Redo localization for onboarding

[Jake Bailey (jakebailey)]

This reorganizes our localization files to match what the loc team expects, which should allow us to start localization up again.

The gist is that we run a pipeline which sends them the diagnostics, then the same task pulls their current localizations, and the bot opens a PR if that's changed. (A previous version of this PR used their architecture which sends us PRs, but that would prevent us from compressing the diags, which is unfortuante.)

I've also added support so that we can also localize the VS Code extension strings, modeling other Microsoft extensions' repos. Removed that.

[Copilot]

🔵 Needs a closer look

The broad localization and diagnostic-catalog migration has unresolved compatibility, packaging, and runtime-delivery risks.

Pull request overview

Reworks compiler and VS Code localization to match the localization team’s expected workflow.

Changes:

• Replaces compressed locale assets with generated JSON files supporting embedded and noembed builds.
• Consolidates and renumbers diagnostic messages and updates affected tests.
• Adds localization configuration and packaging support for the VS Code extension.

File summaries

File	Description
tsc/testdata/baselines/reference/tsc/contentMapperFailures/transform-failure-reports-a-per-file-error.js	Updates the expected diagnostic code.
tsc/testdata/baselines/reference/tsc/contentMapperFailures/mapper-is-disabled-after-repeated-failures.js	Updates content-mapper diagnostic codes.
tsc/testdata/baselines/reference/tsc/contentMapperFailures/initialization-failure-reports-one-project-error.js	Updates the initialization diagnostic code.
tsc/testdata/baselines/reference/fourslash/syntaxandSemanticDiagnostics/contentMapperSynthesizedDiagnostics.baseline	Updates synthesized diagnostic codes.
tsc/testdata/baselines/reference/compiler/contentMapperSupplementalFileCollision.contentmapper	Updates the collision diagnostic code.
tsc/testdata/baselines/reference/compiler/contentMapperInvalidExtension.contentmapper	Updates the invalid-extension diagnostic code.
tsc/testdata/baselines/reference/compiler/contentMapperInvalidDiagnosticDirectives.contentmapper	Updates directive diagnostic codes.
tsc/testdata/baselines/reference/compiler/contentMapperDeclarationEmitFailure.contentmapper	Updates the emit-failure diagnostic code.
tsc/internal/fourslash/tests/contentMapperDiagnostics_test.go	Updates the expected LSP diagnostic code.
tsc/internal/execute/tsctests/contentmapper_watch_test.go	Updates the watch-test diagnostic assertion.
tsc/internal/diagnostics/localizations.go	Adds shared locale loading and fallback behavior.
tsc/internal/diagnostics/localizations_noembed.go	Loads external locale files for noembed builds.
tsc/internal/diagnostics/localizations_generated.go	Defines generated locale names, matching, and loaders.
tsc/internal/diagnostics/localizations_embed.go	Embeds generated locale JSON files.
tsc/internal/diagnostics/loc/README.md	Documents ownership of generated locale files.
tsc/internal/diagnostics/loc_generated.go	Removes compressed embedded localization code.
tsc/internal/diagnostics/generate.go	Reworks diagnostic and localization generation.
tsc/internal/diagnostics/generate_deps.go	Removes the obsolete compression dependency shim.
tsc/internal/diagnostics/extraDiagnosticMessages.json	Removes the separate extra diagnostic catalog.
tsc/internal/diagnostics/diagnostics.go	Uses generated locale loaders directly.
tsc/internal/diagnostics/diagnostics_test.go	Adds locale-file and placeholder validation.
tsc/internal/diagnostics/diagnostics_generated.go	Regenerates diagnostics with consolidated codes.
tsc/internal/diagnostics/diagnosticMessages.json	Consolidates messages into the primary catalog.
tsc/go.sum	Removes compression dependency checksums.
tsc/go.mod	Removes the compression dependency.
tools/LocProject.json	Configures compiler and extension localization handbacks.
packages/vscode-typescript/package.json	Includes localized extension resources.
Herebyfile.mjs	Copies runtime locale files during builds.
.dprint.jsonc	Excludes generated localization artifacts from formatting.

Review details

Files not reviewed (1)

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

• Files reviewed: 27/69 changed files
• Comments generated: 4
• Review effort level: Balanced

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[Jake Bailey (jakebailey)]

Classic copilot producing good feedback

[Copilot]

🟡 Changes recommended

The formatter exclusions omit generated nightly extension localization handbacks.

Get a fresh assessment by requesting another Copilot review.

Review details

Files not reviewed (1)

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

• Files reviewed: 28/70 changed files
• Comments generated: 1
• Review effort level: Balanced

[Copilot]

🟡 Changes recommended

Handback failures and stale generated outputs can still produce incomplete or outdated localization updates.

Get a fresh assessment by requesting another Copilot review.

Review details

Files not reviewed (1)

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

• Files reviewed: 22/50 changed files
• Comments generated: 2
• Review effort level: Balanced

[Copilot]

🟡 Changes recommended

The scheduled pipeline lacks the GitHub App variables required to create its update pull request.

Get a fresh assessment by requesting another Copilot review.

Review details

Files not reviewed (1)

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

• Files reviewed: 22/50 changed files
• Comments generated: 1
• Review effort level: Balanced

[Daniel Rosenwasser (DanielRosenwasser)]

I've also added support so that we can also localize the VS Code extension strings, modeling other Microsoft extensions' repos.

CC TylerLeonhardt

[Daniel Rosenwasser (DanielRosenwasser)]

Just to recap other convos we've had with Isabel Duan (@iisaduan) and Tyler, the plan was that will be ship as a built-in extension for VS Code, so I just want to make sure we're doing the right thing.

[Jake Bailey (jakebailey)]

Then we need to discuss this, as the standard thing to do is to submit our localization to the loc team, then we commit those files back, and those get published in the VSIX to the marketplace. If there needs to be some special build that doesn't have those locs and are placed elsewhere, then VS Code needs to perform surgery on out outputs when they bundle us or something.

[Jake Bailey (jakebailey)]

Per Tyler:

what you ship on the marketplace should include it's own localizations. Once we're ready to pull your extension in, then we can talk about getting the localizations in the vscode language packs

So, I think this PR is good to go

[Jake Bailey (jakebailey)]

Okay, I removed the vscode stuff, since that's still in the air.

[Copilot]

Copilot review overview

🟡 Changes recommended

The localization pipeline invokes hereby without first installing its required Node dependencies.

Get a fresh assessment by requesting another Copilot review.

Review effort: Balanced
Findings: 1

Open (1)

• Install Node dependencies before running go generate · New

Resolved since last review (1)

• This pipeline later invokes create-github-app-token.yml, which reads…

Files not reviewed (1)

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

[Copilot]

Copilot review overview

🟡 Changes recommended

The update pipeline skips artifact generation and would stage its temporary .npmrc.

Get a fresh assessment by requesting another Copilot review.

Review effort: Balanced
Findings: 1

Open (1)

• Prevent temporary .npmrc from being included in localization PRs · New

Resolved since last review (1)

• Install Node dependencies before running go generate

Files not reviewed (1)

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

Previously missed (1)

In code that hasn't changed since last review

Invoke the diagnostics generator to refresh localization outputs

tools/​pipelines/​localization-update.yml:121

This command is a no-op: -run filters //go:generate directives by their text, but the directive in tsc/internal/diagnostics/diagnostics.go:16 is npx hereby generate:diagnostics, which does not match generate.go. The job therefore applies handbacks without regenerating loc_generated.go or the gzip archives. Invoke the generator task directly.