fix(javascript): yield inside semantic analysis and large projection passes (#1542)

* fix(javascript): yield inside semantic analysis and large projection passes

After #1525 the longest event-loop blocks were single stages on very large
files: semantic analysis of Obsidian's 3.7 MB app.js ran 5.8 s in one piece,
and its object projection 1.8 s.

- analyzeParsedJavaScriptSemanticsSteps yields between the analysis phases
  and between the eight derived collectors; the synchronous function drains
  it, so results are unchanged.
- Per-file analysis yields between open-receiver classification and static
  analysis and drives the semantic steps.
- Semantic node creation, definitions and references, and the object and
  frontier passes yield every 64 items. Node creation keeps source order,
  which the per-file node budget depends on.

On obsidian.asar the longest block falls from 5,355 ms to 907 ms with the
same total time (40.6 s to 39.5 s). Graph IDs and complete result digests
match main on five inputs. Remaining blocks up to about 0.9 s are single
AST traversal passes inside the analyzers.

Refs #1462

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* refactor(javascript): drop the unused synchronous derived-semantics wrapper

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

src/domain/javascript/javascriptSemanticAnalysis.ts

@@ -38,7 +38,7 @@ import {
   collectSemanticReturns,
   resolveSemanticModuleCallables,
 } from "./javascriptSemanticReturns.js";
-import { collectJavaScriptDerivedSemantics } from "./javascriptSemanticDerivedAnalysis.js";
+import { collectJavaScriptDerivedSemanticsSteps } from "./javascriptSemanticDerivedAnalysis.js";
 import { range } from "./javascriptStaticAnalysisHelpers.js";
 import { propertyName } from "./javascriptAstValues.js";
 import { semanticCoverage } from "./javascriptSemanticCoverage.js";
@@ -107,18 +107,40 @@ export const analyzeParsedJavaScriptReferences = (
 export const analyzeParsedJavaScriptSemantics = (
   file: ParsedJavaScriptSource,
 ): JavaScriptSemanticIr => {
+  const steps = analyzeParsedJavaScriptSemanticsSteps(file);
+  for (;;) {
+    const step = steps.next();
+    if (step.done === true) return step.value;
+  }
+};
+
+/**
+ * Recover semantics from a parsed artifact with a yield between analysis
+ * phases, so a caller can serve control messages within one large file.
+ * Each phase completes before the next starts; results equal the synchronous
+ * form.
+ */
+export function* analyzeParsedJavaScriptSemanticsSteps(
+  file: ParsedJavaScriptSource,
+): Generator<void, JavaScriptSemanticIr> {
   const state = createState(file.program);
   collectDefinitions(file.program, state);
+  yield;
   collectSemanticMemberMutations(file.program, state);
+  yield;
   traverseJavaScriptAst(file.program, {
     enter: (node) => collectSemanticModuleLink(node, state),
   });
+  yield;
   const references = collectSemanticReferences(file.program, state);
+  yield;
   const parserPartial = file.errors.length > 0;
   const bindings = immutableSemanticBindings(state);
+  yield;
   const callables = collectSemanticReturns(file.program, state, parserPartial);
+  yield;
   const moduleLinks = resolveSemanticModuleCallables(state, callables);
-  const derived = collectJavaScriptDerivedSemantics(
+  const derived = yield* collectJavaScriptDerivedSemanticsSteps(
     file.program,
     state,
     callables,
@@ -154,7 +176,7 @@ export const analyzeParsedJavaScriptSemantics = (
       "Cross-function mutation and dynamic property resolution remain unknown.",
     ],
   };
-};
+}
 
 /** Receiver identity facts for the overloaded `.open` syntax only. */
 export type JavaScriptOpenReceiverFact =

src/domain/javascript/javascriptSemanticAnalysisSteps.test.ts

@@ -0,0 +1,34 @@
+import { expect, it } from "vitest";
+
+import {
+  analyzeParsedJavaScriptSemantics,
+  analyzeParsedJavaScriptSemanticsSteps,
+} from "./javascriptSemanticAnalysis.js";
+import { parseJavaScriptSource } from "./javascriptSourceParser.js";
+
+const source = `
+import { readFile } from "node:fs";
+const shared = { token: "TOKEN" };
+export function load(path) {
+  return new Promise((resolve) => setTimeout(() => resolve(readFile(path)), 1));
+}
+export const box = { get() { return shared; } };
+box.get().value = process.env.MODE ?? "default";
+`;
+
+it("yields between semantic phases and returns the synchronous result (#1462)", () => {
+  const parsed = parseJavaScriptSource(source, "main.js");
+  if (parsed === null) throw new Error("Expected parsed source");
+  const steps = analyzeParsedJavaScriptSemanticsSteps(parsed);
+  let yields = 0;
+  let step = steps.next();
+  while (step.done !== true) {
+    yields += 1;
+    step = steps.next();
+  }
+  // Every top-level phase and derived collector is a separate step.
+  expect(yields).toBeGreaterThanOrEqual(13);
+  const reparsed = parseJavaScriptSource(source, "main.js");
+  if (reparsed === null) throw new Error("Expected parsed source");
+  expect(step.value).toEqual(analyzeParsedJavaScriptSemantics(reparsed));
+});

src/domain/javascript/javascriptSemanticDerivedAnalysis.ts

@@ -36,43 +36,54 @@ type DerivedSemanticAnalysis = Pick<
 >;
 
 /** Compose bounded semantic passes after lexical definitions are available. */
-export const collectJavaScriptDerivedSemantics = (
+/**
+ * Collect derived semantics with a yield between collectors. Each collector
+ * completes before the next starts, so results equal the synchronous form.
+ */
+export function* collectJavaScriptDerivedSemanticsSteps(
   program: t.Program,
   state: JavaScriptSemanticAnalysisState,
   callables: readonly JavaScriptSemanticCallable[],
   parserPartial: boolean,
-): DerivedSemanticAnalysis => {
+): Generator<void, DerivedSemanticAnalysis> {
   const calls = collectJavaScriptSemanticCalls(program, state, callables);
+  yield;
   const promiseOperations = collectJavaScriptSemanticPromises(
     program,
     state,
     callables,
   );
+  yield;
   const asyncEffects = collectJavaScriptSemanticAsyncEffects(
     program,
     state,
     callables,
   );
+  yield;
   const childProcesses = collectJavaScriptSemanticChildProcesses(
     program,
     state,
     callables,
   );
+  yield;
   const dataEffects = collectJavaScriptSemanticDataEffects(
     program,
     state,
     callables,
   );
+  yield;
   const resourceOperations = collectJavaScriptSemanticResources(
     program,
     state,
     callables,
   );
+  yield;
   const objectOperations = collectJavaScriptSemanticObjects(
     program,
     state,
     callables,
   );
+  yield;
   const functionFingerprints = collectJavaScriptSemanticFingerprints({
     state,
     callables,
@@ -96,4 +107,4 @@ export const collectJavaScriptDerivedSemantics = (
     objectOperations,
     functionFingerprints,
   };
-};
+}