Content mappers round 2

[Andrew Branch (andrewbranch)]

This finishes out microsoft/typescript-go#4712 with some additional bug fixes and a couple missing features.

Protocol/Contract/API changes

• Removed protocolVersion from initialize params and response: protocol changes will be handled with LSP-like capabilities rather than specifying a version.
• Diagnostic code is now required.
• Removed the restriction on overlapping original-text spans. (cc Remco Haszing (@remcohaszing) Lyu, Wei-Da (@jasonlyu123))
• The VS Code API registration takes an inferredProjectContribution property, not an inferredProject property. (Previously shipped with an incomplete rename.)
• Previously, when go-to-definition or references returned a result in virtual text with no mapping, a fake result at the top of the file was returned as a fallback. This was done so default exports representing components/templates could be synthesized with no mapping, but going to the definition of an imported component was guaranteed to navigate the user to the file. However, this breaks the ability for the content mapper to opt out of those LSP features, and in the case where a 3rd party extension might provide a better implementation, the stub result from TypeScript would still be returned. I decided it’s better not to synthesize this fallback, because it can be done by the mapper. If your content mapper synthesizes any module exports, ensure those exports at least have a mapping to a zero-length range at the top of the file with SpanMapFeature.Definition.

Features

• Declaration maps are now emitted (fixes feat(contentmapper): emit declaration maps for mapped inputs #63880).
• Hover now concatenates results from multiple projections.

Bug fixes

Several, see individual commits.

[Copilot]

Pull request overview

Completes the second content-mapper integration round across compiler emit, span mapping, language services, protocol handling, and VS Code registration.

Changes:

• Emits declaration maps composed through content-mapper mappings.
• Adds multi-projection support for hover, formatting, folding, CodeLens, signature help, and navigation.
• Updates mapper contracts, extension matching, diagnostics, build watching, tests, and baselines.

Reviewed changes

Copilot reviewed 80 out of 83 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
tsc/testdata/tests/cases/compiler/contentMapperDeclarationEmitFailure.ts	Tests declaration emit after mapper failure.
tsc/testdata/tests/cases/compiler/contentMapperDeclarationEmit.ts	Expands mapped declaration-map coverage.
tsc/testdata/baselines/reference/fourslash/vsFindAllReferences/contentMapperDisabledNavigationTargets.baseline	Baselines disabled VS references.
tsc/testdata/baselines/reference/fourslash/state/codeLensAcrossProjects.baseline	Records CodeLens virtual positions.
tsc/testdata/baselines/reference/fourslash/quickInfo/contentMapperHoverConcatenatesProjections.baseline	Baselines combined hover output.
tsc/testdata/baselines/reference/fourslash/goToDefinition/contentMapperDisabledNavigationTargets.baseline.jsonc	Baselines disabled definitions.
tsc/testdata/baselines/reference/fourslash/goToDefinition/contentMapperDeclarationMapNavigation.baseline.jsonc	Baselines declaration-map definitions.
tsc/testdata/baselines/reference/fourslash/findAllReferences/contentMapperDisabledNavigationTargets.baseline.jsonc	Baselines disabled references.
tsc/testdata/baselines/reference/fourslash/findAllReferences/contentMapperDeclarationMapNavigation.baseline.jsonc	Baselines mapped references.
tsc/testdata/baselines/reference/fourslash/codeLenses/contentMapperSupplementalImplementationCodeLens.baseline.jsonc	Baselines supplemental implementation lenses.
tsc/testdata/baselines/reference/fourslash/codeLenses/contentMapperSupplementalCodeLens.baseline.jsonc	Baselines supplemental reference lenses.
tsc/testdata/baselines/reference/fourslash/codeLenses/contentMapperDisabledSupplementalCodeLens.baseline.jsonc	Baselines disabled supplemental lenses.
tsc/testdata/baselines/reference/fourslash/codeLenses/contentMapperDeduplicatesProjectedCodeLens.baseline.jsonc	Baselines deduplicated lenses.
tsc/testdata/baselines/reference/compiler/contentMapperSupplementalModule.errors.txt	Uses original filenames in diagnostics.
tsc/testdata/baselines/reference/compiler/contentMapperSupplementalDiagnostics.errors.txt	Updates supplemental diagnostic filenames.
tsc/testdata/baselines/reference/compiler/contentMapperDeclarationEmitFailure.types	Adds failed-map type baseline.
tsc/testdata/baselines/reference/compiler/contentMapperDeclarationEmitFailure.symbols	Adds failed-map symbol baseline.
tsc/testdata/baselines/reference/compiler/contentMapperDeclarationEmitFailure.sourcemap.txt	Adds empty declaration-map record.
tsc/testdata/baselines/reference/compiler/contentMapperDeclarationEmitFailure.js.map	Adds failed-map output.
tsc/testdata/baselines/reference/compiler/contentMapperDeclarationEmitFailure.js	Adds failed declaration output.
tsc/testdata/baselines/reference/compiler/contentMapperDeclarationEmitFailure.contentmapper	Baselines mapper failure details.
tsc/testdata/baselines/reference/compiler/contentMapperDeclarationEmit.types	Updates declaration types.
tsc/testdata/baselines/reference/compiler/contentMapperDeclarationEmit.symbols	Updates declaration symbols.
tsc/testdata/baselines/reference/compiler/contentMapperDeclarationEmit.sourcemap.txt	Baselines composed mappings.
tsc/testdata/baselines/reference/compiler/contentMapperDeclarationEmit.js.map	Adds mapped declaration source map.
tsc/testdata/baselines/reference/compiler/contentMapperDeclarationEmit.js	Updates declaration output.
tsc/testdata/baselines/reference/compiler/contentMapperDeclarationEmit.contentmapper	Updates transformed-content baseline.
tsc/internal/tsoptions/tsconfigparsing.go	Canonicalizes mapper extensions.
tsc/internal/tsoptions/tsconfigparsing_test.go	Tests extension casing rules.
tsc/internal/testutil/tsbaseline/sourcemap_baseline.go	Supports mapped declaration-map baselines.
tsc/internal/testutil/tsbaseline/error_baseline.go	Counts renamed supplemental diagnostics.
tsc/internal/testutil/harnessutil/harnessutil.go	Uses original text for map records.
tsc/internal/testutil/contentmappertest/protocol.go	Removes protocol-version fixtures.
tsc/internal/testutil/contentmappertest/editing.go	Adds supplemental feature fixtures.
tsc/internal/testutil/contentmappertest/duplicate.go	Adds hover/signature projections.
tsc/internal/testutil/contentmappertest/component.go	Anchors synthesized default exports.
tsc/internal/spanmap/spanmap.go	Supports overlaps and exact position mapping.
tsc/internal/spanmap/spanmap_test.go	Tests overlap and endpoint behavior.
tsc/internal/sourcemap/generator.go	Handles generated-only mapping precedence.
tsc/internal/sourcemap/generator_test.go	Tests same-position mapping precedence.
tsc/internal/printer/printer.go	Adds source-position composition hook.
tsc/internal/outputpaths/outputpaths.go	Allocates mapped declaration maps.
tsc/internal/lsp/server.go	Makes contributed extensions case-insensitive.
tsc/internal/lsp/server_contentmapper_internal_test.go	Tests contribution extension casing.
tsc/internal/lsp/lsproto/lsp_generated.go	Adds CodeLens projection metadata.
tsc/internal/lsp/lsproto/_generate/generate.mts	Generates new CodeLens fields.
tsc/internal/ls/signaturehelp.go	Tries multiple signature projections.
tsc/internal/ls/rename.go	Adapts cross-project invocation.
tsc/internal/ls/lsconv/converters.go	Converts original-document ranges.
tsc/internal/ls/hover.go	Combines hover projections.
tsc/internal/ls/format.go	Formats mapped verbatim ranges.
tsc/internal/ls/folding.go	Aggregates mapped folding ranges.
tsc/internal/ls/findallreferences.go	Applies feature-aware navigation mapping.
tsc/internal/ls/definition.go	Removes synthetic navigation fallbacks.
tsc/internal/ls/crossproject.go	Accepts precomputed symbol data.
tsc/internal/ls/codelens.go	Supports supplemental CodeLens resolution.
tsc/internal/ls/callhierarchy.go	Adapts cross-project invocation.
tsc/internal/ls/autoimport/registry.go	Excludes supplemental auto-import targets.
tsc/internal/fourslash/tests/contentMapperSignatureHelp_test.go	Tests signature projection fallback.
tsc/internal/fourslash/tests/contentMapperHover_test.go	Tests hover fallback and concatenation.
tsc/internal/fourslash/tests/contentMapperEditSafety_test.go	Tests folding, CodeLens, and formatting.
tsc/internal/fourslash/tests/contentMapperDuplicateMappings_test.go	Tests disabled navigation targets.
tsc/internal/fourslash/tests/contentMapperDeclarationMapNavigation_test.go	Tests declaration-map navigation.
tsc/internal/fourslash/tests/contentMapperAutoImports_test.go	Tests supplemental auto-import exclusion.
tsc/internal/execute/tsctests/contentmapper_watch_test.go	Tests diagnostics, collisions, and symlink watching.
tsc/internal/execute/build/orchestrator.go	Resolves watched mapper manifests.
tsc/internal/execute/build/buildtask.go	Detects physical supplemental-file conflicts.
tsc/internal/diagnosticwriter/diagnosticwriter.go	Presents canonical supplemental filenames.
tsc/internal/diagnostics/extraDiagnosticMessages.json	Removes obsolete diagnostics.
tsc/internal/diagnostics/diagnostics_generated.go	Regenerates diagnostic definitions.
tsc/internal/contentmapper/hostimpl.go	Revises mapper protocol contracts.
tsc/internal/contentmapper/host.go	Removes protocol-version errors.
tsc/internal/contentmapper/host_test.go	Updates host protocol tests.
tsc/internal/compiler/fileloader.go	Removes obsolete mapper diagnostics.
tsc/internal/compiler/emitter.go	Composes declaration source maps.
packages/vscode-typescript/test/tsconfig.json	Configures extension tests.
packages/vscode-typescript/test/index.test.ts	Aggregates extension tests.
packages/vscode-typescript/test/contentMapperContributions.test.ts	Tests contribution serialization and matching.
packages/vscode-typescript/src/contentMapperContributions.ts	Completes API rename and casing support.
packages/vscode-typescript/package.json	Builds and runs aggregated tests.
packages/typescript/test/spanMap.test.ts	Tests public span-map overlap behavior.
packages/typescript/src/ast/spanMap.ts	Mirrors overlapping span-map support.
.github/skills/compiler-and-fourslash-tests/SKILL.md	Documents content-mapper test expectations.

Files not reviewed (1)

• tsc/internal/diagnostics/diagnostics_generated.go: Generated file

Suppressed comments (1)

tsc/internal/contentmapper/hostimpl.go:213

• This also does not make diagnostics[].code required when decoding: a mapper can omit it and the Go JSON decoder supplies 0, which is then emitted as the diagnostic code. Please validate field presence during response decoding rather than relying on the serialization tag.

	Code   int32 `json:"code"`

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[Andrew Branch (andrewbranch)]

Maybe controversial, but this was intentional. It didn't seem worth erroring over a missing code, but coalescing to 0 means it's visible when diagnostics are reported, so appears obvious as a mapper misconfiguration. It's more work and more code to validate and return a diagnostic.

[Jake Bailey (jakebailey)]

I assume this is now fine because fswatch handles this?

[Andrew Branch (andrewbranch)]

Ah, this was explained by #63936 (comment) — mapper.PackageDirectory is already a realpath.