Method tryLoadGraphSync

packages/jest-runtime/src/internals/EsmLoader.ts:331–592

(
    rootPath: string,
    rootQuery: string,
    mode: SyncEsmMode,
  )

  // through `requireEsmModule` (sync require entry) or via `loadEsmModule`
  // (the legacy async entry, which first-tries this).
  tryLoadGraphSync(
    rootPath: string,
    rootQuery: string,
    mode: SyncEsmMode,
  ): ESModule | null {
    if (
      this.testState.bailIfTornDown(
        'You are trying to `import` a file after the Jest environment has been torn down.',
      )
    ) {
      return null;
    }

    const registry = this.registries.getActiveEsmRegistry();
    const rootKey = rootPath + rootQuery;

    const cached = registry.get(rootKey);
    if (cached) {
      if (cached instanceof Promise) return null;
      // The legacy `loadEsmModule` source-text branch does `registry.set`
      // while the `SourceTextModule` is still `'unlinked'` (link runs later
      // in `linkAndEvaluateModule`); accessing `.namespace` on a non-evaluated
      // module throws `ERR_VM_MODULE_STATUS`. Surface settled entries
      // (`'evaluated'` / `'errored'`); bail otherwise.
      if (cached.status === 'evaluated') return cached as ESModule;
      if (cached.status === 'errored') throw cached.error;
      return null;
    }

    const context = this.getContext();

    if (this.transformCache.hasMutex(rootKey)) return null;

    const scratch = new Map<string, ScratchEntry>();
    const worklist: Array<WorklistEntry> = [
      {cacheKey: rootKey, modulePath: rootPath},
    ];

    while (worklist.length > 0) {
      const {cacheKey, modulePath} = worklist.pop()!;
      if (scratch.has(cacheKey)) continue;

      // Registry first, mutex second. Same settled-status gate as the root -
      // anything in `'unlinked'` / `'linking'` / `'linked'` / `'evaluating'`
      // is the legacy path mid-flight on this dep. Plugging an unlinked
      // module into the parent's `linkRequests` would fail Node's link
      // cascade; plugging a `'linked'` one would skip its body. Bail.
      const fromRegistry = registry.get(cacheKey);
      if (fromRegistry instanceof Promise) return null;
      if (fromRegistry) {
        if (fromRegistry.status === 'errored') throw fromRegistry.error;
        if (fromRegistry.status !== 'evaluated') return null;
        scratch.set(cacheKey, {
          cacheKey,
          kind: 'synthetic',
          module: fromRegistry,
        });
        continue;