Implement LSP-based code edits with file renaming by Andarist · Pull Request #3358 · microsoft/typescript-go

Andarist · 2026-04-07T06:58:39Z

Fixes #2244 and fuzzer crash from #3187 (comment).

The core implementation in file_rename.go is mostly a translation from the Strada code, except I deleted some code that seemed to be trying to do the same thing in 3 different ways (resolve a module specifier).
Notable changes include making file rename work when you rename a specifier for an arbitrary extension; see tests with names ending in cssImport.
I also removed Strada's source map supporting code because it didn't seem to work for file renames, only for directory renames, so I thought we might as well declare that scenario as out of scope (one shouldn't be renaming an output directory or output files...).

The overall flow is also new because of how LSP works: the server subscribes to receive willRenameFiles requests from the client for supported extensions. Then, if the user renames a file directly, the server will compute any additional edits and renames needed. If a user invokes regular rename on a module specifier, the server will reply with a file rename document change, and then the client should send a willRenameFiles request, and the server computes edits.

I decided to not support a bunch of cases:

Renames that would require following source maps to figure out what original files to rename
Renames of files with arbitrary extensions, even if they have a corresponding declaration file: I could either make it so we rename e.g. app.css upon a rename of app.d.css, or the other way around, because supporting both leads to a cycle of willRenameFiles. I decided for the latter, because it naturally supports the scenario where the rename is initiated from renaming an import specifier (which resolves to a declaration file and is the thing we ask the client to rename).
If a file being renamed moves to a different program, then it's possible we'll incorrectly update its module specifiers or not respect package.json
If the client does not support document changes or file rename in document changes, we (1) don't allow rename of module specifier, but still support file renames via willRenameFiles and only return changes.

gabritto · 2026-04-10T22:08:29Z

internal/fourslash/_scripts/manualTests.txt

 exhaustiveCaseCompletions7
 exhaustiveCaseCompletions8
 formatOnEnterInComment
+getEditsForFileRename_caseInsensitive


Some tests are manual because we needed to specify case insensitivity, but most are because I changed fourslash such that the expected file content map uses file names after the rename.

gabritto · 2026-04-10T22:22:19Z

internal/ls/file_rename.go

+
+	if target == nil {
+		// First fall back: try every file in the program to see if any of them would match the import specifier, and if so, obtain the updated specifier for that file.
+		if updated := getUpdatedImportSpecifierFromMovedSourceFiles(program, sourceFile, importLiteral, oldToNew, newImportFromPath, userPreferences); updated != "" && updated != importLiteral.Text() {


This allows us to properly rename in some cases where there's a module resolution error and the import doesn't resolve to a renamed file because of the error. It's kinda inefficient though, so maybe we should just say if you have resolution errors, it's too bad, but I left it for now.

gabritto · 2026-04-10T22:24:18Z

internal/ls/rename.go

 	}, true
 }

+func (l *LanguageService) getNewFileNameForModuleRename(oldPath, specifierText, newName string) string {


This used to be done in the built-in extension.

gabritto · 2026-04-10T22:52:53Z

internal/outputpaths/outputpaths.go

 	return ""
 }

-func getDeclarationEmitExtensionForPath(fileName string) string {


This was duplicated.

gabritto · 2026-04-10T22:55:00Z

...ourslash/state/declarationMapsRenameWithDisableSourceOfProjectReferenceRedirectEdit.baseline

  }
 }

+//// [/myproject/dependency/FnS.ts] *modified* 


These baselines changed basically because I made fourslash's editScript also update its vfs, to avoid inconsistencies between the vfs and fourslash's script infos.

Copilot

Pull request overview

This PR adds LSP-driven support for updating imports/configs during file (and directory) renames, including returning RenameFile document changes for module-specifier renames and computing additional workspace edits via workspace/willRenameFiles. It also extends declaration-extension handling to support arbitrary extensions (e.g. .d.css.ts) and expands fourslash tooling/tests to cover the new behavior.

Changes:

Implement workspace/willRenameFiles handling and integrate rename of module specifiers with file renames + follow-up edits.
Add LanguageService.GetEditsForFileRename to compute import/reference/tsconfig updates (plus companion renames like .d.css.ts -> .css).
Update fourslash harness + converter tooling and add/convert tests for file-rename edit computation.

Reviewed changes

Copilot reviewed 64 out of 64 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
testdata/baselines/reference/fourslash/state/findAllRefsDoesNotTryToSearchProjectAfterItsUpdateDoesNotIncludeTheFile.baseline	Baseline update reflecting modified-file tracking.
testdata/baselines/reference/fourslash/state/declarationMapsRenameWithSourceMapsNotSolutionEditEnd.baseline	Baseline update for rename state output.
testdata/baselines/reference/fourslash/state/declarationMapsRenameWithSourceMapsNotSolutionEdit.baseline	Baseline update for rename state output.
testdata/baselines/reference/fourslash/state/declarationMapsRenameWithSourceMapsEditEnd.baseline	Baseline update for rename state output.
testdata/baselines/reference/fourslash/state/declarationMapsRenameWithSourceMapsEdit.baseline	Baseline update for rename state output.
testdata/baselines/reference/fourslash/state/declarationMapsRenameWithProjectReferencesEditEnd.baseline	Baseline update for rename state output.
testdata/baselines/reference/fourslash/state/declarationMapsRenameWithProjectReferencesEdit.baseline	Baseline update for rename state output.
testdata/baselines/reference/fourslash/state/declarationMapsRenameWithDisableSourceOfProjectReferenceRedirectEditEnd.baseline	Baseline update for rename state output.
testdata/baselines/reference/fourslash/state/declarationMapsRenameWithDisableSourceOfProjectReferenceRedirectEdit.baseline	Baseline update for rename state output.
internal/tspath/extension.go	Generalize `.d.*.ts` handling and declaration emit extension selection for arbitrary extensions.
internal/testutil/harnessutil/harnessutil.go	Export/expand test-config option parsing (with optional unknown-option allowance).
internal/project/snapshot.go	Expose `Snapshot.FileExists` for LS features needing snapshot FS existence checks.
internal/project/session.go	Add helper to construct language services for rename processing.
internal/outputpaths/outputpaths.go	Centralize declaration emit extension logic via `tspath`.
internal/modulespecifiers/specifiers.go	Introduce `UpdateModuleSpecifier` that accepts user preferences (for rename updates).
internal/lsp/server.go	Register/handle `workspace/willRenameFiles` and route `textDocument/rename` via server to support file renames.
internal/ls/rename.go	Extend rename info to include file rename intent; add client capability helpers; compute correct target file for specifier rename.
internal/ls/host.go	Add `FileExists` to LS host interface for rename companion file checks.
internal/ls/file_rename.go	New core implementation computing edits (imports/refs/tsconfig) and related file renames for file/directory rename.
internal/ls/crossproject.go	Combine rename responses including `DocumentChanges` (not just `Changes`).
internal/ls/codeactions_importfixes.go	Dedupe identical auto-import fix suggestions.
internal/ls/autoimport/specifiers.go	Adjust module specifier generation for symlinked package exports (realpath handling).
internal/fourslash/tests/renameImportSpecifierNoResourceOperations_test.go	New test ensuring rename fails when resource operations aren’t supported.
internal/fourslash/tests/manual/getEditsForFileRename_unaffectedNonRelativePath_test.go	Manual test for non-relative path stability under rename.
internal/fourslash/tests/manual/getEditsForFileRename_subDir_test.go	Manual test for moving file into subdir updates relative imports.
internal/fourslash/tests/manual/getEditsForFileRename_shortenRelativePaths_test.go	Manual test for shortening relative paths after rename.
internal/fourslash/tests/manual/getEditsForFileRename_resolveJsonModule_test.go	Manual test for JSON module import updates under rename.
internal/fourslash/tests/manual/getEditsForFileRename_preservePathEnding_test.go	Manual test preserving specifier endings like `.`, `./index`, explicit extensions.
internal/fourslash/tests/manual/getEditsForFileRename_preferences_test.go	Manual test honoring module specifier + quote preferences.
internal/fourslash/tests/manual/getEditsForFileRename_jsExtension_test.go	Manual test for `.js` extension preservation/updates.
internal/fourslash/tests/manual/getEditsForFileRename_directory_up_test.go	Manual test for directory rename moving up the tree.
internal/fourslash/tests/manual/getEditsForFileRename_directory_down_test.go	Manual test for directory rename moving down the tree.
internal/fourslash/tests/manual/getEditsForFileRename_caseInsensitive_test.go	Manual test for case-insensitive FS behavior.
internal/fourslash/tests/getEditsForFileRename_jsRename_test.go	New rename test covering `.js`-style specifier rename -> file rename.
internal/fourslash/tests/getEditsForFileRename_cssImport4_test.go	New test intended to cover fallback behavior when file operations aren’t supported.
internal/fourslash/tests/getEditsForFileRename_cssImport3_test.go	New test for css import specifier rename behavior.
internal/fourslash/tests/getEditsForFileRename_cssImport2_test.go	New test for willRenameFiles edits when renaming `.d.css.ts`.
internal/fourslash/tests/gen/getEditsForFileRename_unresolvableNodeModule_test.go	Converted/generated coverage for rename edits.
internal/fourslash/tests/gen/getEditsForFileRename_unresolvableImport_test.go	Converted/generated coverage for rename edits.
internal/fourslash/tests/gen/getEditsForFileRename_tsconfig_test.go	Converted/generated coverage for tsconfig path updates.
internal/fourslash/tests/gen/getEditsForFileRename_tsconfig_include_noChange_test.go	Converted/generated coverage for include behavior.
internal/fourslash/tests/gen/getEditsForFileRename_tsconfig_include_add_test.go	Converted/generated coverage for include insertion behavior.
internal/fourslash/tests/gen/getEditsForFileRename_tsconfig_empty_include_test.go	Converted/generated coverage for empty include behavior.
internal/fourslash/tests/gen/getEditsForFileRename_test.go	Converted/generated base coverage for file rename edits.
internal/fourslash/tests/gen/getEditsForFileRename_symlink_test.go	Converted/generated coverage for symlink scenarios.
internal/fourslash/tests/gen/getEditsForFileRename_renameToIndex_test.go	Converted/generated coverage for renaming to `index`.
internal/fourslash/tests/gen/getEditsForFileRename_renameFromIndex_test.go	Converted/generated coverage for renaming from `index`.
internal/fourslash/tests/gen/getEditsForFileRename_notAffectedByJsFile_test.go	Converted/generated coverage for TS-vs-JS sibling file behavior.
internal/fourslash/tests/gen/getEditsForFileRename_nodeModuleDirectoryCase_test.go	Converted/generated coverage for node_modules dir casing rename.
internal/fourslash/tests/gen/getEditsForFileRename_keepFileExtensions_test.go	Converted/generated coverage for keeping `.js` in specifiers under Node16/Next modes.
internal/fourslash/tests/gen/getEditsForFileRename_js_simple_test.go	Converted/generated coverage for basic JS rename edits.
internal/fourslash/tests/gen/getEditsForFileRename_directory_test.go	Converted/generated coverage for directory rename edits.
internal/fourslash/tests/gen/getEditsForFileRename_directory_noUpdateNodeModulesImport_test.go	Converted/generated coverage ensuring node module imports aren’t rewritten.
internal/fourslash/tests/gen/getEditsForFileRename_casing_test.go	Converted/generated coverage for preserving path casing.
internal/fourslash/tests/gen/getEditsForFileRename_amd_test.go	Converted/generated coverage for classic/AMD-ish resolution scenario.
internal/fourslash/tests/gen/getEditsForFileRename_ambientModule_test.go	Converted/generated coverage ensuring ambient modules unaffected.
internal/fourslash/test_parser.go	Allow certain global directives alongside config files (e.g. symlink/useCaseSensitiveFileNames).
internal/fourslash/fourslash.go	Major harness updates: apply multi-edits safely, emulate rename + willRenameFiles flows, default capabilities updates.
internal/fourslash/_scripts/unparsedTests.txt	Remove now-supported getEditsForFileRename entries from “unparsed”.
internal/fourslash/_scripts/manualTests.txt	Add manual test names for conversion workflow.
internal/fourslash/_scripts/failingTests.txt	Update failing-test list after symlink handling changes.
internal/fourslash/_scripts/convertFourslash.mts	Add conversion support for `verify.getEditsForFileRename`.
internal/diagnostics/extraDiagnosticMessages.json	Add new editor-capability error message for file rename.
internal/diagnostics/diagnostics_generated.go	Regenerate diagnostics to include new message code.

Copilot · 2026-04-10T23:41:26Z

internal/ls/file_rename.go

+	if tspath.IsDeclarationFileName(oldPath) && tspath.IsDeclarationFileName(newPath) {
+		dtsExt := tspath.GetDeclarationFileExtension(oldPath)
+		originalExtensions := tspath.GetPossibleOriginalInputExtensionForExtension(dtsExt)
+		for _, ext := range originalExtensions {
+			oldOriginalPath := tspath.ChangeFullExtension(oldPath, ext)
+			if l.host.FileExists(oldOriginalPath) {
+				newDtsExt := tspath.GetDeclarationFileExtension(oldPath)
+				newOriginalExtensions := tspath.GetPossibleOriginalInputExtensionForExtension(newDtsExt)
+				if slices.Contains(newOriginalExtensions, ext) {
+					newOriginalPath := tspath.ChangeFullExtension(newPath, ext)


In the declaration-file rename companion logic, newDtsExt is derived from oldPath instead of newPath. This breaks the check when the declaration extension changes during rename (e.g. .d.css.ts -> .d.scss.ts), and can incorrectly skip/allow renaming the original file. Use tspath.GetDeclarationFileExtension(newPath) (and consider computing both old/new once outside the loop).

Copilot · 2026-04-10T23:41:26Z

internal/project/session.go

+func (s *Session) GetLanguageServicesForDocuments(ctx context.Context, uris []lsproto.DocumentUri) []*ls.LanguageService {
+	snapshot := s.getSnapshot(
+		ctx,
+		ResourceRequest{Documents: uris},
+		false, /*callerRef*/
+	)
+
+	activeFile := ""
+	if len(uris) > 0 {
+		activeFile = uris[0].FileName()
+	}
+
+	projects := snapshot.ProjectCollection.Projects()
+	services := make([]*ls.LanguageService, 0, len(projects))
+	for _, project := range projects {
+		services = append(services, ls.NewLanguageService(project.configFilePath, project.GetProgram(), snapshot, activeFile))
+	}
+	return services


GetLanguageServicesForDocuments currently creates a LanguageService for every project in the snapshot, even if none of the uris belong to most projects. In large workspaces this makes willRenameFiles scale with total project count. Consider filtering to only projects that contain any of the provided documents (e.g. via snapshot.GetProjectsContainingFile per URI, then dedupe) before constructing services.

This sounds plausible but doesn't work, because we need to visit all projects that can depend on the project that contains the file.

internal/fourslash/fourslash.go

internal/fourslash/tests/getEditsForFileRename_cssImport4_test.go

internal/fourslash/tests/getEditsForFileRename_jsRename_test.go

Andarist added 7 commits April 6, 2026 23:40

Implement LSP-based code edits with file renaming

99d980d

better gate

c9b386d

add test

661d707

add tests

d10a512

Merge remote-tracking branch 'origin/main' into will-rename-files

a4802d4

fmt

0f8d4b5

lint

7615f8a

Andarist force-pushed the will-rename-files branch from 6810db7 to 7615f8a Compare April 7, 2026 09:17

Andarist added 4 commits April 7, 2026 11:36

updatefailing

ba00123

dont specialcse baseUrl, just make those test manual

3af10f8

make another test manual

a2723ad

normalize line endings

350f3bc

gabritto self-assigned this Apr 7, 2026

Gabriela Araujo Britto added 7 commits April 7, 2026 19:10

WIP: refactor

40acfe8

Merge branch 'main' into will-rename-files

0cbcd1a

refactor fourslash

983aece

refactor; delete unused code

334a32b

fix arbitrary extension case and tests + refactorings

324aa20

make rename of resolving to .d.ts work

252eb61

remove support for arbitrary files; respect client capabilities

d4fdbca

gabritto reviewed Apr 10, 2026

View reviewed changes

Gabriela Araujo Britto added 2 commits April 10, 2026 22:56

fix handling of client capabilities, cleanup

4ea519c

Merge branch 'main' into will-rename-files

4ccf8b1

gabritto marked this pull request as ready for review April 10, 2026 23:32

Copilot AI review requested due to automatic review settings April 10, 2026 23:32

Copilot started reviewing on behalf of gabritto April 10, 2026 23:34 View session

Copilot AI reviewed Apr 10, 2026

View reviewed changes

Gabriela Araujo Britto added 2 commits April 10, 2026 23:43

add test from fuzzer crash

971d708

feedback

16c0a43

gabritto requested a review from andrewbranch April 11, 2026 00:18

gabritto mentioned this pull request Apr 11, 2026

Fixes a crash when renaming import path of a JSON file #3196

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Implement LSP-based code edits with file renaming#3358

Implement LSP-based code edits with file renaming#3358
Andarist wants to merge 22 commits intomicrosoft:mainfrom
Andarist:will-rename-files

Andarist commented Apr 7, 2026 •

edited by gabritto

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edited

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Andarist commented Apr 7, 2026 •

edited by gabritto

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