Update on "[compiler] rfc: Include location information in identifiers and reactive scopes for debugging"

Summary: Using the change detection code to debug codebases that violate the rules of react is a lot easier when we have a source location corresponding to the value that has changed inappropriately. I didn't see an easy way to track that information in the existing data structures at the point of codegen, so this PR adds locations to identifiers and reactive scopes (the location of a reactive scope is the range of the locations of its included identifiers).

I'm interested if there's a better way to do this that I missed!

[ghstack-poisoned]

Author: mvitousek

.github/ISSUE_TEMPLATE/config.yml

@@ -1,3 +1,4 @@
+blank_issues_enabled: false
 contact_links:
     - name: 📃 Documentation Issue
       url: https://github.com/reactjs/react.dev/issues/new/choose

packages/react-client/src/ReactFlightClient.js

@@ -254,6 +254,7 @@ export type Response = {
   _rowLength: number, // remaining bytes in the row. 0 indicates that we're looking for a newline.
   _buffer: Array<Uint8Array>, // chunks received so far as part of this row
   _tempRefs: void | TemporaryReferenceSet, // the set temporary references can be resolved from
+  _debugRootTask?: null | ConsoleTask, // DEV-only
 };
 
 function readChunk<T>(chunk: SomeChunk<T>): T {
@@ -614,6 +615,7 @@ function getTaskName(type: mixed): string {
 }
 
 function createElement(
+  response: Response,
   type: mixed,
   key: mixed,
   props: mixed,
@@ -697,9 +699,15 @@ function createElement(
         const callStack = buildFakeCallStack(stack, createTaskFn);
         // This owner should ideally have already been initialized to avoid getting
         // user stack frames on the stack.
-        const ownerTask = owner === null ? null : initializeFakeTask(owner);
+        const ownerTask =
+          owner === null ? null : initializeFakeTask(response, owner);
         if (ownerTask === null) {
-          task = callStack();
+          const rootTask = response._debugRootTask;
+          if (rootTask != null) {
+            task = rootTask.run(callStack);
+          } else {
+            task = callStack();
+          }
         } else {
           task = ownerTask.run(callStack);
         }
@@ -1106,6 +1114,7 @@ function parseModelTuple(
     // TODO: Consider having React just directly accept these arrays as elements.
     // Or even change the ReactElement type to be an array.
     return createElement(
+      response,
       tuple[1],
       tuple[2],
       tuple[3],
@@ -1149,6 +1158,14 @@ export function createResponse(
     _buffer: [],
     _tempRefs: temporaryReferences,
   };
+  if (supportsCreateTask) {
+    // Any stacks that appear on the server need to be rooted somehow on the client
+    // so we create a root Task for this response which will be the root owner for any
+    // elements created by the server. We use the "use server" string to indicate that
+    // this is where we enter the server from the client.
+    // TODO: Make this string configurable.
+    response._debugRootTask = (console: any).createTask('"use server"');
+  }
   // Don't inline this call because it causes closure to outline the call above.
   response._fromJSON = createFromJSONCallback(response);
   return response;
@@ -1730,6 +1747,7 @@ function buildFakeCallStack<T>(stack: string, innerCall: () => T): () => T {
 }
 
 function initializeFakeTask(
+  response: Response,
   debugInfo: ReactComponentInfo | ReactAsyncInfo,
 ): null | ConsoleTask {
   if (taskCache === null || typeof debugInfo.stack !== 'string') {
@@ -1745,7 +1763,7 @@ function initializeFakeTask(
   const ownerTask =
     componentInfo.owner == null
       ? null
-      : initializeFakeTask(componentInfo.owner);
+      : initializeFakeTask(response, componentInfo.owner);
 
   // eslint-disable-next-line react-internal/no-production-logging
   const createTaskFn = (console: any).createTask.bind(
@@ -1755,7 +1773,12 @@ function initializeFakeTask(
   const callStack = buildFakeCallStack(stack, createTaskFn);
 
   if (ownerTask === null) {
-    return callStack();
+    const rootTask = response._debugRootTask;
+    if (rootTask != null) {
+      return rootTask.run(callStack);
+    } else {
+      return callStack();
+    }
   } else {
     return ownerTask.run(callStack);
   }
@@ -1776,7 +1799,7 @@ function resolveDebugInfo(
   // We eagerly initialize the fake task because this resolving happens outside any
   // render phase so we're not inside a user space stack at this point. If we waited
   // to initialize it when we need it, we might be inside user code.
-  initializeFakeTask(debugInfo);
+  initializeFakeTask(response, debugInfo);
   const chunk = getChunk(response, id);
   const chunkDebugInfo: ReactDebugInfo =
     chunk._debugInfo || (chunk._debugInfo = []);
@@ -1813,12 +1836,17 @@ function resolveConsoleEntry(
     printToConsole.bind(null, methodName, args, env),
   );
   if (owner != null) {
-    const task = initializeFakeTask(owner);
+    const task = initializeFakeTask(response, owner);
     if (task !== null) {
       task.run(callStack);
       return;
     }
   }
+  const rootTask = response._debugRootTask;
+  if (rootTask != null) {
+    rootTask.run(callStack);
+    return;
+  }
   callStack();
 }