refactor: replace unknown and EXPECTED_ANY with precise types across lib - #22742

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• .changeset/400-precise-public-types.md

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• .changeset/400-precise-public-types.md

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This pull request replaces broad or indirect types with specific types across webpack configuration, parsers, minifier code, runtimes, and supporting modules. Most edits affect annotations and assertions; the summaries report unchanged runtime behavior.

Changes: Type precision migration

Layer / File(s)	Summary
Compiler and configuration types .changeset/*, lib/Compilation.js, lib/config/*, lib/define/EnvironmentPlugin.js, lib/define/DefinePlugin.js, lib/module/NormalModuleFactory.js	Stats, CLI flags, minimizer options, compiler values, and configuration defaults receive more specific types. The changeset updates its description of the type-migration scope.
Parser and syntax-tree types lib/asset/WebManifestParser.js, lib/css/*, lib/html/syntax-parser.js, lib/javascript/syntax-parser.js	Parser assertions and syntax-tree values use specific node, token, callback, and value types. Parser and tree construction behavior is unchanged.
Parser integrations and AST consumers lib/dependencies/commonjs/*, lib/dependencies/context/*, lib/dependencies/css/*, lib/javascript/JavascriptParser.js, lib/javascript/BasicEvaluatedExpression.js, lib/javascript/ScopeAnalyzer.js	AST checks, traversal values, parser state, scope values, and cached build information receive more specific types.
Minifier and printer type shapes lib/javascript/syntax-printer.js	Transforms, evaluation, compression, and printing use concrete node, option, callback, and result types.
Runtime, graph, and hook types lib/debug/ProfilingPlugin.js, lib/dependencies/esm/ESMExportExpressionDependency.js, lib/externals/ExternalsPlugin.js, lib/graph/buildChunkGraph.js, lib/hmr/*	HMR promise and chunk-state types, graph tuple assertions, hook structures, external fragments, and serialization-context tuples are made more specific.
Loader and source-processing types lib/loaders/LoaderRunner.js, lib/schemes/VirtualUrlPlugin.js, lib/util/SourceProcessor.js, lib/performance/*, lib/optimize/InlineExports.js, lib/output/CopyPlugin.js	Loader contexts, visitor registrations, AST traversal values, and cache keys receive more specific types.
Serialization, errors, and shared types lib/errors/*, lib/serialization/*, lib/stats/DefaultStatsPrinterPlugin.js, lib/module/Module.js, lib/node/nodeConsole.js, lib/util/*, lib/index.js	Error inputs, serialized causes, tuple exhaustion, utility annotations, and related casts use narrower or generic types. Runtime logic remains unchanged in the described edits.

Possibly related PRs

• webpack/webpack#21800: Replaces custom EXPECTED_* declarations with native types across overlapping files and type-annotation surfaces.

Suggested labels: breaking-change

No actionable merge-blocking issue remains in the supplied review scope.

Pre-merge checks: 3 · 1

Failed checks: 1 inconclusive

Check name	Status	Explanation	Resolution
Title check		The title uses valid Conventional Commit syntax with the allowed type refactor and clearly describes the type-only changes. The branch prefix is not provided, so the required type-to-branch-prefix m…	Provide the branch name or confirm that its prefix is refactor. If the prefix differs, update the title or branch to match.

Passed checks: 3 passed

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
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 uses valid Conventional Commit syntax with the allowed type refactor and clearly describes the type-only changes. The branch prefix is not provided, so the required type-to-branch-prefix match cannot be verified.

Resolution

Provide the branch name or confirm that its prefix is refactor. If the prefix differs, update the title or branch to match.

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#!/bin/bash
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gh api --method DELETE repos/webpack/webpack/issues/22742/labels/breaking-change
gh pr view 22742 --repo webpack/webpack --json labels --jq '.labels | map(.name)'

Length of output: 3463

Learnt from: alexander-akait
URL: https://github.com/webpack/webpack/pull/22742

Timestamp: 2026-10-17T11:16:40.310Z
Learning: In webpack/webpack, type refinements that replace any or unknown with the types webpack actually accepts or passes are shipped as patches when they preserve documented behavior. Do not classify such changes as breaking solely because unsupported values now produce type errors. Apply the breaking-change label when changes to the public API, defaults, or emitted output require a semver-major release.

Note: Learnings are effective only in the context of similar code segments. To apply general coding guidelines, please configure review instructions. You can manage existing learnings in the app.

@@           Coverage Diff           @@
##             main   #22742   +/-   ##
=======================================
  Coverage   96.45%   96.45%           
=======================================
  Files         778      778           
  Lines      136310   136312    +2     
  Branches    46006    46005    -1     
=======================================
+ Hits       131476   131479    +3     
+ Misses       4834     4833    -1     

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System calls cannot be consistently instrumented, so they are not included in the measure, which understates the real cost. Please switch to the Walltime instrument to accurately measure system calls.

Measurement and system calls

• benchmark "cache-filesystem-cold", scenario '{"name":"mode-development","mode":"development"}'
• benchmark "cache-filesystem", scenario '{"name":"mode-production","mode":"production"}'
• benchmark "no-concatenation", scenario '{"name":"mode-development","mode":"development"}'
• benchmark "context-esm", scenario '{"name":"mode-development-rebuild","mode":"development","watch":true}'
• benchmark "react", scenario '{"name":"mode-development-rebuild","mode":"development","watch":true}'
• benchmark "asset-modules-source", scenario '{"name":"mode-development-rebuild","mode":"development","watch":true}'
• benchmark "devtool-eval-source-map", scenario '{"name":"mode-development-rebuild","mode":"development","watch":true}'
• benchmark "no-exports-analysis", scenario '{"name":"mode-development","mode":"development"}'
• benchmark "devtool-source-map", scenario '{"name":"mode-development-rebuild","mode":"development","watch":true}'
• benchmark "asset-modules-inline", scenario '{"name":"mode-development-rebuild","mode":"development","watch":true}'
• …and 98 more

The flamegraph could not be generated because too much time was spent in runtime internals, making the visualization not useful for performance analysis.

• unit benchmark "scope-analyzer-unit", analyze 'lodash.js'
• benchmark "context-esm", scenario '{"name":"mode-production","mode":"production"}'
• benchmark "common-libs", scenario '{"name":"mode-production","mode":"production"}'
• unit benchmark "scope-analyzer-unit", analyze 'three.module.js'
• benchmark "three-long", scenario '{"name":"mode-production","mode":"production"}'
• benchmark "asset-modules-inline", scenario '{"name":"mode-production","mode":"production"}'
• benchmark "asset-modules-source", scenario '{"name":"mode-production","mode":"production"}'
• benchmark "wasm-modules-sync", scenario '{"name":"mode-production","mode":"production"}'
• benchmark "css-modules", scenario '{"name":"mode-production","mode":"production"}'
• benchmark "no-exports-analysis", scenario '{"name":"mode-production","mode":"production"}'
• …and 18 more