.allPrevSegments[i]; + + prevSegment.allNextSegments.push(segment); + prevSegment.nextSegments.push(segment); + } + } else { + for (i = 0; i < segment.allPrevSegments.length; ++i) { + segment.allPrevSegments[i].allNextSegments.push(segment); + } + } + } + + /** + * Marks a previous segment as looped. + * @param {CodePathSegment} segment A segment. + * @param {CodePathSegment} prevSegment A previous segment to mark. + * @returns {void} + */ + static markPrevSegmentAsLooped(segment, prevSegment) { + segment.internal.loopedPrevSegments.push(prevSegment); + } + + /** + * Replaces unused segments with the previous segments of each unused segment. + * @param {CodePathSegment[]} segments An array of segments to replace. + * @returns {CodePathSegment[]} The replaced array. + */ + static flattenUnusedSegments(segments) { + const done = Object.create(null); + const retv = []; + + for (let i = 0; i < segments.length; ++i) { + const segment = segments[i]; + + // Ignores duplicated. + if (done[segment.id]) { + continue; + } + + // Use previous segments if unused. + if (!segment.internal.used) { + for (let j = 0; j < segment.allPrevSegments.length; ++j) { + const prevSegment = segment.allPrevSegments[j]; + + if (!done[prevSegment.id]) { + done[prevSegment.id] = true; + retv.push(prevSegment); + } + } + } else { + done[segment.id] = true; + retv.push(segment); + } + } + + return retv; + } +} + +module.exports = CodePathSegment; diff --git a/packages/eslint-plugin-react-hooks/src/code-path-analysis/code-path-state.js b/packages/eslint-plugin-react-hooks/src/code-path-analysis/code-path-state.js new file mode 100644 index 0000000000000..9a107fecd7f9c --- /dev/null +++ b/packages/eslint-plugin-react-hooks/src/code-path-analysis/code-path-state.js @@ -0,0 +1,1441 @@ +'use strict'; + +//------------------------------------------------------------------------------ +// Requirements +//------------------------------------------------------------------------------ + +// eslint-disable-next-line +const CodePathSegment = require('./code-path-segment'); +// eslint-disable-next-line +const ForkContext = require('./fork-context'); + +//------------------------------------------------------------------------------ +// Helpers +//------------------------------------------------------------------------------ + +/** + * Adds given segments into the `dest` array. + * If the `others` array does not includes the given segments, adds to the `all` + * array as well. + * + * This adds only reachable and used segments. + * @param {CodePathSegment[]} dest A destination array (`returnedSegments` or `thrownSegments`). + * @param {CodePathSegment[]} others Another destination array (`returnedSegments` or `thrownSegments`). + * @param {CodePathSegment[]} all The unified destination array (`finalSegments`). + * @param {CodePathSegment[]} segments Segments to add. + * @returns {void} + */ +function addToReturnedOrThrown(dest, others, all, segments) { + for (let i = 0; i < segments.length; ++i) { + const segment = segments[i]; + + dest.push(segment); + if (!others.includes(segment)) { + all.push(segment); + } + } +} + +/** + * Gets a loop-context for a `continue` statement. + * @param {CodePathState} state A state to get. + * @param {string} label The label of a `continue` statement. + * @returns {LoopContext} A loop-context for a `continue` statement. + */ +function getContinueContext(state, label) { + if (!label) { + return state.loopContext; + } + + let context = state.loopContext; + + while (context) { + if (context.label === label) { + return context; + } + context = context.upper; + } + + /* c8 ignore next */ + return null; +} + +/** + * Gets a context for a `break` statement. + * @param {CodePathState} state A state to get. + * @param {string} label The label of a `break` statement. + * @returns {LoopContext|SwitchContext} A context for a `break` statement. + */ +function getBreakContext(state, label) { + let context = state.breakContext; + + while (context) { + if (label ? context.label === label : context.breakable) { + return context; + } + context = context.upper; + } + + /* c8 ignore next */ + return null; +} + +/** + * Gets a context for a `return` statement. + * @param {CodePathState} state A state to get. + * @returns {TryContext|CodePathState} A context for a `return` statement. + */ +function getReturnContext(state) { + let context = state.tryContext; + + while (context) { + if (context.hasFinalizer && context.position !== 'finally') { + return context; + } + context = context.upper; + } + + return state; +} + +/** + * Gets a context for a `throw` statement. + * @param {CodePathState} state A state to get. + * @returns {TryContext|CodePathState} A context for a `throw` statement. + */ +function getThrowContext(state) { + let context = state.tryContext; + + while (context) { + if ( + context.position === 'try' || + (context.hasFinalizer && context.position === 'catch') + ) { + return context; + } + context = context.upper; + } + + return state; +} + +/** + * Removes a given element from a given array. + * @param {any[]} xs An array to remove the specific element. + * @param {any} x An element to be removed. + * @returns {void} + */ +function remove(xs, x) { + xs.splice(xs.indexOf(x), 1); +} + +/** + * Disconnect given segments. + * + * This is used in a process for switch statements. + * If there is the "default" chunk before other cases, the order is different + * between node's and running's. + * @param {CodePathSegment[]} prevSegments Forward segments to disconnect. + * @param {CodePathSegment[]} nextSegments Backward segments to disconnect. + * @returns {void} + */ +function removeConnection(prevSegments, nextSegments) { + for (let i = 0; i < prevSegments.length; ++i) { + const prevSegment = prevSegments[i]; + const nextSegment = nextSegments[i]; + + remove(prevSegment.nextSegments, nextSegment); + remove(prevSegment.allNextSegments, nextSegment); + remove(nextSegment.prevSegments, prevSegment); + remove(nextSegment.allPrevSegments, prevSegment); + } +} + +/** + * Creates looping path. + * @param {CodePathState} state The instance. + * @param {CodePathSegment[]} unflattenedFromSegments Segments which are source. + * @param {CodePathSegment[]} unflattenedToSegments Segments which are destination. + * @returns {void} + */ +function makeLooped(state, unflattenedFromSegments, unflattenedToSegments) { + const fromSegments = CodePathSegment.flattenUnusedSegments( + unflattenedFromSegments, + ); + const toSegments = CodePathSegment.flattenUnusedSegments( + unflattenedToSegments, + ); + + const end = Math.min(fromSegments.length, toSegments.length); + + for (let i = 0; i < end; ++i) { + const fromSegment = fromSegments[i]; + const toSegment = toSegments[i]; + + if (toSegment.reachable) { + fromSegment.nextSegments.push(toSegment); + } + if (fromSegment.reachable) { + toSegment.prevSegments.push(fromSegment); + } + fromSegment.allNextSegments.push(toSegment); + toSegment.allPrevSegments.push(fromSegment); + + if (toSegment.allPrevSegments.length >= 2) { + CodePathSegment.markPrevSegmentAsLooped(toSegment, fromSegment); + } + + state.notifyLooped(fromSegment, toSegment); + } +} + +/** + * Finalizes segments of `test` chunk of a ForStatement. + * + * - Adds `false` paths to paths which are leaving from the loop. + * - Sets `true` paths to paths which go to the body. + * @param {LoopContext} context A loop context to modify. + * @param {ChoiceContext} choiceContext A choice context of this loop. + * @param {CodePathSegment[]} head The current head paths. + * @returns {void} + */ +function finalizeTestSegmentsOfFor(context, choiceContext, head) { + if (!choiceContext.processed) { + choiceContext.trueForkContext.add(head); + choiceContext.falseForkContext.add(head); + choiceContext.qqForkContext.add(head); + } + + if (context.test !== true) { + context.brokenForkContext.addAll(choiceContext.falseForkContext); + } + context.endOfTestSegments = choiceContext.trueForkContext.makeNext(0, -1); +} + +//------------------------------------------------------------------------------ +// Public Interface +//------------------------------------------------------------------------------ + +/** + * A class which manages state to analyze code paths. + */ +class CodePathState { + /** + * @param {IdGenerator} idGenerator An id generator to generate id for code + * path segments. + * @param {Function} onLooped A callback function to notify looping. + */ + constructor(idGenerator, onLooped) { + this.idGenerator = idGenerator; + this.notifyLooped = onLooped; + this.forkContext = ForkContext.newRoot(idGenerator); + this.choiceContext = null; + this.switchContext = null; + this.tryContext = null; + this.loopContext = null; + this.breakContext = null; + this.chainContext = null; + + this.currentSegments = []; + this.initialSegment = this.forkContext.head[0]; + + // returnedSegments and thrownSegments push elements into finalSegments also. + const final = (this.finalSegments = []); + const returned = (this.returnedForkContext = []); + const thrown = (this.thrownForkContext = []); + + returned.add = addToReturnedOrThrown.bind(null, returned, thrown, final); + thrown.add = addToReturnedOrThrown.bind(null, thrown, returned, final); + } + + /** + * The head segments. + * @type {CodePathSegment[]} + */ + get headSegments() { + return this.forkContext.head; + } + + /** + * The parent forking context. + * This is used for the root of new forks. + * @type {ForkContext} + */ + get parentForkContext() { + const current = this.forkContext; + + return current && current.upper; + } + + /** + * Creates and stacks new forking context. + * @param {boolean} forkLeavingPath A flag which shows being in a + * "finally" block. + * @returns {ForkContext} The created context. + */ + pushForkContext(forkLeavingPath) { + this.forkContext = ForkContext.newEmpty(this.forkContext, forkLeavingPath); + + return this.forkContext; + } + + /** + * Pops and merges the last forking context. + * @returns {ForkContext} The last context. + */ + popForkContext() { + const lastContext = this.forkContext; + + this.forkContext = lastContext.upper; + this.forkContext.replaceHead(lastContext.makeNext(0, -1)); + + return lastContext; + } + + /** + * Creates a new path. + * @returns {void} + */ + forkPath() { + this.forkContext.add(this.parentForkContext.makeNext(-1, -1)); + } + + /** + * Creates a bypass path. + * This is used for such as IfStatement which does not have "else" chunk. + * @returns {void} + */ + forkBypassPath() { + this.forkContext.add(this.parentForkContext.head); + } + + //-------------------------------------------------------------------------- + // ConditionalExpression, LogicalExpression, IfStatement + //-------------------------------------------------------------------------- + + /** + * Creates a context for ConditionalExpression, LogicalExpression, AssignmentExpression (logical assignments only), + * IfStatement, WhileStatement, DoWhileStatement, or ForStatement. + * + * LogicalExpressions have cases that it goes different paths between the + * `true` case and the `false` case. + * + * For Example: + * + * if (a || b) { + * foo(); + * } else { + * bar(); + * } + * + * In this case, `b` is evaluated always in the code path of the `else` + * block, but it's not so in the code path of the `if` block. + * So there are 3 paths. + * + * a -> foo(); + * a -> b -> foo(); + * a -> b -> bar(); + * @param {string} kind A kind string. + * If the new context is LogicalExpression's or AssignmentExpression's, this is `"&&"` or `"||"` or `"??"`. + * If it's IfStatement's or ConditionalExpression's, this is `"test"`. + * Otherwise, this is `"loop"`. + * @param {boolean} isForkingAsResult A flag that shows that goes different + * paths between `true` and `false`. + * @returns {void} + */ + pushChoiceContext(kind, isForkingAsResult) { + this.choiceContext = { + upper: this.choiceContext, + kind, + isForkingAsResult, + trueForkContext: ForkContext.newEmpty(this.forkContext), + falseForkContext: ForkContext.newEmpty(this.forkContext), + qqForkContext: ForkContext.newEmpty(this.forkContext), + processed: false, + }; + } + + /** + * Pops the last choice context and finalizes it. + * @throws {Error} (Unreachable.) + * @returns {ChoiceContext} The popped context. + */ + popChoiceContext() { + const context = this.choiceContext; + + this.choiceContext = context.upper; + + const forkContext = this.forkContext; + const headSegments = forkContext.head; + + switch (context.kind) { + case '&&': + case '||': + case '??': + /* + * If any result were not transferred from child contexts, + * this sets the head segments to both cases. + * The head segments are the path of the right-hand operand. + */ + if (!context.processed) { + context.trueForkContext.add(headSegments); + context.falseForkContext.add(headSegments); + context.qqForkContext.add(headSegments); + } + + /* + * Transfers results to upper context if this context is in + * test chunk. + */ + if (context.isForkingAsResult) { + const parentContext = this.choiceContext; + + parentContext.trueForkContext.addAll(context.trueForkContext); + parentContext.falseForkContext.addAll(context.falseForkContext); + parentContext.qqForkContext.addAll(context.qqForkContext); + parentContext.processed = true; + + return context; + } + + break; + + case 'test': + if (!context.processed) { + /* + * The head segments are the path of the `if` block here. + * Updates the `true` path with the end of the `if` block. + */ + context.trueForkContext.clear(); + context.trueForkContext.add(headSegments); + } else { + /* + * The head segments are the path of the `else` block here. + * Updates the `false` path with the end of the `else` + * block. + */ + context.falseForkContext.clear(); + context.falseForkContext.add(headSegments); + } + + break; + + case 'loop': + /* + * Loops are addressed in popLoopContext(). + * This is called from popLoopContext(). + */ + return context; + + /* c8 ignore next */ + default: + throw new Error('unreachable'); + } + + // Merges all paths. + const prevForkContext = context.trueForkContext; + + prevForkContext.addAll(context.falseForkContext); + forkContext.replaceHead(prevForkContext.makeNext(0, -1)); + + return context; + } + + /** + * Makes a code path segment of the right-hand operand of a logical + * expression. + * @throws {Error} (Unreachable.) + * @returns {void} + */ + makeLogicalRight() { + const context = this.choiceContext; + const forkContext = this.forkContext; + + if (context.processed) { + /* + * This got segments already from the child choice context. + * Creates the next path from own true/false fork context. + */ + let prevForkContext; + + switch (context.kind) { + case '&&': // if true then go to the right-hand side. + prevForkContext = context.trueForkContext; + break; + case '||': // if false then go to the right-hand side. + prevForkContext = context.falseForkContext; + break; + case '??': // Both true/false can short-circuit, so needs the third path to go to the right-hand side. That's qqForkContext. + prevForkContext = context.qqForkContext; + break; + default: + throw new Error('unreachable'); + } + + forkContext.replaceHead(prevForkContext.makeNext(0, -1)); + prevForkContext.clear(); + context.processed = false; + } else { + /* + * This did not get segments from the child choice context. + * So addresses the head segments. + * The head segments are the path of the left-hand operand. + */ + switch (context.kind) { + case '&&': // the false path can short-circuit. + context.falseForkContext.add(forkContext.head); + break; + case '||': // the true path can short-circuit. + context.trueForkContext.add(forkContext.head); + break; + case '??': // both can short-circuit. + context.trueForkContext.add(forkContext.head); + context.falseForkContext.add(forkContext.head); + break; + default: + throw new Error('unreachable'); + } + + forkContext.replaceHead(forkContext.makeNext(-1, -1)); + } + } + + /** + * Makes a code path segment of the `if` block. + * @returns {void} + */ + makeIfConsequent() { + const context = this.choiceContext; + const forkContext = this.forkContext; + + /* + * If any result were not transferred from child contexts, + * this sets the head segments to both cases. + * The head segments are the path of the test expression. + */ + if (!context.processed) { + context.trueForkContext.add(forkContext.head); + context.falseForkContext.add(forkContext.head); + context.qqForkContext.add(forkContext.head); + } + + context.processed = false; + + // Creates new path from the `true` case. + forkContext.replaceHead(context.trueForkContext.makeNext(0, -1)); + } + + /** + * Makes a code path segment of the `else` block. + * @returns {void} + */ + makeIfAlternate() { + const context = this.choiceContext; + const forkContext = this.forkContext; + + /* + * The head segments are the path of the `if` block. + * Updates the `true` path with the end of the `if` block. + */ + context.trueForkContext.clear(); + context.trueForkContext.add(forkContext.head); + context.processed = true; + + // Creates new path from the `false` case. + forkContext.replaceHead(context.falseForkContext.makeNext(0, -1)); + } + + //-------------------------------------------------------------------------- + // ChainExpression + //-------------------------------------------------------------------------- + + /** + * Push a new `ChainExpression` context to the stack. + * This method is called on entering to each `ChainExpression` node. + * This context is used to count forking in the optional chain then merge them on the exiting from the `ChainExpression` node. + * @returns {void} + */ + pushChainContext() { + this.chainContext = { + upper: this.chainContext, + countChoiceContexts: 0, + }; + } + + /** + * Pop a `ChainExpression` context from the stack. + * This method is called on exiting from each `ChainExpression` node. + * This merges all forks of the last optional chaining. + * @returns {void} + */ + popChainContext() { + const context = this.chainContext; + + this.chainContext = context.upper; + + // pop all choice contexts of this. + for (let i = context.countChoiceContexts; i > 0; --i) { + this.popChoiceContext(); + } + } + + /** + * Create a choice context for optional access. + * This method is called on entering to each `(Call|Member)Expression[optional=true]` node. + * This creates a choice context as similar to `LogicalExpression[operator="??"]` node. + * @returns {void} + */ + makeOptionalNode() { + if (this.chainContext) { + this.chainContext.countChoiceContexts += 1; + this.pushChoiceContext('??', false); + } + } + + /** + * Create a fork. + * This method is called on entering to the `arguments|property` property of each `(Call|Member)Expression` node. + * @returns {void} + */ + makeOptionalRight() { + if (this.chainContext) { + this.makeLogicalRight(); + } + } + + //-------------------------------------------------------------------------- + // SwitchStatement + //-------------------------------------------------------------------------- + + /** + * Creates a context object of SwitchStatement and stacks it. + * @param {boolean} hasCase `true` if the switch statement has one or more + * case parts. + * @param {string|null} label The label text. + * @returns {void} + */ + pushSwitchContext(hasCase, label) { + this.switchContext = { + upper: this.switchContext, + hasCase, + defaultSegments: null, + defaultBodySegments: null, + foundDefault: false, + lastIsDefault: false, + countForks: 0, + }; + + this.pushBreakContext(true, label); + } + + /** + * Pops the last context of SwitchStatement and finalizes it. + * + * - Disposes all forking stack for `case` and `default`. + * - Creates the next code path segment from `context.brokenForkContext`. + * - If the last `SwitchCase` node is not a `default` part, creates a path + * to the `default` body. + * @returns {void} + */ + popSwitchContext() { + const context = this.switchContext; + + this.switchContext = context.upper; + + const forkContext = this.forkContext; + const brokenForkContext = this.popBreakContext().brokenForkContext; + + if (context.countForks === 0) { + /* + * When there is only one `default` chunk and there is one or more + * `break` statements, even if forks are nothing, it needs to merge + * those. + */ + if (!brokenForkContext.empty) { + brokenForkContext.add(forkContext.makeNext(-1, -1)); + forkContext.replaceHead(brokenForkContext.makeNext(0, -1)); + } + + return; + } + + const lastSegments = forkContext.head; + + this.forkBypassPath(); + const lastCaseSegments = forkContext.head; + + /* + * `brokenForkContext` is used to make the next segment. + * It must add the last segment into `brokenForkContext`. + */ + brokenForkContext.add(lastSegments); + + /* + * A path which is failed in all case test should be connected to path + * of `default` chunk. + */ + if (!context.lastIsDefault) { + if (context.defaultBodySegments) { + /* + * Remove a link from `default` label to its chunk. + * It's false route. + */ + removeConnection(context.defaultSegments, context.defaultBodySegments); + makeLooped(this, lastCaseSegments, context.defaultBodySegments); + } else { + /* + * It handles the last case body as broken if `default` chunk + * does not exist. + */ + brokenForkContext.add(lastCaseSegments); + } + } + + // Pops the segment context stack until the entry segment. + for (let i = 0; i < context.countForks; ++i) { + this.forkContext = this.forkContext.upper; + } + + /* + * Creates a path from all brokenForkContext paths. + * This is a path after switch statement. + */ + this.forkContext.replaceHead(brokenForkContext.makeNext(0, -1)); + } + + /** + * Makes a code path segment for a `SwitchCase` node. + * @param {boolean} isEmpty `true` if the body is empty. + * @param {boolean} isDefault `true` if the body is the default case. + * @returns {void} + */ + makeSwitchCaseBody(isEmpty, isDefault) { + const context = this.switchContext; + + if (!context.hasCase) { + return; + } + + /* + * Merge forks. + * The parent fork context has two segments. + * Those are from the current case and the body of the previous case. + */ + const parentForkContext = this.forkContext; + const forkContext = this.pushForkContext(); + + forkContext.add(parentForkContext.makeNext(0, -1)); + + /* + * Save `default` chunk info. + * If the `default` label is not at the last, we must make a path from + * the last `case` to the `default` chunk. + */ + if (isDefault) { + context.defaultSegments = parentForkContext.head; + if (isEmpty) { + context.foundDefault = true; + } else { + context.defaultBodySegments = forkContext.head; + } + } else { + if (!isEmpty && context.foundDefault) { + context.foundDefault = false; + context.defaultBodySegments = forkContext.head; + } + } + + context.lastIsDefault = isDefault; + context.countForks += 1; + } + + //-------------------------------------------------------------------------- + // TryStatement + //-------------------------------------------------------------------------- + + /** + * Creates a context object of TryStatement and stacks it. + * @param {boolean} hasFinalizer `true` if the try statement has a + * `finally` block. + * @returns {void} + */ + pushTryContext(hasFinalizer) { + this.tryContext = { + upper: this.tryContext, + position: 'try', + hasFinalizer, + + returnedForkContext: hasFinalizer + ? ForkContext.newEmpty(this.forkContext) + : null, + + thrownForkContext: ForkContext.newEmpty(this.forkContext), + lastOfTryIsReachable: false, + lastOfCatchIsReachable: false, + }; + } + + /** + * Pops the last context of TryStatement and finalizes it. + * @returns {void} + */ + popTryContext() { + const context = this.tryContext; + + this.tryContext = context.upper; + + if (context.position === 'catch') { + // Merges two paths from the `try` block and `catch` block merely. + this.popForkContext(); + return; + } + + /* + * The following process is executed only when there is the `finally` + * block. + */ + + const returned = context.returnedForkContext; + const thrown = context.thrownForkContext; + + if (returned.empty && thrown.empty) { + return; + } + + // Separate head to normal paths and leaving paths. + const headSegments = this.forkContext.head; + + this.forkContext = this.forkContext.upper; + const normalSegments = headSegments.slice(0, (headSegments.length / 2) | 0); + const leavingSegments = headSegments.slice((headSegments.length / 2) | 0); + + // Forwards the leaving path to upper contexts. + if (!returned.empty) { + getReturnContext(this).returnedForkContext.add(leavingSegments); + } + if (!thrown.empty) { + getThrowContext(this).thrownForkContext.add(leavingSegments); + } + + // Sets the normal path as the next. + this.forkContext.replaceHead(normalSegments); + + /* + * If both paths of the `try` block and the `catch` block are + * unreachable, the next path becomes unreachable as well. + */ + if (!context.lastOfTryIsReachable && !context.lastOfCatchIsReachable) { + this.forkContext.makeUnreachable(); + } + } + + /** + * Makes a code path segment for a `catch` block. + * @returns {void} + */ + makeCatchBlock() { + const context = this.tryContext; + const forkContext = this.forkContext; + const thrown = context.thrownForkContext; + + // Update state. + context.position = 'catch'; + context.thrownForkContext = ForkContext.newEmpty(forkContext); + context.lastOfTryIsReachable = forkContext.reachable; + + // Merge thrown paths. + thrown.add(forkContext.head); + const thrownSegments = thrown.makeNext(0, -1); + + // Fork to a bypass and the merged thrown path. + this.pushForkContext(); + this.forkBypassPath(); + this.forkContext.add(thrownSegments); + } + + /** + * Makes a code path segment for a `finally` block. + * + * In the `finally` block, parallel paths are created. The parallel paths + * are used as leaving-paths. The leaving-paths are paths from `return` + * statements and `throw` statements in a `try` block or a `catch` block. + * @returns {void} + */ + makeFinallyBlock() { + const context = this.tryContext; + let forkContext = this.forkContext; + const returned = context.returnedForkContext; + const thrown = context.thrownForkContext; + const headOfLeavingSegments = forkContext.head; + + // Update state. + if (context.position === 'catch') { + // Merges two paths from the `try` block and `catch` block. + this.popForkContext(); + forkContext = this.forkContext; + + context.lastOfCatchIsReachable = forkContext.reachable; + } else { + context.lastOfTryIsReachable = forkContext.reachable; + } + context.position = 'finally'; + + if (returned.empty && thrown.empty) { + // This path does not leave. + return; + } + + /* + * Create a parallel segment from merging returned and thrown. + * This segment will leave at the end of this finally block. + */ + const segments = forkContext.makeNext(-1, -1); + + for (let i = 0; i < forkContext.count; ++i) { + const prevSegsOfLeavingSegment = [headOfLeavingSegments[i]]; + + for (let j = 0; j < returned.segmentsList.length; ++j) { + prevSegsOfLeavingSegment.push(returned.segmentsList[j][i]); + } + for (let j = 0; j < thrown.segmentsList.length; ++j) { + prevSegsOfLeavingSegment.push(thrown.segmentsList[j][i]); + } + + segments.push( + CodePathSegment.newNext( + this.idGenerator.next(), + prevSegsOfLeavingSegment, + ), + ); + } + + this.pushForkContext(true); + this.forkContext.add(segments); + } + + /** + * Makes a code path segment from the first throwable node to the `catch` + * block or the `finally` block. + * @returns {void} + */ + makeFirstThrowablePathInTryBlock() { + const forkContext = this.forkContext; + + if (!forkContext.reachable) { + return; + } + + const context = getThrowContext(this); + + if ( + context === this || + context.position !== 'try' || + !context.thrownForkContext.empty + ) { + return; + } + + context.thrownForkContext.add(forkContext.head); + forkContext.replaceHead(forkContext.makeNext(-1, -1)); + } + + //-------------------------------------------------------------------------- + // Loop Statements + //-------------------------------------------------------------------------- + + /** + * Creates a context object of a loop statement and stacks it. + * @param {string} type The type of the node which was triggered. One of + * `WhileStatement`, `DoWhileStatement`, `ForStatement`, `ForInStatement`, + * and `ForStatement`. + * @param {string|null} label A label of the node which was triggered. + * @throws {Error} (Unreachable - unknown type.) + * @returns {void} + */ + pushLoopContext(type, label) { + const forkContext = this.forkContext; + const breakContext = this.pushBreakContext(true, label); + + switch (type) { + case 'WhileStatement': + this.pushChoiceContext('loop', false); + this.loopContext = { + upper: this.loopContext, + type, + label, + test: void 0, + continueDestSegments: null, + brokenForkContext: breakContext.brokenForkContext, + }; + break; + + case 'DoWhileStatement': + this.pushChoiceContext('loop', false); + this.loopContext = { + upper: this.loopContext, + type, + label, + test: void 0, + entrySegments: null, + continueForkContext: ForkContext.newEmpty(forkContext), + brokenForkContext: breakContext.brokenForkContext, + }; + break; + + case 'ForStatement': + this.pushChoiceContext('loop', false); + this.loopContext = { + upper: this.loopContext, + type, + label, + test: void 0, + endOfInitSegments: null, + testSegments: null, + endOfTestSegments: null, + updateSegments: null, + endOfUpdateSegments: null, + continueDestSegments: null, + brokenForkContext: breakContext.brokenForkContext, + }; + break; + + case 'ForInStatement': + case 'ForOfStatement': + this.loopContext = { + upper: this.loopContext, + type, + label, + prevSegments: null, + leftSegments: null, + endOfLeftSegments: null, + continueDestSegments: null, + brokenForkContext: breakContext.brokenForkContext, + }; + break; + + /* c8 ignore next */ + default: + throw new Error(`unknown type: "${type}"`); + } + } + + /** + * Pops the last context of a loop statement and finalizes it. + * @throws {Error} (Unreachable - unknown type.) + * @returns {void} + */ + popLoopContext() { + const context = this.loopContext; + + this.loopContext = context.upper; + + const forkContext = this.forkContext; + const brokenForkContext = this.popBreakContext().brokenForkContext; + + // Creates a looped path. + switch (context.type) { + case 'WhileStatement': + case 'ForStatement': + this.popChoiceContext(); + makeLooped(this, forkContext.head, context.continueDestSegments); + break; + + case 'DoWhileStatement': { + const choiceContext = this.popChoiceContext(); + + if (!choiceContext.processed) { + choiceContext.trueForkContext.add(forkContext.head); + choiceContext.falseForkContext.add(forkContext.head); + } + if (context.test !== true) { + brokenForkContext.addAll(choiceContext.falseForkContext); + } + + // `true` paths go to looping. + const segmentsList = choiceContext.trueForkContext.segmentsList; + + for (let i = 0; i < segmentsList.length; ++i) { + makeLooped(this, segmentsList[i], context.entrySegments); + } + break; + } + + case 'ForInStatement': + case 'ForOfStatement': + brokenForkContext.add(forkContext.head); + makeLooped(this, forkContext.head, context.leftSegments); + break; + + /* c8 ignore next */ + default: + throw new Error('unreachable'); + } + + // Go next. + if (brokenForkContext.empty) { + forkContext.replaceHead(forkContext.makeUnreachable(-1, -1)); + } else { + forkContext.replaceHead(brokenForkContext.makeNext(0, -1)); + } + } + + /** + * Makes a code path segment for the test part of a WhileStatement. + * @param {boolean|undefined} test The test value (only when constant). + * @returns {void} + */ + makeWhileTest(test) { + const context = this.loopContext; + const forkContext = this.forkContext; + const testSegments = forkContext.makeNext(0, -1); + + // Update state. + context.test = test; + context.continueDestSegments = testSegments; + forkContext.replaceHead(testSegments); + } + + /** + * Makes a code path segment for the body part of a WhileStatement. + * @returns {void} + */ + makeWhileBody() { + const context = this.loopContext; + const choiceContext = this.choiceContext; + const forkContext = this.forkContext; + + if (!choiceContext.processed) { + choiceContext.trueForkContext.add(forkContext.head); + choiceContext.falseForkContext.add(forkContext.head); + } + + // Update state. + if (context.test !== true) { + context.brokenForkContext.addAll(choiceContext.falseForkContext); + } + forkContext.replaceHead(choiceContext.trueForkContext.makeNext(0, -1)); + } + + /** + * Makes a code path segment for the body part of a DoWhileStatement. + * @returns {void} + */ + makeDoWhileBody() { + const context = this.loopContext; + const forkContext = this.forkContext; + const bodySegments = forkContext.makeNext(-1, -1); + + // Update state. + context.entrySegments = bodySegments; + forkContext.replaceHead(bodySegments); + } + + /** + * Makes a code path segment for the test part of a DoWhileStatement. + * @param {boolean|undefined} test The test value (only when constant). + * @returns {void} + */ + makeDoWhileTest(test) { + const context = this.loopContext; + const forkContext = this.forkContext; + + context.test = test; + + // Creates paths of `continue` statements. + if (!context.continueForkContext.empty) { + context.continueForkContext.add(forkContext.head); + const testSegments = context.continueForkContext.makeNext(0, -1); + + forkContext.replaceHead(testSegments); + } + } + + /** + * Makes a code path segment for the test part of a ForStatement. + * @param {boolean|undefined} test The test value (only when constant). + * @returns {void} + */ + makeForTest(test) { + const context = this.loopContext; + const forkContext = this.forkContext; + const endOfInitSegments = forkContext.head; + const testSegments = forkContext.makeNext(-1, -1); + + // Update state. + context.test = test; + context.endOfInitSegments = endOfInitSegments; + context.continueDestSegments = context.testSegments = testSegments; + forkContext.replaceHead(testSegments); + } + + /** + * Makes a code path segment for the update part of a ForStatement. + * @returns {void} + */ + makeForUpdate() { + const context = this.loopContext; + const choiceContext = this.choiceContext; + const forkContext = this.forkContext; + + // Make the next paths of the test. + if (context.testSegments) { + finalizeTestSegmentsOfFor(context, choiceContext, forkContext.head); + } else { + context.endOfInitSegments = forkContext.head; + } + + // Update state. + const updateSegments = forkContext.makeDisconnected(-1, -1); + + context.continueDestSegments = context.updateSegments = updateSegments; + forkContext.replaceHead(updateSegments); + } + + /** + * Makes a code path segment for the body part of a ForStatement. + * @returns {void} + */ + makeForBody() { + const context = this.loopContext; + const choiceContext = this.choiceContext; + const forkContext = this.forkContext; + + // Update state. + if (context.updateSegments) { + context.endOfUpdateSegments = forkContext.head; + + // `update` -> `test` + if (context.testSegments) { + makeLooped(this, context.endOfUpdateSegments, context.testSegments); + } + } else if (context.testSegments) { + finalizeTestSegmentsOfFor(context, choiceContext, forkContext.head); + } else { + context.endOfInitSegments = forkContext.head; + } + + let bodySegments = context.endOfTestSegments; + + if (!bodySegments) { + /* + * If there is not the `test` part, the `body` path comes from the + * `init` part and the `update` part. + */ + const prevForkContext = ForkContext.newEmpty(forkContext); + + prevForkContext.add(context.endOfInitSegments); + if (context.endOfUpdateSegments) { + prevForkContext.add(context.endOfUpdateSegments); + } + + bodySegments = prevForkContext.makeNext(0, -1); + } + context.continueDestSegments = context.continueDestSegments || bodySegments; + forkContext.replaceHead(bodySegments); + } + + /** + * Makes a code path segment for the left part of a ForInStatement and a + * ForOfStatement. + * @returns {void} + */ + makeForInOfLeft() { + const context = this.loopContext; + const forkContext = this.forkContext; + const leftSegments = forkContext.makeDisconnected(-1, -1); + + // Update state. + context.prevSegments = forkContext.head; + context.leftSegments = context.continueDestSegments = leftSegments; + forkContext.replaceHead(leftSegments); + } + + /** + * Makes a code path segment for the right part of a ForInStatement and a + * ForOfStatement. + * @returns {void} + */ + makeForInOfRight() { + const context = this.loopContext; + const forkContext = this.forkContext; + const temp = ForkContext.newEmpty(forkContext); + + temp.add(context.prevSegments); + const rightSegments = temp.makeNext(-1, -1); + + // Update state. + context.endOfLeftSegments = forkContext.head; + forkContext.replaceHead(rightSegments); + } + + /** + * Makes a code path segment for the body part of a ForInStatement and a + * ForOfStatement. + * @returns {void} + */ + makeForInOfBody() { + const context = this.loopContext; + const forkContext = this.forkContext; + const temp = ForkContext.newEmpty(forkContext); + + temp.add(context.endOfLeftSegments); + const bodySegments = temp.makeNext(-1, -1); + + // Make a path: `right` -> `left`. + makeLooped(this, forkContext.head, context.leftSegments); + + // Update state. + context.brokenForkContext.add(forkContext.head); + forkContext.replaceHead(bodySegments); + } + + //-------------------------------------------------------------------------- + // Control Statements + //-------------------------------------------------------------------------- + + /** + * Creates new context for BreakStatement. + * @param {boolean} breakable The flag to indicate it can break by + * an unlabeled BreakStatement. + * @param {string|null} label The label of this context. + * @returns {Object} The new context. + */ + pushBreakContext(breakable, label) { + this.breakContext = { + upper: this.breakContext, + breakable, + label, + brokenForkContext: ForkContext.newEmpty(this.forkContext), + }; + return this.breakContext; + } + + /** + * Removes the top item of the break context stack. + * @returns {Object} The removed context. + */ + popBreakContext() { + const context = this.breakContext; + const forkContext = this.forkContext; + + this.breakContext = context.upper; + + // Process this context here for other than switches and loops. + if (!context.breakable) { + const brokenForkContext = context.brokenForkContext; + + if (!brokenForkContext.empty) { + brokenForkContext.add(forkContext.head); + forkContext.replaceHead(brokenForkContext.makeNext(0, -1)); + } + } + + return context; + } + + /** + * Makes a path for a `break` statement. + * + * It registers the head segment to a context of `break`. + * It makes new unreachable segment, then it set the head with the segment. + * @param {string} label A label of the break statement. + * @returns {void} + */ + makeBreak(label) { + const forkContext = this.forkContext; + + if (!forkContext.reachable) { + return; + } + + const context = getBreakContext(this, label); + + if (context) { + context.brokenForkContext.add(forkContext.head); + } + + /* c8 ignore next */ + forkContext.replaceHead(forkContext.makeUnreachable(-1, -1)); + } + + /** + * Makes a path for a `continue` statement. + * + * It makes a looping path. + * It makes new unreachable segment, then it set the head with the segment. + * @param {string} label A label of the continue statement. + * @returns {void} + */ + makeContinue(label) { + const forkContext = this.forkContext; + + if (!forkContext.reachable) { + return; + } + + const context = getContinueContext(this, label); + + if (context) { + if (context.continueDestSegments) { + makeLooped(this, forkContext.head, context.continueDestSegments); + + // If the context is a for-in/of loop, this effects a break also. + if ( + context.type === 'ForInStatement' || + context.type === 'ForOfStatement' + ) { + context.brokenForkContext.add(forkContext.head); + } + } else { + context.continueForkContext.add(forkContext.head); + } + } + forkContext.replaceHead(forkContext.makeUnreachable(-1, -1)); + } + + /** + * Makes a path for a `return` statement. + * + * It registers the head segment to a context of `return`. + * It makes new unreachable segment, then it set the head with the segment. + * @returns {void} + */ + makeReturn() { + const forkContext = this.forkContext; + + if (forkContext.reachable) { + getReturnContext(this).returnedForkContext.add(forkContext.head); + forkContext.replaceHead(forkContext.makeUnreachable(-1, -1)); + } + } + + /** + * Makes a path for a `throw` statement. + * + * It registers the head segment to a context of `throw`. + * It makes new unreachable segment, then it set the head with the segment. + * @returns {void} + */ + makeThrow() { + const forkContext = this.forkContext; + + if (forkContext.reachable) { + getThrowContext(this).thrownForkContext.add(forkContext.head); + forkContext.replaceHead(forkContext.makeUnreachable(-1, -1)); + } + } + + /** + * Makes the final path. + * @returns {void} + */ + makeFinal() { + const segments = this.currentSegments; + + if (segments.length > 0 && segments[0].reachable) { + this.returnedForkContext.add(segments); + } + } +} + +module.exports = CodePathState; diff --git a/packages/eslint-plugin-react-hooks/src/code-path-analysis/code-path.js b/packages/eslint-plugin-react-hooks/src/code-path-analysis/code-path.js new file mode 100644 index 0000000000000..167d9be7af80f --- /dev/null +++ b/packages/eslint-plugin-react-hooks/src/code-path-analysis/code-path.js @@ -0,0 +1,239 @@ +'use strict'; + +//------------------------------------------------------------------------------ +// Requirements +//------------------------------------------------------------------------------ + +// eslint-disable-next-line +const CodePathState = require('./code-path-state'); +// eslint-disable-next-line +const IdGenerator = require('./id-generator'); + +//------------------------------------------------------------------------------ +// Public Interface +//------------------------------------------------------------------------------ + +/** + * A code path. + */ +class CodePath { + /** + * Creates a new instance. + * @param {Object} options Options for the function (see below). + * @param {string} options.id An identifier. + * @param {string} options.origin The type of code path origin. + * @param {CodePath|null} options.upper The code path of the upper function scope. + * @param {Function} options.onLooped A callback function to notify looping. + */ + constructor({id, origin, upper, onLooped}) { + /** + * The identifier of this code path. + * Rules use it to store additional information of each rule. + * @type {string} + */ + this.id = id; + + /** + * The reason that this code path was started. May be "program", + * "function", "class-field-initializer", or "class-static-block". + * @type {string} + */ + this.origin = origin; + + /** + * The code path of the upper function scope. + * @type {CodePath|null} + */ + this.upper = upper; + + /** + * The code paths of nested function scopes. + * @type {CodePath[]} + */ + this.childCodePaths = []; + + // Initializes internal state. + Object.defineProperty(this, 'internal', { + value: new CodePathState(new IdGenerator(`${id}_`), onLooped), + }); + + // Adds this into `childCodePaths` of `upper`. + if (upper) { + upper.childCodePaths.push(this); + } + } + + /** + * Gets the state of a given code path. + * @param {CodePath} codePath A code path to get. + * @returns {CodePathState} The state of the code path. + */ + static getState(codePath) { + return codePath.internal; + } + + /** + * The initial code path segment. + * @type {CodePathSegment} + */ + get initialSegment() { + return this.internal.initialSegment; + } + + /** + * Final code path segments. + * This array is a mix of `returnedSegments` and `thrownSegments`. + * @type {CodePathSegment[]} + */ + get finalSegments() { + return this.internal.finalSegments; + } + + /** + * Final code path segments which is with `return` statements. + * This array contains the last path segment if it's reachable. + * Since the reachable last path returns `undefined`. + * @type {CodePathSegment[]} + */ + get returnedSegments() { + return this.internal.returnedForkContext; + } + + /** + * Final code path segments which is with `throw` statements. + * @type {CodePathSegment[]} + */ + get thrownSegments() { + return this.internal.thrownForkContext; + } + + /** + * Current code path segments. + * @type {CodePathSegment[]} + */ + get currentSegments() { + return this.internal.currentSegments; + } + + /** + * Traverses all segments in this code path. + * + * codePath.traverseSegments(function(segment, controller) { + * // do something. + * }); + * + * This method enumerates segments in order from the head. + * + * The `controller` object has two methods. + * + * - `controller.skip()` - Skip the following segments in this branch. + * - `controller.break()` - Skip all following segments. + * @param {Object} [options] Omittable. + * @param {CodePathSegment} [options.first] The first segment to traverse. + * @param {CodePathSegment} [options.last] The last segment to traverse. + * @param {Function} callback A callback function. + * @returns {void} + */ + traverseSegments(options, callback) { + let resolvedOptions; + let resolvedCallback; + + if (typeof options === 'function') { + resolvedCallback = options; + resolvedOptions = {}; + } else { + resolvedOptions = options || {}; + resolvedCallback = callback; + } + + const startSegment = resolvedOptions.first || this.internal.initialSegment; + const lastSegment = resolvedOptions.last; + + let item = null; + let index = 0; + let end = 0; + let segment = null; + const visited = Object.create(null); + const stack = [[startSegment, 0]]; + let skippedSegment = null; + let broken = false; + const controller = { + skip() { + if (stack.length <= 1) { + broken = true; + } else { + skippedSegment = stack[stack.length - 2][0]; + } + }, + break() { + broken = true; + }, + }; + + /** + * Checks a given previous segment has been visited. + * @param {CodePathSegment} prevSegment A previous segment to check. + * @returns {boolean} `true` if the segment has been visited. + */ + function isVisited(prevSegment) { + return ( + visited[prevSegment.id] || segment.isLoopedPrevSegment(prevSegment) + ); + } + + while (stack.length > 0) { + item = stack[stack.length - 1]; + segment = item[0]; + index = item[1]; + + if (index === 0) { + // Skip if this segment has been visited already. + if (visited[segment.id]) { + stack.pop(); + continue; + } + + // Skip if all previous segments have not been visited. + if ( + segment !== startSegment && + segment.prevSegments.length > 0 && + !segment.prevSegments.every(isVisited) + ) { + stack.pop(); + continue; + } + + // Reset the flag of skipping if all branches have been skipped. + if (skippedSegment && segment.prevSegments.includes(skippedSegment)) { + skippedSegment = null; + } + visited[segment.id] = true; + + // Call the callback when the first time. + if (!skippedSegment) { + resolvedCallback.call(this, segment, controller); + if (segment === lastSegment) { + controller.skip(); + } + if (broken) { + break; + } + } + } + + // Update the stack. + end = segment.nextSegments.length - 1; + if (index < end) { + item[1] += 1; + stack.push([segment.nextSegments[index], 0]); + } else if (index === end) { + item[0] = segment.nextSegments[index]; + item[1] = 0; + } else { + stack.pop(); + } + } + } +} + +module.exports = CodePath; diff --git a/packages/eslint-plugin-react-hooks/src/code-path-analysis/fork-context.js b/packages/eslint-plugin-react-hooks/src/code-path-analysis/fork-context.js new file mode 100644 index 0000000000000..528aaa41e15fb --- /dev/null +++ b/packages/eslint-plugin-react-hooks/src/code-path-analysis/fork-context.js @@ -0,0 +1,252 @@ +'use strict'; + +//------------------------------------------------------------------------------ +// Requirements +//------------------------------------------------------------------------------ + +// eslint-disable-next-line +const assert = require('./assert'); +// eslint-disable-next-line +const CodePathSegment = require('./code-path-segment'); + +//------------------------------------------------------------------------------ +// Helpers +//------------------------------------------------------------------------------ + +/** + * Gets whether or not a given segment is reachable. + * @param {CodePathSegment} segment A segment to get. + * @returns {boolean} `true` if the segment is reachable. + */ +function isReachable(segment) { + return segment.reachable; +} + +/** + * Creates new segments from the specific range of `context.segmentsList`. + * + * When `context.segmentsList` is `[[a, b], [c, d], [e, f]]`, `begin` is `0`, and + * `end` is `-1`, this creates `[g, h]`. This `g` is from `a`, `c`, and `e`. + * This `h` is from `b`, `d`, and `f`. + * @param {ForkContext} context An instance. + * @param {number} begin The first index of the previous segments. + * @param {number} end The last index of the previous segments. + * @param {Function} create A factory function of new segments. + * @returns {CodePathSegment[]} New segments. + */ +function makeSegments(context, begin, end, create) { + const list = context.segmentsList; + + const normalizedBegin = begin >= 0 ? begin : list.length + begin; + const normalizedEnd = end >= 0 ? end : list.length + end; + + const segments = []; + + for (let i = 0; i < context.count; ++i) { + const allPrevSegments = []; + + for (let j = normalizedBegin; j <= normalizedEnd; ++j) { + allPrevSegments.push(list[j][i]); + } + + segments.push(create(context.idGenerator.next(), allPrevSegments)); + } + + return segments; +} + +/** + * `segments` becomes doubly in a `finally` block. Then if a code path exits by a + * control statement (such as `break`, `continue`) from the `finally` block, the + * destination's segments may be half of the source segments. In that case, this + * merges segments. + * @param {ForkContext} context An instance. + * @param {CodePathSegment[]} segments Segments to merge. + * @returns {CodePathSegment[]} The merged segments. + */ +function mergeExtraSegments(context, segments) { + let currentSegments = segments; + + while (currentSegments.length > context.count) { + const merged = []; + + for ( + let i = 0, length = (currentSegments.length / 2) | 0; + i < length; + ++i + ) { + merged.push( + CodePathSegment.newNext(context.idGenerator.next(), [ + currentSegments[i], + currentSegments[i + length], + ]), + ); + } + currentSegments = merged; + } + return currentSegments; +} + +//------------------------------------------------------------------------------ +// Public Interface +//------------------------------------------------------------------------------ + +/** + * A class to manage forking. + */ +class ForkContext { + /** + * @param {IdGenerator} idGenerator An identifier generator for segments. + * @param {ForkContext|null} upper An upper fork context. + * @param {number} count A number of parallel segments. + */ + constructor(idGenerator, upper, count) { + this.idGenerator = idGenerator; + this.upper = upper; + this.count = count; + this.segmentsList = []; + } + + /** + * The head segments. + * @type {CodePathSegment[]} + */ + get head() { + const list = this.segmentsList; + + return list.length === 0 ? [] : list[list.length - 1]; + } + + /** + * A flag which shows empty. + * @type {boolean} + */ + get empty() { + return this.segmentsList.length === 0; + } + + /** + * A flag which shows reachable. + * @type {boolean} + */ + get reachable() { + const segments = this.head; + + return segments.length > 0 && segments.some(isReachable); + } + + /** + * Creates new segments from this context. + * @param {number} begin The first index of previous segments. + * @param {number} end The last index of previous segments. + * @returns {CodePathSegment[]} New segments. + */ + makeNext(begin, end) { + return makeSegments(this, begin, end, CodePathSegment.newNext); + } + + /** + * Creates new segments from this context. + * The new segments is always unreachable. + * @param {number} begin The first index of previous segments. + * @param {number} end The last index of previous segments. + * @returns {CodePathSegment[]} New segments. + */ + makeUnreachable(begin, end) { + return makeSegments(this, begin, end, CodePathSegment.newUnreachable); + } + + /** + * Creates new segments from this context. + * The new segments don't have connections for previous segments. + * But these inherit the reachable flag from this context. + * @param {number} begin The first index of previous segments. + * @param {number} end The last index of previous segments. + * @returns {CodePathSegment[]} New segments. + */ + makeDisconnected(begin, end) { + return makeSegments(this, begin, end, CodePathSegment.newDisconnected); + } + + /** + * Adds segments into this context. + * The added segments become the head. + * @param {CodePathSegment[]} segments Segments to add. + * @returns {void} + */ + add(segments) { + assert( + segments.length >= this.count, + `${segments.length} >= ${this.count}`, + ); + + this.segmentsList.push(mergeExtraSegments(this, segments)); + } + + /** + * Replaces the head segments with given segments. + * The current head segments are removed. + * @param {CodePathSegment[]} segments Segments to add. + * @returns {void} + */ + replaceHead(segments) { + assert( + segments.length >= this.count, + `${segments.length} >= ${this.count}`, + ); + + this.segmentsList.splice(-1, 1, mergeExtraSegments(this, segments)); + } + + /** + * Adds all segments of a given fork context into this context. + * @param {ForkContext} context A fork context to add. + * @returns {void} + */ + addAll(context) { + assert(context.count === this.count); + + const source = context.segmentsList; + + for (let i = 0; i < source.length; ++i) { + this.segmentsList.push(source[i]); + } + } + + /** + * Clears all segments in this context. + * @returns {void} + */ + clear() { + this.segmentsList = []; + } + + /** + * Creates the root fork context. + * @param {IdGenerator} idGenerator An identifier generator for segments. + * @returns {ForkContext} New fork context. + */ + static newRoot(idGenerator) { + const context = new ForkContext(idGenerator, null, 1); + + context.add([CodePathSegment.newRoot(idGenerator.next())]); + + return context; + } + + /** + * Creates an empty fork context preceded by a given context. + * @param {ForkContext} parentContext The parent fork context. + * @param {boolean} forkLeavingPath A flag which shows inside of `finally` block. + * @returns {ForkContext} New fork context. + */ + static newEmpty(parentContext, forkLeavingPath) { + return new ForkContext( + parentContext.idGenerator, + parentContext, + (forkLeavingPath ? 2 : 1) * parentContext.count, + ); + } +} + +module.exports = ForkContext; diff --git a/packages/eslint-plugin-react-hooks/src/code-path-analysis/id-generator.js b/packages/eslint-plugin-react-hooks/src/code-path-analysis/id-generator.js new file mode 100644 index 0000000000000..ed0f47d83464a --- /dev/null +++ b/packages/eslint-plugin-react-hooks/src/code-path-analysis/id-generator.js @@ -0,0 +1,37 @@ +'use strict'; + +/* eslint-disable react-internal/safe-string-coercion */ + +//------------------------------------------------------------------------------ +// Public Interface +//------------------------------------------------------------------------------ + +/** + * A generator for unique ids. + */ +class IdGenerator { + /** + * @param {string} prefix Optional. A prefix of generated ids. + */ + constructor(prefix) { + this.prefix = String(prefix); + this.n = 0; + } + + /** + * Generates id. + * @returns {string} A generated id. + */ + next() { + this.n = (1 + this.n) | 0; + + /* c8 ignore start */ + if (this.n < 0) { + this.n = 1; + } /* c8 ignore stop */ + + return this.prefix + this.n; + } +} + +module.exports = IdGenerator; diff --git a/packages/eslint-plugin-react-hooks/src/rules/RulesOfHooks.ts b/packages/eslint-plugin-react-hooks/src/rules/RulesOfHooks.ts index 0ab0c5ff21e4b..6be40df53226a 100644 --- a/packages/eslint-plugin-react-hooks/src/rules/RulesOfHooks.ts +++ b/packages/eslint-plugin-react-hooks/src/rules/RulesOfHooks.ts @@ -9,6 +9,9 @@ import type {Rule, Scope} from 'eslint'; import type {CallExpression, DoWhileStatement, Node} from 'estree'; +// @ts-expect-error untyped module +import CodePathAnalyzer from '../code-path-analysis/code-path-analyzer'; + /** * Catch all identifiers that begin with "use" followed by an uppercase Latin * character to exclude identifiers like "user". @@ -184,9 +187,25 @@ const rule = { return getSourceCode().getScope(node); }; - return { + function hasFlowSuppression(node: Node, suppression: string) { + const sourceCode = getSourceCode(); + const comments = sourceCode.getAllComments(); + const flowSuppressionRegex = new RegExp( + '\\$FlowFixMe\\[' + suppression + '\\]', + ); + return comments.some( + commentNode => + flowSuppressionRegex.test(commentNode.value) && + commentNode.loc != null && + node.loc != null && + commentNode.loc.end.line === node.loc.start.line - 1, + ); + } + + const analyzer = new CodePathAnalyzer({ // Maintain code segment path stack as we traverse. - onCodePathSegmentStart: segment => codePathSegmentStack.push(segment), + onCodePathSegmentStart: (segment: Rule.CodePathSegment) => + codePathSegmentStack.push(segment), onCodePathSegmentEnd: () => codePathSegmentStack.pop(), // Maintain code path stack as we traverse. @@ -199,7 +218,7 @@ const rule = { // // Everything is ok if all React Hooks are both reachable from the initial // segment and reachable from every final segment. - onCodePathEnd(codePath, codePathNode) { + onCodePathEnd(codePath: any, codePathNode: Node) { const reactHooksMap = codePathReactHooksMapStack.pop(); if (reactHooksMap?.size === 0) { return; @@ -508,6 +527,11 @@ const rule = { const cycled = cyclic.has(segment.id); for (const hook of reactHooks) { + // Skip reporting if this hook already has a relevant flow suppression. + if (hasFlowSuppression(hook, 'react-rule-hook')) { + continue; + } + // Report an error if a hook may be called more then once. // `use(...)` can be called in loops. if ( @@ -611,6 +635,16 @@ const rule = { } } }, + }); + + return { + '*'(node: any) { + analyzer.enterNode(node); + }, + + '*:exit'(node: any) { + analyzer.leaveNode(node); + }, // Missed opportunity...We could visit all `Identifier`s instead of all // `CallExpression`s and check that _every use_ of a hook name is valid. @@ -696,6 +730,10 @@ const rule = { function getFunctionName(node: Node) { if ( + // @ts-expect-error parser-hermes produces these node types + node.type === 'ComponentDeclaration' || + // @ts-expect-error parser-hermes produces these node types + node.type === 'HookDeclaration' || node.type === 'FunctionDeclaration' || (node.type === 'FunctionExpression' && node.id) ) {