Port parseCommandLine, readConfigFile, and parseJsonConfigFileContent

[John Favret (johnfav03)]

In the TS API, these are exposed as:

• parseCommandLine(commandLine: readonly string[], readFile?: (path: string) => string | undefined)
• readConfigFile(fileName: string, readFile: (path: string) => string | undefined)
• parseJsonConfigFileContent(json: any, host: ParseConfigHost, basePath: string, existingOptions?: CompilerOptions, configFileName?: string, resolutionStack?: Path[], extraFileExtensions?: readonly FileExtensionInfo[], extendedConfigCache?: Map<string, ExtendedConfigCacheEntry>, existingWatchOptions?: WatchOptions)

Part of #4830

[Copilot]

Pull request overview

Ports command-line and JSON config parsing APIs for the native-preview API, advancing #4830.

Changes:

• Adds parseCommandLine, readConfigFile, and parseJsonConfigFileContent.
• Adds watch-option, raw-config, and diagnostic serialization.
• Expands Go and TypeScript API coverage.

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
testdata/baselines/reference/tsc/showConfig/Show-TSConfig-with-compileOnSave-and-more.js	Updates compileOnSave baseline.
internal/tsoptions/tsconfigparsing.go	Parses and merges watch options and JSON values.
internal/tsoptions/tsconfigparsing_test.go	Tests JSON representations and watch options.
internal/tsoptions/declswatch.go	Exposes the watch-option map.
internal/tsoptions/commandlineparser.go	Adds API-compatible parsing and response-file safeguards.
internal/tsoptions/commandlineparser_test.go	Tests response-file parsing.
internal/api/session.go	Handles the new API requests.
internal/api/proto.go	Defines request and response protocol structures.
internal/api/proto_test.go	Tests ordered JSON decoding.
_packages/native-preview/test/sync/api.test.ts	Adds synchronous API integration tests.
_packages/native-preview/test/async/api.test.ts	Adds asynchronous API integration tests.
_packages/native-preview/src/api/sync/types.ts	Updates generated synchronous types.
_packages/native-preview/src/api/sync/api.ts	Exposes synchronous parsing APIs.
_packages/native-preview/src/api/proto.ts	Defines client protocol result types.
_packages/native-preview/src/api/async/types.ts	Shares diagnostic protocol types.
_packages/native-preview/src/api/async/api.ts	Exposes asynchronous parsing APIs.

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[Copilot]

Pull request overview

Copilot reviewed 16 out of 16 changed files in this pull request and generated 1 comment.

Suppressed comments (1)

internal/tsoptions/tsconfigparsing.go:1526

• This leaves CompileOnSave nil when the property is absent or invalid, so the API omits compileOnSave and clients observe undefined. The reference parseJsonConfigFileContent always returns a boolean using !!raw.compileOnSave (commandLineParser.ts:3106), which is false in these cases. Initialize the result to false and always return its pointer from config parsing.

	var compileOnSave *bool
	if raw, ok := parsedConfig.raw.(*collections.OrderedMap[string, any]); ok {
		if value, ok := raw.GetOrZero("compileOnSave").(bool); ok {
			compileOnSave = &value
		}

[Copilot]

Pull request overview

Copilot reviewed 17 out of 17 changed files in this pull request and generated 1 comment.

Suppressed comments (1)

internal/tsoptions/tsconfigparsing.go:1531

• The reference parseJsonConfigFileContent always returns a boolean compileOnSave (!!raw.compileOnSave), including false when the property is absent or invalid. Leaving this pointer nil causes the IPC response to omit the field, so callers receive undefined instead of the expected false. Initialize the result to false and overwrite it when a boolean value is present.

	var compileOnSave *bool
	if raw, ok := parsedConfig.raw.(*collections.OrderedMap[string, any]); ok {
		if value, ok := raw.GetOrZero("compileOnSave").(bool); ok {
			compileOnSave = &value
		}

[Andrew Branch (andrewbranch)]

This is looking very good!

[Andrew Branch (andrewbranch)]

Nice! Looks like this caught several config parsing bugs along the way. Thank you!

[Copilot]

Pull request overview

Copilot reviewed 18 out of 18 changed files in this pull request and generated 1 comment.

Suppressed comments (1)

internal/tsoptions/tsconfigparsing.go:980

• parseJsonConfigFileContent is expected to normalize raw.compileOnSave to a boolean even when the property is absent or invalid. The reference implementation always assigns convertCompileOnSaveOptionFromJson(...), whose default/error result is false (_submodules/TypeScript/src/compiler/commandLineParser.ts:3507-3514,3725-3730). This conditional leaves the key absent, or stores nil after a type error, and also lets an omitted value inherit true from an extended JSON config when the reference JSON API does not. Always write the normalized boolean default.

	if compileOnSave, ok := json.Get("compileOnSave"); ok {
		converted, compileOnSaveErrors := convertJsonOption(compileOnSaveCommandLineOption, compileOnSave, basePath, nil, nil, nil)
		errors = append(errors, compileOnSaveErrors...)
		json.Set("compileOnSave", converted)