Return all files from getFilesAffectedBy when a changed file affects global scope

[martijnwalraven]

Fixes #4664

This is a 6.0/7.0 behavior difference in --build/--incremental
invalidation (in-scope per CONTRIBUTING's bridge-release policy).

What

When a changed file affectsGlobalScope, getFilesAffectedBy now returns
the all-files-excluding-default-library set — the set it already computed and
cached — instead of falling through to the reverse-reference walk. This is
Strada's behavior: getFilesAffectedByUpdatedShapeWhenModuleEmit
(src/compiler/builderState.ts) returns
getAllFilesExcludingDefaultLibraryFile(...) for a global-scope shape
change.

Why

getFilesAffectedBy set hasAllFilesExcludingDefaultLibraryFile and primed
the all-files cache on a global-scope change, but still returned only the
changed file plus its reverse closure bounded by unchanged .d.ts signatures.
handleDtsMayChangeOfAffectedFile takes an early return for every affected
file when that flag is set, skipping the reverse-referencedBy invalidation
that removes dependents' cached semantic diagnostics. Strada's equivalent
early return (src/compiler/builder.ts, handleDtsMayChangeOfAffectedFile)
is safe only because its affected set is all files; tsgo kept the early
return but dropped the all-files set.

Consequences on main (see linked issue for a CLI repro and mechanism detail):

• a lone global-scope .d.ts content change does not re-check files that use
  the global without importing the changed module — the incremental build
  stays green while a clean build errors;
• because the flag is handler-global, one global-scope file in a changed
  batch (the shape of a package-manager dependency bump) suppresses dependent
  invalidation for every other changed file in that batch;
• the buildinfo then records the affected files as fully-checked-clean
  (absence of a semanticDiagnosticsPerFile entry), so the false green is
  durable across subsequent builds.

Test coverage

Three new tsbuild/dependencyUpdate scenarios in
internal/execute/tsctests/tscbuild_test.go:

• rebuilds transitive dependents when dependency update batch includes a global scope change — dep-A breaking change + dep-B declare global
  change in one batch; the break surfaces in a consumer connected to dep-A
  only through a module whose .d.ts signature does not change; includes a
  no-change follow-up edit showing durability. Failed on unmodified main via
  the harness's incremental-vs-clean diff (incremental missed TS2366).
• rebuilds transitive dependents when dependency update batch has no global scope change — control arm; behaved correctly before and after.
• rebuilds files using globals when global scope dependency is updated —
  lone global-scope content change violating a non-importing user. Failed on
  unmodified main (incremental missed TS2322).

Baseline impact

15 existing baselines change, uniformly the intended class: after a
global-scope file changes, the other files are now refreshed — recomputed
.d.ts signatures (*refresh* / (computed .d.ts) in program baselines),
cached diagnostics dropped, and files queued for full emit
(affectedFilesPendingEmit gains the sibling files; same-content rewrites
appear in output listings):

• tsc/incremental/when-global-file-is-added,-the-signatures-are-updated —
  the scenario's titular signatures are now actually updated for sibling
  files.
• tsc|tsbuild|tsbuildWatch/noEmit/*-with-incremental-as-modules (12 files)
  — these scenarios edit a.ts into a non-module (global) file mid-scenario;
  b.ts is now refreshed and queued for emit when that happens.
• tsc/noEmitOnError/when-declarationMap-changes,
  tsbuildWatch/noEmit/does-not-go-in-loop-when-watching-... — same class
  (the watch scenario's actual concern, not looping, is unchanged).

Performance note: a global-scope change now invalidates and re-checks all
non-library files, like Strada. The all-files set is computed once per
build (cached on the snapshot), and per-file handling stays on the existing
early-return path (removeSemanticDiagnosticsOf + signature update), so the
cost profile matches Strada's for the same transition; builds with no
global-scope change in the batch are unaffected.

Validation

• go test ./internal/execute/... — green.
• go test ./... — green (macOS; TypeScript-submodule-gated tests skipped —
  submodule not cloned locally).
• CLI three-way check on the linked issue's repro: typescript@6.0.3 errors
  on the incremental rebuild, unmodified main exits 0 silently, this branch
  errors identically to 6.0 and to a clean build.

Disclosure

Per CONTRIBUTING's AI-assistance policy: this patch was authored with an AI
coding agent (Claude Code). I have read and understood the change, chose this
specific issue myself, and will shepherd it through review personally.

[Copilot]

Pull request overview

Aligns incremental/build invalidation with TypeScript by rechecking all non-default-library files after a global-scope shape change.

Changes:

• Returns the cached all-files affected set for global changes.
• Adds dependency-update regression and control scenarios.
• Updates affected incremental, build, and watch baselines.

Reviewed changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
internal/execute/incremental/affectedfileshandler.go	Returns all affected non-library files.
internal/execute/tsctests/tscbuild_test.go	Adds three regression scenarios.
testdata/baselines/reference/tsc/noEmitOnError/when-declarationMap-changes.js	Updates invalidation baseline.
testdata/baselines/reference/tsc/noEmit/syntax-errors-with-incremental-as-modules.js	Updates incremental syntax-error baseline.
testdata/baselines/reference/tsc/noEmit/semantic-errors-with-incremental-as-modules.js	Updates semantic-error baseline.
testdata/baselines/reference/tsc/noEmit/dts-errors-without-dts-enabled-with-incremental-as-modules.js	Updates declaration-error baseline.
testdata/baselines/reference/tsc/noEmit/dts-errors-with-incremental-as-modules.js	Updates declaration-emit baseline.
testdata/baselines/reference/tsc/incremental/when-global-file-is-added,-the-signatures-are-updated.js	Records refreshed global signatures.
testdata/baselines/reference/tsbuildWatch/noEmit/syntax-errors-with-incremental-as-modules.js	Updates watch syntax-error baseline.
testdata/baselines/reference/tsbuildWatch/noEmit/semantic-errors-with-incremental-as-modules.js	Updates watch semantic-error baseline.
testdata/baselines/reference/tsbuildWatch/noEmit/dts-errors-without-dts-enabled-with-incremental-as-modules.js	Updates watch declaration-error baseline.
testdata/baselines/reference/tsbuildWatch/noEmit/dts-errors-with-incremental-as-modules.js	Updates watch declaration-emit baseline.
testdata/baselines/reference/tsbuildWatch/noEmit/does-not-go-in-loop-when-watching-when-no-files-are-emitted-with-incremental.js	Records additional refreshed file.
testdata/baselines/reference/tsbuild/noEmit/syntax-errors-with-incremental-as-modules.js	Updates build syntax-error baseline.
testdata/baselines/reference/tsbuild/noEmit/semantic-errors-with-incremental-as-modules.js	Updates build semantic-error baseline.
testdata/baselines/reference/tsbuild/noEmit/dts-errors-without-dts-enabled-with-incremental-as-modules.js	Updates build declaration-error baseline.
testdata/baselines/reference/tsbuild/noEmit/dts-errors-with-incremental-as-modules.js	Updates build declaration-emit baseline.
testdata/baselines/reference/tsbuild/dependencyUpdate/rebuilds-transitive-dependents-when-dependency-update-batch-includes-a-global-scope-change.js	Covers mixed dependency updates.
testdata/baselines/reference/tsbuild/dependencyUpdate/rebuilds-transitive-dependents-when-dependency-update-batch-has-no-global-scope-change.js	Adds the control scenario.
testdata/baselines/reference/tsbuild/dependencyUpdate/rebuilds-files-using-globals-when-global-scope-dependency-is-updated.js	Covers non-importing global consumers.

[martijnwalraven]

@microsoft-github-policy-service agree