Fix transform-case actions changing strings and comments

[maruthang]

Summary

Adds a new opt-in editor setting editor.transformCase.skipStringsAndComments (boolean, default false). When enabled, the case-transformation actions — Transform to Uppercase, Lowercase, Title Case, Snake Case, Camel Case, Pascal Case, Kebab Case — leave ranges classified as strings or comments by the active language's tokenizer untouched.

Default behavior is preserved: with the setting off, the actions take the original code path and produce byte-identical output to before.

Fixes #149616

Implementation

• New structured editor option editor.transformCase in src/vs/editor/common/config/editorOptions.ts, mirroring the editor.comments.* group so future sub-keys can be added without churn.
• Skip logic lives in AbstractCaseAction.run() in src/vs/editor/contrib/linesOperations/browser/linesOperations.ts. Two helpers:
  • isRangeInStringOrComment — used when the user invokes the action with an empty selection (cursor in a word). Returns true only when every covered token is StandardTokenType.String or StandardTokenType.Comment.
  • splitRangeAroundStringsAndComments — used for non-empty selections. Walks the line tokens and emits a list of "code" sub-ranges that exclude any string/comment spans. Each surviving sub-range is transformed independently via the existing _modifyText(text, wordSeparators) hook, which means every concrete action — Upper/Lower/Title/Snake/Camel/Pascal/Kebab — inherits the new behavior without per-action plumbing.
• Uses model.tokenization.forceTokenization + findTokenIndexAtOffset, the same pattern as TrimTrailingWhitespaceCommand.

Test plan

• 9 new unit tests in linesOperations.test.ts covering:
  • Default-off behavior is unchanged (string is upper-cased).
  • Uppercase / Lowercase / Title Case all preserve string literals when the setting is on.
  • Line comments are preserved.
  • Multiple strings on a single line are all preserved.
  • Cursor inside a string with empty selection is left untouched.
  • Cursor inside an identifier with empty selection is still transformed.
  • Multi-line selection preserves strings on each line.
• Manual: open a JS/TS file with strings and comments, set "editor.transformCase.skipStringsAndComments": true, select code, run "Transform to Uppercase" — strings and comments untouched.

The custom mocha tests use a tiny tokenizer ('…' = string, //…EOL = comment) so the test is focused on the skip behavior rather than language plumbing.

[Copilot]

Pull request overview

Adds an opt-in editor setting to make case-transformation actions skip tokens classified as strings/comments by the active tokenizer, preserving existing behavior when disabled.

Changes:

• Introduces editor.transformCase.skipStringsAndComments (default false) via a new structured editor option group.
• Updates AbstractCaseAction.run() to split selections around string/comment token spans (and no-op when the cursor word is inside them).
• Adds unit tests with a lightweight tokenizer to validate skip behavior for strings/comments.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/vs/editor/common/config/editorOptions.ts	Registers the new structured transformCase editor option and setting key.
src/vs/editor/contrib/linesOperations/browser/linesOperations.ts	Implements skip logic for transform-case actions based on tokenizer StandardTokenType.
src/vs/editor/contrib/linesOperations/test/browser/linesOperations.test.ts	Adds unit tests (with a custom tokenizer) covering skip behavior and default behavior.

[Copilot]

withTokenizedTestEditor disposes the DisposableStore only after withTestCodeEditor returns. If an assertion in callback throws, disposables.dispose() will be skipped, which can leak the language/tokenization registrations and make subsequent tests flaky. Wrap the withTestCodeEditor/callback invocation in a try/finally and dispose in the finally block.

Suggested change

	withTestCodeEditor(model, { transformCase: { skipStringsAndComments: options.skipStringsAndComments } }, (editor) => {
	callback(editor, model);
	});
	disposables.dispose();
	try {
	withTestCodeEditor(model, { transformCase: { skipStringsAndComments: options.skipStringsAndComments } }, editor => {
	callback(editor, model);
	});
	} finally {
	disposables.dispose();
	}

[Copilot]

When skipStringsAndComments is enabled, it's possible for a selection/word to be entirely inside a string/comment, resulting in textEdits staying empty (e.g. due to the continue/no codeRanges). The action currently still calls pushUndoStop()/executeEdits() which can introduce undo stack elements even though no text changed. Consider early-returning when textEdits.length === 0 (before pushing undo stops) to avoid no-op undo stops.