fix #31619

src/vs/editor/contrib/snippet/snippetSession.ts

@@ -106,18 +106,21 @@ export class OneSnippet {
 			}
 		}
 
+		let skipThisPlaceholder = false;
 		if (fwd === true && this._placeholderGroupsIdx < this._placeholderGroups.length - 1) {
 			this._placeholderGroupsIdx += 1;
+			skipThisPlaceholder = true;
 
 		} else if (fwd === false && this._placeholderGroupsIdx > 0) {
 			this._placeholderGroupsIdx -= 1;
+			skipThisPlaceholder = true;
 
 		} else {
 			// the selection of the current placeholder might
 			// not acurate any more -> simply restore it
 		}
 
-		return this._editor.getModel().changeDecorations(accessor => {
+		const newSelections = this._editor.getModel().changeDecorations(accessor => {
 
 			const activePlaceholders = new Set<Placeholder>();
 
@@ -132,6 +135,11 @@ export class OneSnippet {
 				const range = this._editor.getModel().getDecorationRange(id);
 				selections.push(new Selection(range.startLineNumber, range.startColumn, range.endLineNumber, range.endColumn));
 
+				// consider to skip this placeholder index when the decoration
+				// range is empty but when the placeholder wasn't. that's a strong
+				// hint that the placeholder has been deleted. (all placeholder must match this)
+				skipThisPlaceholder = skipThisPlaceholder && (range.isEmpty() && placeholder.toString().length > 0);
+
 				accessor.changeDecorationOptions(id, placeholder.isFinalTabstop ? OneSnippet._decor.activeFinal : OneSnippet._decor.active);
 				activePlaceholders.add(placeholder);
 
@@ -152,6 +160,8 @@ export class OneSnippet {
 
 			return selections;
 		});
+
+		return !skipThisPlaceholder ? newSelections : this.move(fwd);
 	}
 
 	get isAtFirstPlaceholder() {

src/vs/editor/contrib/snippet/test/snippetController2.test.ts

@@ -12,6 +12,7 @@ import { TextModel } from 'vs/editor/common/model/textModel';
 import { MockContextKeyService } from 'vs/platform/keybinding/test/common/mockKeybindingService';
 import { ICodeEditor } from 'vs/editor/browser/editorBrowser';
 import { NullLogService } from 'vs/platform/log/common/log';
+import { Handler } from 'vs/editor/common/editorCommon';
 
 suite('SnippetController2', function () {
 
@@ -347,4 +348,19 @@ suite('SnippetController2', function () {
 		assertSelections(editor, new Selection(1, 49, 1, 49));
 		assertContextKeys(contextKeys, false, false, false);
 	});
+
+	test('Must tab through deleted tab stops in snippets #31619', function () {
+		const ctrl = new SnippetController2(editor, logService, contextKeys);
+		model.setValue('');
+		editor.setSelection(new Selection(1, 1, 1, 1));
+		ctrl.insert('foo${1:a${2:bar}baz}end$0');
+		assertSelections(editor, new Selection(1, 4, 1, 11));
+
+		editor.trigger('test', Handler.Cut, null);
+		assertSelections(editor, new Selection(1, 4, 1, 4));
+
+		ctrl.next();
+		assertSelections(editor, new Selection(1, 7, 1, 7));
+		assertContextKeys(contextKeys, false, false, false);
+	});
 });