Revert "[DO NOT MERGE UNTIL 5.6] Fix re-exported defaults in ExportInfoMap (microsoft#58837)"

This reverts commit 1948e92.

Author: andrewbranch

src/services/codefixes/importFixes.ts

@@ -1187,7 +1187,7 @@ function getNewImportFixes(
                 const exportEquals = checker.resolveExternalModuleSymbol(exportInfo.moduleSymbol);
                 let namespacePrefix;
                 if (exportEquals !== exportInfo.moduleSymbol) {
-                    namespacePrefix = forEachNameOfDefaultExport(exportEquals, checker, getEmitScriptTarget(compilerOptions), identity)!;
+                    namespacePrefix = forEachNameOfDefaultExport(exportEquals, checker, compilerOptions, /*preferCapitalizedNames*/ false, identity)!;
                 }
                 namespacePrefix ||= moduleSymbolToValidIdentifier(
                     exportInfo.moduleSymbol,
@@ -1544,7 +1544,7 @@ function getExportInfos(
         if (
             defaultInfo
             && symbolFlagsHaveMeaning(checker.getSymbolFlags(defaultInfo.symbol), currentTokenMeaning)
-            && forEachNameOfDefaultExport(defaultInfo.symbol, checker, getEmitScriptTarget(compilerOptions), (name, capitalizedName) => (isJsxTagName ? capitalizedName ?? name : name) === symbolName)
+            && forEachNameOfDefaultExport(defaultInfo.symbol, checker, compilerOptions, isJsxTagName, name => name === symbolName)
         ) {
             addSymbol(moduleSymbol, sourceFile, defaultInfo.symbol, defaultInfo.exportKind, program, isFromPackageJson);
         }

src/services/exportInfoMap.ts

@@ -4,6 +4,7 @@ import {
     append,
     arrayIsEqualTo,
     CancellationToken,
+    CompilerOptions,
     consumesNodeCoreModules,
     createMultiMap,
     Debug,
@@ -17,7 +18,9 @@ import {
     GetCanonicalFileName,
     getDefaultLikeExportNameFromDeclaration,
     getDirectoryPath,
+    getEmitScriptTarget,
     getLocalSymbolForExportDefault,
+    getNamesForExportedSymbol,
     getNodeModulePathParts,
     getPackageNameFromTypesPackageName,
     getRegexFromPattern,
@@ -43,7 +46,6 @@ import {
     Path,
     pathContainsNodeModules,
     Program,
-    ScriptTarget,
     skipAlias,
     SourceFile,
     startsWith,
@@ -196,7 +198,7 @@ export function createCacheableExportInfoMap(host: CacheableExportInfoMapHost):
             //    get a better name.
             const names = exportKind === ExportKind.Named || isExternalModuleSymbol(namedSymbol)
                 ? unescapeLeadingUnderscores(symbolTableKey)
-                : getNamesForExportedSymbol(namedSymbol, checker, /*scriptTarget*/ undefined);
+                : getNamesForExportedSymbol(namedSymbol, /*scriptTarget*/ undefined);
 
             const symbolName = typeof names === "string" ? names : names[0];
             const capitalizedSymbolName = typeof names === "string" ? undefined : names[1];
@@ -556,21 +558,12 @@ function isImportableSymbol(symbol: Symbol, checker: TypeChecker) {
     return !checker.isUndefinedSymbol(symbol) && !checker.isUnknownSymbol(symbol) && !isKnownSymbol(symbol) && !isPrivateIdentifierSymbol(symbol);
 }
 
-function getNamesForExportedSymbol(defaultExport: Symbol, checker: TypeChecker, scriptTarget: ScriptTarget | undefined) {
-    let names: string | string[] | undefined;
-    forEachNameOfDefaultExport(defaultExport, checker, scriptTarget, (name, capitalizedName) => {
-        names = capitalizedName ? [name, capitalizedName] : name;
-        return true;
-    });
-    return Debug.checkDefined(names);
-}
-
 /**
  * @internal
  * May call `cb` multiple times with the same name.
  * Terminates when `cb` returns a truthy value.
  */
-export function forEachNameOfDefaultExport<T>(defaultExport: Symbol, checker: TypeChecker, scriptTarget: ScriptTarget | undefined, cb: (name: string, capitalizedName?: string) => T | undefined): T | undefined {
+export function forEachNameOfDefaultExport<T>(defaultExport: Symbol, checker: TypeChecker, compilerOptions: CompilerOptions, preferCapitalizedNames: boolean, cb: (name: string) => T | undefined): T | undefined {
     let chain: Symbol[] | undefined;
     let current: Symbol | undefined = defaultExport;
 
@@ -595,10 +588,7 @@ export function forEachNameOfDefaultExport<T>(defaultExport: Symbol, checker: Ty
 
     for (const symbol of chain ?? emptyArray) {
         if (symbol.parent && isExternalModuleSymbol(symbol.parent)) {
-            const final = cb(
-                moduleSymbolToValidIdentifier(symbol.parent, scriptTarget, /*forceCapitalize*/ false),
-                moduleSymbolToValidIdentifier(symbol.parent, scriptTarget, /*forceCapitalize*/ true),
-            );
+            const final = cb(moduleSymbolToValidIdentifier(symbol.parent, getEmitScriptTarget(compilerOptions), preferCapitalizedNames));
             if (final) return final;
         }
     }

src/services/utilities.ts

@@ -4024,13 +4024,22 @@ export function firstOrOnly<T>(valueOrArray: T | readonly T[]): T {
     return isArray(valueOrArray) ? first(valueOrArray) : valueOrArray;
 }
 
-/**
- * If a type checker and multiple files are available, consider using `forEachNameOfDefaultExport`
- * instead, which searches for names of re-exported defaults/namespaces in target files.
- * @internal
- */
+/** @internal */
+export function getNamesForExportedSymbol(symbol: Symbol, scriptTarget: ScriptTarget | undefined): string | [lowercase: string, capitalized: string] {
+    if (needsNameFromDeclaration(symbol)) {
+        const fromDeclaration = getDefaultLikeExportNameFromDeclaration(symbol);
+        if (fromDeclaration) return fromDeclaration;
+        const fileNameCase = moduleSymbolToValidIdentifier(getSymbolParentOrFail(symbol), scriptTarget, /*forceCapitalize*/ false);
+        const capitalized = moduleSymbolToValidIdentifier(getSymbolParentOrFail(symbol), scriptTarget, /*forceCapitalize*/ true);
+        if (fileNameCase === capitalized) return fileNameCase;
+        return [fileNameCase, capitalized];
+    }
+    return symbol.name;
+}
+
+/** @internal */
 export function getNameForExportedSymbol(symbol: Symbol, scriptTarget: ScriptTarget | undefined, preferCapitalized?: boolean) {
-    if (symbol.escapedName === InternalSymbolName.ExportEquals || symbol.escapedName === InternalSymbolName.Default) {
+    if (needsNameFromDeclaration(symbol)) {
         // Names for default exports:
         // - export default foo => foo
         // - export { foo as default } => foo
@@ -4041,11 +4050,11 @@ export function getNameForExportedSymbol(symbol: Symbol, scriptTarget: ScriptTar
     return symbol.name;
 }
 
-/**
- * If a type checker and multiple files are available, consider using `forEachNameOfDefaultExport`
- * instead, which searches for names of re-exported defaults/namespaces in target files.
- * @internal
- */
+function needsNameFromDeclaration(symbol: Symbol) {
+    return !(symbol.flags & SymbolFlags.Transient) && (symbol.escapedName === InternalSymbolName.ExportEquals || symbol.escapedName === InternalSymbolName.Default);
+}
+
+/** @internal */
 export function getDefaultLikeExportNameFromDeclaration(symbol: Symbol): string | undefined {
     return firstDefined(symbol.declarations, d => {
         // "export default" in this case. See `ExportAssignment`for more details.

tests/baselines/reference/tsserver/fourslashServer/completionsImport_jsModuleExportsAssignment.js

@@ -375,7 +375,7 @@ Info seq  [hh:mm:ss:mss] getCompletionData: Is inside comment: *
 Info seq  [hh:mm:ss:mss] getCompletionData: Get previous token: *
 Info seq  [hh:mm:ss:mss] getExportInfoMap: cache miss or empty; calculating new results
 Info seq  [hh:mm:ss:mss] getExportInfoMap: done in * ms
-Info seq  [hh:mm:ss:mss] collectAutoImports: resolved 0 module specifiers, plus 0 ambient and 4 from cache
+Info seq  [hh:mm:ss:mss] collectAutoImports: resolved 0 module specifiers, plus 0 ambient and 3 from cache
 Info seq  [hh:mm:ss:mss] collectAutoImports: response is incomplete
 Info seq  [hh:mm:ss:mss] collectAutoImports: *
 Info seq  [hh:mm:ss:mss] getCompletionData: Semantic work: *
@@ -1048,19 +1048,6 @@ Info seq  [hh:mm:ss:mss] response:
               "fileName": "/third_party/marked/src/defaults.js"
             }
           },
-          {
-            "name": "defaults",
-            "kind": "property",
-            "kindModifiers": "",
-            "sortText": "16",
-            "hasAction": true,
-            "source": "/third_party/marked/src/defaults",
-            "data": {
-              "exportName": "export=",
-              "exportMapKey": "8 * defaults ",
-              "fileName": "/third_party/marked/src/defaults.js"
-            }
-          },
           {
             "name": "defaults",
             "kind": "alias",
@@ -1265,7 +1252,7 @@ Info seq  [hh:mm:ss:mss] getCompletionData: Get current token: *
 Info seq  [hh:mm:ss:mss] getCompletionData: Is inside comment: *
 Info seq  [hh:mm:ss:mss] getCompletionData: Get previous token: *
 Info seq  [hh:mm:ss:mss] getExportInfoMap: cache hit
-Info seq  [hh:mm:ss:mss] collectAutoImports: resolved 0 module specifiers, plus 0 ambient and 4 from cache
+Info seq  [hh:mm:ss:mss] collectAutoImports: resolved 0 module specifiers, plus 0 ambient and 3 from cache
 Info seq  [hh:mm:ss:mss] collectAutoImports: response is incomplete
 Info seq  [hh:mm:ss:mss] collectAutoImports: *
 Info seq  [hh:mm:ss:mss] getCompletionData: Semantic work: *
@@ -1951,19 +1938,6 @@ Info seq  [hh:mm:ss:mss] response:
               "fileName": "/third_party/marked/src/defaults.js"
             }
           },
-          {
-            "name": "defaults",
-            "kind": "property",
-            "kindModifiers": "",
-            "sortText": "16",
-            "hasAction": true,
-            "source": "/third_party/marked/src/defaults",
-            "data": {
-              "exportName": "export=",
-              "exportMapKey": "8 * defaults ",
-              "fileName": "/third_party/marked/src/defaults.js"
-            }
-          },
           {
             "name": "defaults",
             "kind": "alias",