fix: parse Webpack 5 module maps nested in UMD wrappers

[Menny1337]

Summary

Related to #372.

Webpack 5 UMD output nests its bootstrap IIFE inside the UMD factory. The analyzer previously missed that module map, while empty or unrelated competing IIFEs could also be selected incorrectly.

This change:

• discovers nested zero-argument Webpack bootstrap IIFEs
• ranks candidates using expected module-ID overlap and Webpack runtime structure
• excludes empty module maps
• preserves top-level and legacy parser fallbacks
• computes each asset's module metadata once
• adds Webpack 5 regression fixtures covering empty and decoy IIFEs

A patch Changeset is included.

What kind of change does this PR introduce?

Fix.

Did you add tests for your changes?

Yes. The tests cover unhinted, partially hinted, tied, and non-matching candidate selection, analyzer module-ID plumbing, and single-pass asset-module collection.

Validation:

• npm test -- test/parseUtils.js test/analyzerUtils.js — 27 passed
• npm run build — passed
• npm run test:coverage — 136 passed, 4 skipped
• npm run lint — ESLint, TypeScript, and Prettier passed
• git diff --check — passed

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?

No documentation changes are required. This corrects existing bundle parsing behavior.

Use of AI

GitHub Copilot assisted with reproducing the failure, drafting the implementation and regression tests, and iterating on review feedback.

Human verification: I reviewed every generated change and the complete final diff, verified the behavior against Webpack 5.105.2 output, and ran all validation commands listed above. The patch also received independent review before publication. I understand the implementation and remain responsible for the contribution.

[changeset-bot]

🦋 Changeset detected

Latest commit: eba7f74

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

This PR includes changesets to release 1 package

Name	Type
webpack-bundle-analyzer	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: Copilot / name: Copilot (eeb1f0f, fee1368)
• ✅ login: Menny1337 / name: Menny Mezamer-Tov (eeb1f0f, fee1368)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.58%. Comparing base (24e3f77) to head (eba7f74).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #733      +/-   ##
==========================================
+ Coverage   76.39%   78.58%   +2.19%     
==========================================
  Files          17       17              
  Lines        1004     1060      +56     
  Branches      360      383      +23     
==========================================
+ Hits          767      833      +66     
+ Misses        207      199       -8     
+ Partials       30       28       -2     

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[valscion]

Looks good to me! Can you take a look at the coverage report? To my eyes it looks like some branches you added are lacking code coverage. Ideally we'd have more tests that verify a real webpack bundle parses correctly without having to pass any custom optiona ourselves in test.

I'm ready to merge this once the coverage question has been dealt with

[valscion]

Looks like that #723 getting merged also caused a merge conflict here which needs to be resolved.

[Menny1337]

Addressed the coverage feedback in c24d570 and eba7f74.

• added a generated Webpack 5 UMD fixture exercised by the standard no-options parser test harness
• verified upstream main returns no modules for that fixture while this branch returns module IDs 447 and 956
• covered empty/decoy candidates, nested member access, legacy top-level fallback, matching non-runtime candidates, child assets, and modules without IDs
• retained Improve analyzer performance for bundles with many assets #723's chunk-index optimization and single-pass root asset module selection
• measured every production line and branch added by this PR at 100% coverage (analyzer.js: 11/11 lines, 8/8 branches; parseUtils.js: 58/58 lines, 60/60 branches)

The targeted parser/analyzer tests, lint/type/format checks, and production build pass locally.

[Menny1337]

Thanks for the review, @valscion. I’ve rebased onto the latest main, resolved the #723 conflict, and expanded the regression coverage.

The tests now include a generated Webpack 5 UMD bundle parsed through the normal no-options path, plus candidate-selection edge cases. All production lines and branches added by this PR have 100% coverage.

The PR is conflict-free and ready for another look when you have time.

[valscion]

Looks good to me, thanks for the contribution!