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fix: name the failing key on DefinePlugin typeof evaluation errors - #21503

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claude/pr-20260-review-e6cze3
Jul 25, 2026
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fix: name the failing key on DefinePlugin typeof evaluation errors#21503
alexander-akait merged 1 commit into
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claude/pr-20260-review-e6cze3

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@alexander-akait

@alexander-akait alexander-akait commented Jul 25, 2026

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Summary

Closes #15371. When a DefinePlugin typeof value cannot be evaluated (e.g. an invalid non-stringified string), webpack reported a bare Module parse failed: Unexpected token with no hint of which define caused it. This prefixes the failing define key onto the error so it is actionable. The original error object is reused, so ModuleParseError still renders its code frame — no extra parser.evaluate() calls are added (hot paths untouched) and no stats serialization is changed. Refs #20260 (a perf-safe, narrower take on that closed PR).

What kind of change does this PR introduce?

fix

Did you add tests for your changes?

Yes — test/statsCases/define-plugin-error/ (snapshot of the rendered error) and test/DefinePlugin.unittest.js (covers the string, throwing-runtimeValue, and non-Error throw branches).

Does this PR introduce a breaking change?

No.

If relevant, what needs to be documented once your changes are merged or what have you already documented?

n/a

Use of AI

AI (Claude Code) was used to investigate issue #15371 and the closed PR #20260, reproduce the behavior against a source build, implement this narrower perf-safe version, and write the tests. All changes were reviewed and verified by me.

Copilot AI review requested due to automatic review settings July 25, 2026 12:50
@changeset-bot

changeset-bot Bot commented Jul 25, 2026

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🦋 Changeset detected

Latest commit: 2db2154

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package
Name Type
webpack Patch

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Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

@github-actions

github-actions Bot commented Jul 25, 2026

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This PR is packaged and the instant preview is available (e02f566).

Install it locally:

  • npm
npm i -D webpack@https://pkg.pr.new/webpack@e02f566
  • yarn
yarn add -D webpack@https://pkg.pr.new/webpack@e02f566
  • pnpm
pnpm add -D webpack@https://pkg.pr.new/webpack@e02f566

@codecov

codecov Bot commented Jul 25, 2026

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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.57%. Comparing base (61d4136) to head (2db2154).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files
@@            Coverage Diff             @@
##             main   #21503      +/-   ##
==========================================
- Coverage   93.57%   93.57%   -0.01%     
==========================================
  Files         619      619              
  Lines       73232    73241       +9     
  Branches    21105    21107       +2     
==========================================
+ Hits        68526    68533       +7     
- Misses       4706     4708       +2     
Flag Coverage Δ
css-parsing 25.60% <8.33%> (-0.01%) ⬇️
html5lib 27.06% <8.33%> (-0.01%) ⬇️
integration 89.66% <100.00%> (-0.01%) ⬇️
test262 43.11% <8.33%> (-0.01%) ⬇️
unit 46.33% <8.33%> (-0.01%) ⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

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  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
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Copilot AI review requested due to automatic review settings July 25, 2026 12:55
@alexander-akait
alexander-akait force-pushed the claude/pr-20260-review-e6cze3 branch from ef3de25 to 1af8219 Compare July 25, 2026 12:55

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Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

@codspeed-hq

codspeed-hq Bot commented Jul 25, 2026

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Merging this PR will not alter performance

✅ 216 untouched benchmarks


Comparing claude/pr-20260-review-e6cze3 (2db2154) with main (61d4136)

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The runtimes (bun) failure is unrelated to this change. test/internalSerializables.unittest.js didn't fail an assertion — a jest-worker thread crashed and was force-exited (93,906 passed, 0 assertion failures). This PR adds no serializable and doesn't touch serialization; it only wraps DefinePlugin's typeof evaluation. This is the known Bun/jest-worker flakiness (cf. test/patches/), and it passes on Deno and all Node integration shards — a re-run should clear it.

(codecov/project is still converging as the last coverage shard uploads; codecov/patch is already green — all modified lines are covered.)


Generated by Claude Code

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On the CodSpeed -66.84% memory flag for concatenate-modules (mode-development): this is a measurement artifact, not a regression from this change.

  • CodSpeed's own banner notes BASE and HEAD were measured in different runtime environments, which skews memory comparisons, and the flagged set is unstable across runs (2 regressions incl. devtool-eval on the prior commit, just 1 now).
  • This diff only wraps DefinePlugin's typeof evaluation in a try/catch and adds one module-level helper — it introduces no per-compilation allocation and never runs in the ConcatenatedModule path this benchmark exercises, so it can't move that heap by ~3 MB.
  • The other 183 benchmarks are untouched.

Happy to re-run if a maintainer wants a same-environment comparison.


Generated by Claude Code

@alexander-akait
alexander-akait force-pushed the claude/pr-20260-review-e6cze3 branch from 1af8219 to 3272dec Compare July 25, 2026 13:57
Copilot AI review requested due to automatic review settings July 25, 2026 13:57

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Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

When DefinePlugin cannot evaluate a typeof replacement value (e.g. an
invalid non-stringified string), the parse error now names the offending
define key instead of a bare "Unexpected token". The original error is
reused so ModuleParseError still renders its code frame; no extra
parser.evaluate() calls are added and stats output is unchanged.
@alexander-akait
alexander-akait force-pushed the claude/pr-20260-review-e6cze3 branch from 3272dec to 2db2154 Compare July 25, 2026 14:06
Copilot AI review requested due to automatic review settings July 25, 2026 14:06

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Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

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Types Coverage

Coverage after merging claude/pr-20260-review-e6cze3 into main will be
99.34%
Coverage Report
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@alexander-akait
alexander-akait merged commit e02f566 into main Jul 25, 2026
61 of 62 checks passed
@alexander-akait
alexander-akait deleted the claude/pr-20260-review-e6cze3 branch July 25, 2026 15:09
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more informative error in DefinePlugin

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