Applying custom line heights after the edits are processed by aiday-mar · Pull Request #297999 · microsoft/vscode

aiday-mar · 2026-02-26T13:37:37Z

Copilot

Pull request overview

This PR changes how variable/custom line heights are applied during structural model edits (insert/delete), deferring custom line-height computation until after the view model has processed the full edit batch and projections/coordinate conversion are stable.

Changes:

Removed “lineHeightsAdded” plumbing from onLinesInserted across ViewLayout → LinesLayout → LineHeightsManager.
Deferred recomputation/application of custom line heights in ViewModel.onDidChangeContentOrInjectedText until after all raw changes are applied.
Extended ModelRawLinesDeleted to carry lastUntouchedLinePostEdit, and updated relevant tests.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/vs/editor/test/common/viewLayout/linesLayout.test.ts	Updates tests to match the new `onLinesInserted(from,to)` signature.
src/vs/editor/test/common/viewLayout/lineHeights.test.ts	Updates tests for new signature and adds a new deletion-related test (currently problematic).
src/vs/editor/test/common/model/model.test.ts	Updates expected `ModelRawLinesDeleted` constructor args.
src/vs/editor/common/viewModel/viewModelLines.ts	Adds debug `console.log` statements inside model line insertion handling.
src/vs/editor/common/viewModel/viewModelImpl.ts	Defers custom line height application until projections are stable after batch processing.
src/vs/editor/common/viewLayout/viewLayout.ts	Updates `onLinesInserted` API to drop the custom-line-height payload.
src/vs/editor/common/viewLayout/linesLayout.ts	Updates `onLinesInserted` and forwards to `LineHeightsManager` without payload.
src/vs/editor/common/viewLayout/lineHeights.ts	Removes inserted-line height payload handling; insertion now assumes default height until recomputed later.
src/vs/editor/common/textModelEvents.ts	Extends `ModelRawLinesDeleted` with `lastUntouchedLinePostEdit`.
src/vs/editor/common/model/tokens/tokenizationFontDecorationsProvider.ts	Adds debug `console.log` statements (including logging full buffer content).
src/vs/editor/common/model/textModel.ts	Computes and emits `lastUntouchedLinePostEdit` when generating `ModelRawLinesDeleted`.

src/vs/editor/common/textModelEvents.ts

Copilot · 2026-02-26T13:43:24Z

src/vs/editor/common/viewModel/viewModelImpl.ts

@@ -370,6 +375,7 @@ export class ViewModel extends Disposable implements IViewModel {
 						if (linesDeletedEvent !== null) {
 							eventsCollector.emitViewEvent(linesDeletedEvent);
 							this.viewLayout.onLinesDeleted(linesDeletedEvent.fromLineNumber, linesDeletedEvent.toLineNumber);
+							deferredCustomLineHeightRanges.push({ fromLineNumber: change.lastUntouchedLinePostEdit, toLineNumber: change.lastUntouchedLinePostEdit });
 						}
 						hadOtherModelChange = true;
 						break;
@@ -379,7 +385,8 @@ export class ViewModel extends Disposable implements IViewModel {
 						const linesInsertedEvent = this._lines.onModelLinesInserted(versionId, change.fromLineNumber, change.toLineNumber, insertedLineBreaks);
 						if (linesInsertedEvent !== null) {
 							eventsCollector.emitViewEvent(linesInsertedEvent);
-							this.viewLayout.onLinesInserted(linesInsertedEvent.fromLineNumber, linesInsertedEvent.toLineNumber, this._getCustomLineHeightsForLines(change.fromLineNumberPostEdit, change.toLineNumberPostEdit));
+							this.viewLayout.onLinesInserted(linesInsertedEvent.fromLineNumber, linesInsertedEvent.toLineNumber);
+							deferredCustomLineHeightRanges.push({ fromLineNumber: change.fromLineNumberPostEdit, toLineNumber: change.toLineNumberPostEdit });
 						}
 						hadOtherModelChange = true;
 						break;
@@ -394,11 +401,13 @@ export class ViewModel extends Disposable implements IViewModel {
 						}
 						if (linesInsertedEvent) {
 							eventsCollector.emitViewEvent(linesInsertedEvent);
-							this.viewLayout.onLinesInserted(linesInsertedEvent.fromLineNumber, linesInsertedEvent.toLineNumber, this._getCustomLineHeightsForLines(change.lineNumberPostEdit, change.lineNumberPostEdit));
+							this.viewLayout.onLinesInserted(linesInsertedEvent.fromLineNumber, linesInsertedEvent.toLineNumber);
+							deferredCustomLineHeightRanges.push({ fromLineNumber: change.lineNumberPostEdit, toLineNumber: change.lineNumberPostEdit });
 						}
 						if (linesDeletedEvent) {
 							eventsCollector.emitViewEvent(linesDeletedEvent);
 							this.viewLayout.onLinesDeleted(linesDeletedEvent.fromLineNumber, linesDeletedEvent.toLineNumber);
+							deferredCustomLineHeightRanges.push({ fromLineNumber: change.lineNumberPostEdit, toLineNumber: change.lineNumberPostEdit });
 						}
 						break;
 					}
@@ -412,6 +421,19 @@ export class ViewModel extends Disposable implements IViewModel {
 			if (versionId !== null) {
 				this._lines.acceptVersionId(versionId);
 			}
+
+			// Apply deferred custom line heights now that projections are stable
+			if (deferredCustomLineHeightRanges.length > 0) {
+				this.viewLayout.changeSpecialLineHeights((accessor: ILineHeightChangeAccessor) => {
+					for (const range of deferredCustomLineHeightRanges) {
+						const customLineHeights = this._getCustomLineHeightsForLines(range.fromLineNumber, range.toLineNumber);
+						for (const data of customLineHeights) {
+							accessor.insertOrChangeCustomLineHeight(data.decorationId, data.startLineNumber, data.endLineNumber, data.lineHeight);
+						}
+					}
+				});


deferredCustomLineHeightRanges can accumulate duplicate/overlapping ranges in a single edit batch, causing repeated getCustomLineHeightsDecorationsInRange queries and repeated insertOrChangeCustomLineHeight calls for the same decoration IDs. Consider deduplicating/merging ranges (or collecting decoration IDs) before querying/applying to avoid avoidable work on large edit batches.

Copilot · 2026-02-26T13:43:24Z

src/vs/editor/test/common/viewLayout/lineHeights.test.ts

+	test('deleting line 2 with lineHeightsRemoved re-adding at line 1 moves special line to line 1', () => {
+		const manager = new LineHeightsManager(10, []);
+		manager.insertOrChangeCustomLineHeight('dec1', 2, 2, 20);
+		assert.strictEqual(manager.heightForLineNumber(2), 20);
+		manager.onLinesDeleted(2, 2);
+		assert.strictEqual(manager.heightForLineNumber(1), 20);


This new test’s expectation doesn’t match the current LineHeightsManager.onLinesDeleted behavior: deleting line 2 will not move an existing custom height from line 2 to line 1 (it collapses to fromLineNumber in existing tests/comments in this file). As written, this test should fail. If you intend to verify the “remove + re-add at a different line” scenario, the test needs to explicitly simulate that (e.g., remove the decoration ID and then insert/change it at line 1 after the delete), or adjust the expected line number.

Suggested change

test('deleting line 2 with lineHeightsRemoved re-adding at line 1 moves special line to line 1', () => {

const manager = new LineHeightsManager(10, []);

manager.insertOrChangeCustomLineHeight('dec1', 2, 2, 20);

assert.strictEqual(manager.heightForLineNumber(2), 20);

manager.onLinesDeleted(2, 2);

assert.strictEqual(manager.heightForLineNumber(1), 20);

test('deleting line 2 keeps special line height at fromLineNumber (line 2)', () => {

const manager = new LineHeightsManager(10, []);

manager.insertOrChangeCustomLineHeight('dec1', 2, 2, 20);

assert.strictEqual(manager.heightForLineNumber(2), 20);

manager.onLinesDeleted(2, 2);

// After deletion, the decoration collapses to fromLineNumber (2), not moved to line 1

assert.strictEqual(manager.heightForLineNumber(1), 10);

assert.strictEqual(manager.heightForLineNumber(2), 20);

Copilot · 2026-02-26T13:43:25Z

src/vs/editor/test/common/viewLayout/lineHeights.test.ts

 		assert.strictEqual(manager.getAccumulatedLineHeightsIncludingLineNumber(6), 110);
 	});
+
+	test('deleting line 2 with lineHeightsRemoved re-adding at line 1 moves special line to line 1', () => {


The new test title is hard to parse and grammatically off ("with lineHeightsRemoved re-adding..."). Please reword it to clearly describe the scenario and expected outcome (e.g. mention deletion, then decoration removal/re-add, and what line number should end up special).

Suggested change

test('deleting line 2 with lineHeightsRemoved re-adding at line 1 moves special line to line 1', () => {

test('deleting line 2 and re-adding its custom height on line 1 makes line 1 special', () => {

…297999)" This reverts commit 4dfa19f.

aiday-mar added 17 commits January 22, 2026 13:08

adding lineHeightsAdded array

9f34b7c

polish

02f99be

fixing the test

dc40e0a

renaming to lineHeightAdded

ef00e4c

adding code to update the line heights on deletion

9cafcda

polishing

7bf9a9e

Merge branch 'main' into vital-termite

0362591

polishing

46d48b0

polishing

d08e316

using same line for from and to

1edae2d

Merge branch main into vital-termite

a01a5c4

adding unit test

6582ccb

Merge branch 'main' into vital-termite

8fbeb81

fixing merge

59eacbd

fixing tests

51e8111

modifying the comment

e47474f

applying changes after

84b68a6

Copilot AI review requested due to automatic review settings February 26, 2026 13:37

aiday-mar self-assigned this Feb 26, 2026

Copilot started reviewing on behalf of aiday-mar February 26, 2026 13:38 View session

removing comments

7877883

Copilot AI reviewed Feb 26, 2026

View reviewed changes

aiday-mar added 2 commits February 26, 2026 14:45

fixing the tests

6184549

renaming the variable

83d8e0b

aiday-mar requested a review from alexdima February 26, 2026 14:01

aiday-mar marked this pull request as ready for review February 26, 2026 14:01

vs-code-engineering bot added this to the February 2026 milestone Feb 26, 2026

austindyoung mentioned this pull request Feb 26, 2026

[mirror] microsoft/vscode#297999 Applying custom line heights after the edits are processed austindyoung/vscode-driftfence-mirror-fork#191

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alexdima approved these changes Feb 26, 2026

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alexdima merged commit 4dfa19f into main Feb 26, 2026
20 checks passed

alexdima deleted the defeated-dingo branch February 26, 2026 22:28

aiday-mar added a commit that referenced this pull request Feb 27, 2026

Revert "Applying custom line heights after the edits are processed (#…

3d8b14a

…297999)" This reverts commit 4dfa19f.

aiday-mar mentioned this pull request Feb 27, 2026

Revert "Applying custom line heights after the edits are processed" #298216

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Applying custom line heights after the edits are processed#297999

Applying custom line heights after the edits are processed#297999
alexdima merged 20 commits intomainfrom
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aiday-mar commented Feb 26, 2026 •

edited

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	test('deleting line 2 with lineHeightsRemoved re-adding at line 1 moves special line to line 1', () => {
	test('deleting line 2 and re-adding its custom height on line 1 makes line 1 special', () => {

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aiday-mar commented Feb 26, 2026 •

edited

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