[alexander-akait]

Refs #374.

While webpack builds, the ESLint check gets files in batches of about 80. Under typed linting each batch called signatures() from scratch: it parsed every tsconfig.json again and stat-ed every file of the program again. So one build paid for the whole project once per batch.

The fix

createSigner(graph) returns a signer that one ESLint check instance keeps for its build, which is one compilation (src/check.js:207). Within a build it:

• stats each file and parses each config file once,
• computes the project signature once,
• keeps the signatures of import cycles (strongly connected components) it has already worked out for later batches.

If a config file turns out to have changed, it starts over, as before. signatures(graph, files) stays as a one-batch wrapper.

Measured inside a warm build of the barrel-shaped project from #395 (3,000 modules):

signatures(), main:  38 batches × ~6,000 stat calls, 1.9 s of CPU
signatures(), here:  0.3 s of CPU

warm build, typed ESLint (parserOptions.project) + use: 'typescript'
                                     threads: false          threads on (default)
eslint-webpack-plugin + fork-ts      10.7–11.1 s, 965 MiB    n/a
main                                 13.3–13.7 s, 1,325 MiB  10.3–11.2 s, 850 MiB
this PR                              11.9–12.4 s, 1,320 MiB  11.0–11.2 s, 865 MiB

Memory is the peak memory of the whole process tree, including fork-ts-checker's own process.

What's left with threads: false

About 1.2 s and 350 MiB still separate threads: false from the old plugins. That cost is the TypeScript check itself: 824 ms in createProgram and 310 ms building the incremental state, run on webpack's thread and held in webpack's heap. fork-ts-checker pays roughly the same, but in a separate process alongside the build. That's what threads: false asks for, and the README already says so. With threads on (the default), the plugin matches or beats the old plugins.

Tests

• test/import-graph.test.js adds two tests.
  • One checks that later batches of a build don't read tsconfig.json again. Per-batch signing, as on main, reads it 3 times for the first batch and 7 times after three; the signer stays at 3.
  • The other checks that signing in batches gives the same signatures as signing all files at once.
• Locally, npm run lint passes and the full suite (369 tests) passes, with NODE_PATH unset as before.

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Generated by Claude Code

Summary by CodeRabbit

• Performance
  • Typed-linting files are now read once per build rather than once per batch, reducing repeated work.
  • Configuration and dependency information is reused across batches when possible, while changes to configuration are detected and reflected in results.
  • Signing results remain consistent whether files are processed together or across separate batches.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.69%. Comparing base (8153e2a) to head (31efd31).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #397   +/-   ##
=======================================
  Coverage   99.69%   99.69%           
=======================================
  Files          21       21           
  Lines        6552     6630   +78     
=======================================
+ Hits         6532     6610   +78     
  Misses         20       20           

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[coderabbitai]

No actionable comments were generated in the recent review.

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Reviewing files that changed from the base of the PR and between 99fdaaf and 31efd31.

Files selected for processing: 2

• src/import-graph.js
• test/import-graph.test.js

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Walkthrough

The import graph now provides a reusable signer that caches file and config reads across batches. It recomputes signatures when previously recorded config hashes change. The ESLint check retains the signer for remembered results. Tests cover config reads across batches and compare batched signatures with signatures from a single batch. A patch changeset records the release note.

Priority: Low

Merge Risk: Low · up to 31efd

The change reduces signing work per build. In rare cases an autofix within one build could let a dependent file reuse a stored lint result based on the old contents, and the next build corrects it. This is acceptable to merge with owner awareness.

Pre-merge checks: 5

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title says the change signs typed-lint results once per build instead of once per batch. The raw summary and objectives both describe a build-scoped signer (createSigner) that reuses signature wor…
Docstring Coverage		Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentat…
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Title check

Explanation

The title says the change signs typed-lint results once per build instead of once per batch. The raw summary and objectives both describe a build-scoped signer (createSigner) that reuses signature work across ESLint batches, so the title matches the main change. The title is 71 characters, which is within a reasonable length for a commit-style title, and it is specific enough for a teammate scanning history to understand the primary change.

Full details: Docstring Coverage

Explanation

Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentation-only edits and deletions within surviving functions are included; unchanged diff context and fully deleted functions are excluded. Analyzed 2 functions across 3 files.

Finishing Touches

📝 Generate docstrings

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🧪 Generate unit tests (beta)

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• Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

Warning

Some tools did not complete. Review the errors below.

ESLint

If the error stems from missing dependencies, add them to the package.json file. For unrecoverable errors (e.g., due to private dependencies), disable the tool in the CodeRabbit configuration.

test/import-graph.test.js

Oops! Something went wrong! :(

ESLint: 10.10.0

SyntaxError: Unexpected token ':'
at compileSourceTextModule (node:internal/modules/esm/utils:319:16)
at ModuleLoader.moduleStrategy (node:internal/modules/esm/translators:89:18)
at #translate (node:internal/modules/esm/loader:438:20)
at afterLoad (node:internal/modules/esm/loader:506:29)
at ModuleLoader.loadAndTranslate (node:internal/modules/esm/loader:511:12)
at #getOrCreateModuleJobAfterResolve (node:internal/modules/esm/loader:564:36)
at afterResolve (node:internal/modules/esm/loader:611:52)
at ModuleLoader.getOrCreateModuleJob (node:internal/modules/esm/loader:617:12)
at node:internal/modules/esm/loader:636:32
at TracingChannel.tracePromise (node:diagnostics_channel:370:14)

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Actionable comments posted: 1

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Commits

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• .changeset/sign-once-per-build.md
• src/checks/eslint.js
• src/import-graph.js
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