perf(move-file): cache index file export analysis #316

LayZeeDK · 2025-10-29T20:52:40Z

perf(move-file): cache index file export analysis (#161)

Summary
Adds an index exports cache to avoid reparsing entrypoint (index) files for each export check during move-file operations. Replaces repeated regex scans with a cached, content-keyed extraction of export/re-export specifiers.

Implementation

New index-exports-cache.ts with:
- getIndexExports(tree, indexPath): regex parses export/re-export statements once per content snapshot
- Content snapshot stored to auto-invalidate when file content changes via treeReadCache
- clear / invalidate helpers (prepared for future wiring)
isFileExported now consults cache instead of building a fresh RegExp per entrypoint scan
Normalizes stored specifiers (ensures leading ./) for consistent lookup
No changes to public generator API; all tests unchanged

Benchmarks (ran 2025-10-29T20:53:33Z, updated at 2025-10-29T20:55:40.852Z)
Baseline (before):

Export detection: 56,768 ops/sec ±2.09%
Export addition: 61,458 ops/sec ±1.81%
Export removal: 56,077 ops/sec ±1.82%

Updated (after):

Export detection: 62,156 ops/sec ±1.66% (+~9.5%)
Export addition: 61,446 ops/sec ±1.30% (~parity)
Export removal: 62,213 ops/sec ±4.02% (+~11%)

Net Effect

Export presence checks (dominant path) show ~9–11% throughput improvement.
No regressions measured.
All 770 tests pass; lint and formatting pass.

Risk / Mitigation

Cache invalidation leverages existing treeReadCache invalidation when files are written; content snapshot comparison prevents stale data if file changes without explicit invalidation.
Limited scope: only read paths; write logic unaffected.

Follow-ups (optional)

Expose and wire clearIndexExportsCache() into global cache clearing utilities.
Expand regex to capture additional export patterns if needed (e.g., default export forwarding aliases).

Closes #161.

Copilot

Pull Request Overview

Adds a caching mechanism for index file export analysis to improve performance in move-file operations by avoiding repeated regex parsing of entrypoint files.

Introduces an index exports cache that stores parsed export/re-export specifiers with content-based invalidation
Replaces per-call regex compilation with cached export analysis for ~9-11% performance improvement
Maintains existing API compatibility with no changes to public interfaces or test behavior

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
index-exports-cache.ts	New cache implementation with regex-based export parsing and content-keyed invalidation
is-file-exported.ts	Updated to use cached export analysis instead of inline regex compilation
updated-export-bench.txt	Performance benchmark results showing improved throughput
baseline-export-bench.txt	Baseline performance metrics for comparison

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

Copilot · 2025-10-29T21:04:36Z

packages/workspace/src/generators/move-file/export-management/index-exports-cache.ts

+  for (const spec of reexports) {
+    const withoutExt = spec.replace(/\.(ts|tsx|js|jsx)$/i, '');
+    // Ensure stored paths are normalized to start with './'
+    const normalized =
+      withoutExt.startsWith('./') || withoutExt.startsWith('../')
+        ? withoutExt
+        : `./${withoutExt}`;
+    exports.add(normalized);
+  }


The logic adds reexports to the exports set, which conflates two different types of exports. The reexports should remain in the reexports set, and exports should contain actual local exports from the file.

Suggested change

for (const spec of reexports) {

const withoutExt = spec.replace(/\.(ts|tsx|js|jsx)$/i, '');

// Ensure stored paths are normalized to start with './'

const normalized =

withoutExt.startsWith('./') || withoutExt.startsWith('../')

? withoutExt

: `./${withoutExt}`;

exports.add(normalized);

}

// Note: Do not add reexports to exports. Exports should only contain actual local exports.

// If needed, add logic here to capture local exports (e.g., export { foo, bar };) in the future.

Copilot · 2025-10-29T21:04:36Z

packages/workspace/src/generators/move-file/export-management/index-exports-cache.ts

+
+  // Match: export * from './path';  OR export { ... } from './path'; OR export {default as X} from './path';
+  const reExportPattern =
+    /export\s+(?:\*|\{[^}]+\})\s+from\s+['"](\.\.?\/[^'";]+)['"];?/g;


The regex pattern allows paths that don't start with './' or '../' by using \.\.?\/ which makes the second dot optional. This could match invalid paths like ./x incorrectly. The pattern should be (\.\.?\/[^'";]+) or more specifically (\.(?:\.\/|\/)[^'";]+) to properly match relative paths.

Suggested change

/export\s+(?:\*|\{[^}]+\})\s+from\s+['"](\.\.?\/[^'";]+)['"];?/g;

/export\s+(?:\*|\{[^}]+\})\s+from\s+['"](\.(?:\.\/|\/)[^'";]+)['"];?/g;

Copilot · 2025-10-29T21:04:37Z

packages/workspace/src/generators/move-file/export-management/index-exports-cache.ts

+  for (const spec of reexports) {
+    const withoutExt = spec.replace(/\.(ts|tsx|js|jsx)$/i, '');


The file extension removal logic duplicates functionality that likely exists elsewhere in the codebase (e.g., removeSourceFileExtension that's imported in the other file). Consider extracting this to a shared utility or reusing existing functionality.

LayZeeDK · 2025-10-29T21:06:47Z

Applied review feedback:

Separated reexports from exports (no conflation).
Added clarifying comments and left exports empty until local export parsing is implemented.
Updated isFileExported to rely solely on reexports.

All tests & lint pass.

Implementing index export cache to parse local exports in addition to re-exports ## Plan - [x] Create IndexExports type and interface in export-management - [x] Create getIndexExports function to parse local exports using AST - [x] Update isFileExported to use the new cache system - [x] Add comprehensive unit tests for getIndexExports - [x] Add benchmark tests for performance validation - [x] Update existing tests to cover local export scenarios - [x] Run linting, build, and all tests - [x] Format code - [x] Update documentation - [x] Address code review feedback - [x] Update JSDoc comments to reflect cache usage ## Recent Changes Updated documentation in `isFileExported()` to clarify: - Function now uses the index exports cache system - Cache parses local declarations but function only checks re-exports - This addresses review feedback about outdated documentation The distinction is important: `isFileExported()` checks if a **file** is re-exported (e.g., `export * from './lib/utils'`), not if **symbols** from that file are present as local exports in the index.  <details> <summary>Original prompt</summary> ---- *This section details on the original issue you should resolve* <issue_title>feat(move-file): parse local exports in index export cache</issue_title> <issue_description>## Summary Enhance the index exports cache to parse and record *local* export declarations in entrypoint (index) files in addition to existing re-export ("export ... from") patterns. Currently `getIndexExports()` only captures reexports and leaves `exports` empty, forcing callers (e.g. `isFileExported`) to rely solely on `reexports`. This prevents accurate detection of locally defined exports (e.g. `export { foo, bar }`, `export const X = ...`, `export function fn() {}`, `export class C {}`, and `export default ...`). Supporting these will improve correctness of move-file validation (unexported dependency checks, alias conversions) and reduce false warnings. ## Motivation / Problem When a project’s public surface is defined via local declarations in `index.ts` rather than re-exporting from leaf modules, the current cache misses them. As a result: - `isFileExported()` incorrectly reports a file as unexported if it’s aggregated via local declarations copied into the index. - Move-file generator may warn about supposedly unexported relative dependencies. - Potential future optimizations (e.g., differentiating default vs named exports) are blocked. ## Scope Add robust parsing of local export declarations for TypeScript/JavaScript index files, keeping the lightweight approach (regex or jscodeshift) while maintaining performance. Preserve separation between `exports` and `reexports` (per review feedback in PR #316). ## Proposed Design 1. Reuse existing AST caching (jscodeshift + `astCache`) for structural accuracy while minimizing parse cost. 2. Collect and normalize local export specifiers: - Named declarations: `export const A`, `export function b`, `export class C`, `export interface D`, `export type E`, `export enum F`. - Named list: `export { a, b as c }` (without `from`). - Default exports: `export default X`, `export default function() {}`, `export default class {}`. 3. Represent cache structure: ```ts interface IndexExports { exports: Set<string>; // local named export identifiers (normalized) reexports: Set<string>; // existing re-export specifiers ('./lib/util') defaultExport?: string; // identifier or synthetic marker ('<anonymous>') if unnamed default } ``` 4. Normalization Rules: - Local identifiers stored exactly as defined (no extension logic needed). - Anonymous default exports mapped to a sentinel (e.g. `<default>` or `<anonymous-default>`). 5. Backwards compatibility: existing callers using `reexports` remain unchanged; add helper `isLocalSymbolExported(name)` if needed later. 6. Performance Strategy: - Parse AST once via `astCache.getAST`; fall back to regex only if AST unavailable. - Skip expensive symbol resolution—pure syntactic discovery. - Maintain content snapshot invalidation (existing logic). 7. Update `isFileExported` logic: - If import specifier points to a file path: keep current re-export check. - If validation wants to infer export of an internal symbol (future), can consult `exports` set. ## Tasks - [ ] Extend `IndexExports` interface (add `defaultExport` field). - [ ] Implement local export parsing function (`collectLocalExports(ast): { names: Set<string>; default?: string }`). - [ ] Integrate parsing into `getIndexExports` (only when content contains `export`). - [ ] Add unit tests covering: - Basic named exports (const/function/class/interface/type/enum). - Named list / alias exports (with `as`). - Default exports (named and anonymous). - Mixed local + re-exports in same file. - Empty index file (returns empty sets, undefined default). - Cache hit behavior (content unchanged). - Cache invalidation (content change updates sets). - [ ] Update `is-file-exported.spec.ts` to include a scenario with local declarations. - [ ] Add benchmark cases to `export-management.bench.ts` for local export detection (ensure negligible regression; target <5% throughput impact). - [ ] Update PR/Documentation: mention difference between local exports and reexports. ## Acceptance Criteria - All new tests pass; existing 770 tests remain green. - Benchmarks show <5% performance degradation for export detection suite or an offsetting improvement if AST parsing reduces regex overhead. - `isFileExported` correctly returns true for files represented by local declarations (when those files exist or are logically aggregated). - No conflation between `exports` and `reexports`; clear docs in `index-exports-cache.ts`. ## Performance Considerations - AST parsing is already cached; incremental cost is node filtering for export declarations. - Provide fallback to fast regex ONLY if AST is unavailable (e.g., parse error). - Keep operations allocation-light (pre-size arrays where possible, avoid repeated string normaliz... </details> - Fixes #317  --- 💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more [Copilot coding agent tips](https://gh.io/copilot-coding-agent-tips) in the docs.

LayZeeDK changed the title ~~perf(move-file): cache index file export analysis (#161)~~ perf(move-file): cache index file export analysis Oct 29, 2025

LayZeeDK added 3 commits October 29, 2025 21:00

perf(move-file): cache index file export analysis (#161)

ff7458e

chore: address review feedback (index exports cache)

d0358cd

refactor(move-file): clean up cache invalidation for index exports

a188b59

github-actions bot force-pushed the feat/161-index-exports-cache branch from 70f97e9 to a188b59 Compare October 29, 2025 21:00

LayZeeDK requested a review from Copilot October 29, 2025 21:03

Copilot AI reviewed Oct 29, 2025

View reviewed changes

fix(move-file): address review feedback on index export cache separation

6908df5

LayZeeDK mentioned this pull request Oct 29, 2025

fix(move-file): parse local exports in index export cache #317

Closed

7 tasks

Copilot AI mentioned this pull request Oct 29, 2025

fix(move-file): parse local exports in index export cache #318

Merged

18 tasks

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Uh oh!

perf(move-file): cache index file export analysis #316

perf(move-file): cache index file export analysis #316

Uh oh!

LayZeeDK commented Oct 29, 2025 •

edited

Loading

Uh oh!

Copilot AI left a comment

Uh oh!

Copilot AI Oct 29, 2025

Uh oh!

Copilot AI Oct 29, 2025

Uh oh!

Copilot AI Oct 29, 2025

Uh oh!

LayZeeDK commented Oct 29, 2025 •

edited

Loading

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

	/export\s+(?:\*\|\{[^}]+\})\s+from\s+['"](\.\.?\/[^'";]+)['"];?/g;
	/export\s+(?:\*\|\{[^}]+\})\s+from\s+['"](\.(?:\.\/\|\/)[^'";]+)['"];?/g;

		for (const spec of reexports) {
		const withoutExt = spec.replace(/\.(ts\|tsx\|js\|jsx)$/i, '');

Uh oh!

perf(move-file): cache index file export analysis #316

Are you sure you want to change the base?

perf(move-file): cache index file export analysis #316

Uh oh!

Conversation

LayZeeDK commented Oct 29, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull Request Overview

Reviewed Changes

Uh oh!

Copilot AI Oct 29, 2025

Choose a reason for hiding this comment

Uh oh!

Copilot AI Oct 29, 2025

Choose a reason for hiding this comment

Uh oh!

Copilot AI Oct 29, 2025

Choose a reason for hiding this comment

Uh oh!

LayZeeDK commented Oct 29, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

LayZeeDK commented Oct 29, 2025 •

edited

Loading

LayZeeDK commented Oct 29, 2025 •

edited

Loading