Move string ref coercion to JSX runtime (#28473)

Based on:

- #28464

---

This moves the entire string ref implementation out Fiber and into the
JSX runtime. The string is converted to a callback ref during element
creation. This is a subtle change in behavior, because it will have
already been converted to a callback ref if you access element.prop.ref
or element.ref. But this is only for Meta, because string refs are
disabled entirely in open source. And if it leads to an issue in
practice, the solution is to switch to a different ref type, which Meta
is going to do regardless.

DiffTrain build for commit e3ebcd5.

Author: acdlite

compiled-rn/facebook-fbsource/xplat/js/RKJSModules/vendor/react-test-renderer/cjs/ReactTestRenderer-dev.js

@@ -7,7 +7,7 @@
  * @noflow
  * @nolint
  * @preventMunge
- * @generated SignedSource<<3151ca79177b1e7b421f14db372bfd97>>
+ * @generated SignedSource<<98fc293dc2ddd5bd7ffa9ec7eb7ac707>>
  */
 
 "use strict";
@@ -5656,81 +5656,6 @@ if (__DEV__) {
       };
     }
 
-    /*
-     * The `'' + value` pattern (used in perf-sensitive code) throws for Symbol
-     * and Temporal.* types. See https://github.com/facebook/react/pull/22064.
-     *
-     * The functions in this module will throw an easier-to-understand,
-     * easier-to-debug exception with a clear errors message message explaining the
-     * problem. (Instead of a confusing exception thrown inside the implementation
-     * of the `value` object).
-     */
-    // $FlowFixMe[incompatible-return] only called in DEV, so void return is not possible.
-    function typeName(value) {
-      {
-        // toStringTag is needed for namespaced types like Temporal.Instant
-        var hasToStringTag = typeof Symbol === "function" && Symbol.toStringTag;
-        var type =
-          (hasToStringTag && value[Symbol.toStringTag]) ||
-          value.constructor.name ||
-          "Object"; // $FlowFixMe[incompatible-return]
-
-        return type;
-      }
-    } // $FlowFixMe[incompatible-return] only called in DEV, so void return is not possible.
-
-    function willCoercionThrow(value) {
-      {
-        try {
-          testStringCoercion(value);
-          return false;
-        } catch (e) {
-          return true;
-        }
-      }
-    }
-
-    function testStringCoercion(value) {
-      // If you ended up here by following an exception call stack, here's what's
-      // happened: you supplied an object or symbol value to React (as a prop, key,
-      // DOM attribute, CSS property, string ref, etc.) and when React tried to
-      // coerce it to a string using `'' + value`, an exception was thrown.
-      //
-      // The most common types that will cause this exception are `Symbol` instances
-      // and Temporal objects like `Temporal.Instant`. But any object that has a
-      // `valueOf` or `[Symbol.toPrimitive]` method that throws will also cause this
-      // exception. (Library authors do this to prevent users from using built-in
-      // numeric operators like `+` or comparison operators like `>=` because custom
-      // methods are needed to perform accurate arithmetic or comparison.)
-      //
-      // To fix the problem, coerce this object or symbol value to a string before
-      // passing it to React. The most reliable way is usually `String(value)`.
-      //
-      // To find which value is throwing, check the browser or debugger console.
-      // Before this exception was thrown, there should be `console.error` output
-      // that shows the type (Symbol, Temporal.PlainDate, etc.) that caused the
-      // problem and how that type was used: key, atrribute, input value prop, etc.
-      // In most cases, this console output also shows the component and its
-      // ancestor components where the exception happened.
-      //
-      // eslint-disable-next-line react-internal/safe-string-coercion
-      return "" + value;
-    }
-    function checkPropStringCoercion(value, propName) {
-      {
-        if (willCoercionThrow(value)) {
-          error(
-            "The provided `%s` prop is an unsupported type %s." +
-              " This value must be coerced to a string before using it here.",
-            propName,
-            typeName(value)
-          );
-
-          return testStringCoercion(value); // throw (to help callers find troubleshooting comments)
-        }
-      }
-    }
-
     var ReactCurrentActQueue$3 = ReactSharedInternals.ReactCurrentActQueue;
 
     function getThenablesFromState(state) {
@@ -6010,7 +5935,6 @@ if (__DEV__) {
 
     var didWarnAboutMaps;
     var didWarnAboutGenerators;
-    var didWarnAboutStringRefs;
     var ownerHasKeyUseWarning;
     var ownerHasFunctionTypeWarning;
     var ownerHasSymbolTypeWarning;
@@ -6020,7 +5944,6 @@ if (__DEV__) {
     {
       didWarnAboutMaps = false;
       didWarnAboutGenerators = false;
-      didWarnAboutStringRefs = {};
       /**
        * Warn if there's no key explicitly set on dynamic arrays of children or
        * object keys are not valid. This allows us to keep track of children between
@@ -6065,10 +5988,6 @@ if (__DEV__) {
       };
     }
 
-    function isReactClass(type) {
-      return type.prototype && type.prototype.isReactComponent;
-    }
-
     function unwrapThenable(thenable) {
       var index = thenableIndexCounter$1;
       thenableIndexCounter$1 += 1;
@@ -6080,128 +5999,16 @@ if (__DEV__) {
       return trackUsedThenable(thenableState$1, thenable, index);
     }
 
-    function convertStringRefToCallbackRef(
-      returnFiber,
-      current,
-      element,
-      mixedRef
-    ) {
-      {
-        checkPropStringCoercion(mixedRef, "ref");
-      }
-
-      var stringRef = "" + mixedRef;
-      var owner = element._owner;
-
-      if (!owner) {
-        throw new Error(
-          "Element ref was specified as a string (" +
-            stringRef +
-            ") but no owner was set. This could happen for one of" +
-            " the following reasons:\n" +
-            "1. You may be adding a ref to a function component\n" +
-            "2. You may be adding a ref to a component that was not created inside a component's render method\n" +
-            "3. You have multiple copies of React loaded\n" +
-            "See https://react.dev/link/refs-must-have-owner for more information."
-        );
-      }
-
-      if (owner.tag !== ClassComponent) {
-        throw new Error(
-          "Function components cannot have string refs. " +
-            "We recommend using useRef() instead. " +
-            "Learn more about using refs safely here: " +
-            "https://react.dev/link/strict-mode-string-ref"
-        );
-      }
-
-      {
-        if (
-          // Will already warn with "Function components cannot be given refs"
-          !(typeof element.type === "function" && !isReactClass(element.type))
-        ) {
-          var componentName =
-            getComponentNameFromFiber(returnFiber) || "Component";
-
-          if (!didWarnAboutStringRefs[componentName]) {
-            error(
-              'Component "%s" contains the string ref "%s". Support for string refs ' +
-                "will be removed in a future major release. We recommend using " +
-                "useRef() or createRef() instead. " +
-                "Learn more about using refs safely here: " +
-                "https://react.dev/link/strict-mode-string-ref",
-              componentName,
-              stringRef
-            );
-
-            didWarnAboutStringRefs[componentName] = true;
-          }
-        }
-      }
-
-      var inst = owner.stateNode;
-
-      if (!inst) {
-        throw new Error(
-          "Missing owner for string ref " +
-            stringRef +
-            ". This error is likely caused by a " +
-            "bug in React. Please file an issue."
-        );
-      } // Check if previous string ref matches new string ref
-
-      if (
-        current !== null &&
-        current.ref !== null &&
-        typeof current.ref === "function" &&
-        current.ref._stringRef === stringRef
-      ) {
-        // Reuse the existing string ref
-        var currentRef = current.ref;
-        return currentRef;
-      } // Create a new string ref
-
-      var ref = function (value) {
-        var refs = inst.refs;
-
-        if (value === null) {
-          delete refs[stringRef];
-        } else {
-          refs[stringRef] = value;
-        }
-      };
-
-      ref._stringRef = stringRef;
-      return ref;
-    }
-
     function coerceRef(returnFiber, current, workInProgress, element) {
-      var mixedRef;
+      var ref;
 
       {
         // Old behavior.
-        mixedRef = element.ref;
-      }
-
-      var coercedRef;
-
-      if (
-        typeof mixedRef === "string" ||
-        typeof mixedRef === "number" ||
-        typeof mixedRef === "boolean"
-      ) {
-        coercedRef = convertStringRefToCallbackRef(
-          returnFiber,
-          current,
-          element,
-          mixedRef
-        );
-      } else {
-        coercedRef = mixedRef;
+        ref = element.ref;
       } // TODO: If enableRefAsProp is on, we shouldn't use the `ref` field. We
       // should always read the ref from the prop.
 
-      workInProgress.ref = coercedRef;
+      workInProgress.ref = ref;
     }
 
     function throwOnInvalidObjectType(returnFiber, newChild) {
@@ -26823,7 +26630,82 @@ if (__DEV__) {
       return root;
     }
 
-    var ReactVersion = "19.0.0-canary-29bd6113";
+    var ReactVersion = "19.0.0-canary-fbd6543d";
+
+    /*
+     * The `'' + value` pattern (used in perf-sensitive code) throws for Symbol
+     * and Temporal.* types. See https://github.com/facebook/react/pull/22064.
+     *
+     * The functions in this module will throw an easier-to-understand,
+     * easier-to-debug exception with a clear errors message message explaining the
+     * problem. (Instead of a confusing exception thrown inside the implementation
+     * of the `value` object).
+     */
+    // $FlowFixMe[incompatible-return] only called in DEV, so void return is not possible.
+    function typeName(value) {
+      {
+        // toStringTag is needed for namespaced types like Temporal.Instant
+        var hasToStringTag = typeof Symbol === "function" && Symbol.toStringTag;
+        var type =
+          (hasToStringTag && value[Symbol.toStringTag]) ||
+          value.constructor.name ||
+          "Object"; // $FlowFixMe[incompatible-return]
+
+        return type;
+      }
+    } // $FlowFixMe[incompatible-return] only called in DEV, so void return is not possible.
+
+    function willCoercionThrow(value) {
+      {
+        try {
+          testStringCoercion(value);
+          return false;
+        } catch (e) {
+          return true;
+        }
+      }
+    }
+
+    function testStringCoercion(value) {
+      // If you ended up here by following an exception call stack, here's what's
+      // happened: you supplied an object or symbol value to React (as a prop, key,
+      // DOM attribute, CSS property, string ref, etc.) and when React tried to
+      // coerce it to a string using `'' + value`, an exception was thrown.
+      //
+      // The most common types that will cause this exception are `Symbol` instances
+      // and Temporal objects like `Temporal.Instant`. But any object that has a
+      // `valueOf` or `[Symbol.toPrimitive]` method that throws will also cause this
+      // exception. (Library authors do this to prevent users from using built-in
+      // numeric operators like `+` or comparison operators like `>=` because custom
+      // methods are needed to perform accurate arithmetic or comparison.)
+      //
+      // To fix the problem, coerce this object or symbol value to a string before
+      // passing it to React. The most reliable way is usually `String(value)`.
+      //
+      // To find which value is throwing, check the browser or debugger console.
+      // Before this exception was thrown, there should be `console.error` output
+      // that shows the type (Symbol, Temporal.PlainDate, etc.) that caused the
+      // problem and how that type was used: key, atrribute, input value prop, etc.
+      // In most cases, this console output also shows the component and its
+      // ancestor components where the exception happened.
+      //
+      // eslint-disable-next-line react-internal/safe-string-coercion
+      return "" + value;
+    }
+    function checkPropStringCoercion(value, propName) {
+      {
+        if (willCoercionThrow(value)) {
+          error(
+            "The provided `%s` prop is an unsupported type %s." +
+              " This value must be coerced to a string before using it here.",
+            propName,
+            typeName(value)
+          );
+
+          return testStringCoercion(value); // throw (to help callers find troubleshooting comments)
+        }
+      }
+    }
 
     // Might add PROFILE later.