fix behaviour with multiline vs singleline snippets and their final cursor position, #11742

src/vs/editor/contrib/snippet/common/snippetController.ts

@@ -484,7 +484,7 @@ export class SnippetController {
 		const edits: editorCommon.IIdentifiedSingleEditOperation[] = [];
 		const selections = this._editor.getSelections();
 		let lineDelta = 0;
-		let columnDelta = 0;
+		let columnDeltaOrValue = 0;
 
 		for (let i = 0; i < selections.length; i++) {
 			let {adaptedSnippet, typeRange} = SnippetController._prepareSnippet(this._editor, selections[i], snippet, overwriteBefore, overwriteAfter, stripPrefix);
@@ -492,12 +492,13 @@ export class SnippetController {
 
 			if (i === 0 && snippet.isSingleTabstopOnly) {
 				const finalCursorPos = SnippetController._getSnippetCursorOnly(adaptedSnippet);
-				const editEnd = typeRange.getEndPosition();
-				editEnd.lineNumber += adaptedSnippet.lines.length - 1;
-				editEnd.column = adaptedSnippet.lines[adaptedSnippet.lines.length - 1].length + 1;
 
-				lineDelta = finalCursorPos.lineNumber - editEnd.lineNumber;
-				columnDelta = finalCursorPos.column - editEnd.column;
+				lineDelta = finalCursorPos.lineNumber - typeRange.startLineNumber;
+				if (lineDelta === 0) {
+					columnDeltaOrValue = finalCursorPos.column - typeRange.startColumn;
+				} else {
+					columnDeltaOrValue = finalCursorPos.column;
+				}
 			}
 		}
 
@@ -509,11 +510,15 @@ export class SnippetController {
 
 			return inverseEdits.map((edit, i) => {
 
-				let {endLineNumber, endColumn} = edit.range;
-				endLineNumber += lineDelta;
-				endColumn += columnDelta;
+				let {startLineNumber, startColumn} = edit.range;
+				if (lineDelta === 0) {
+					startColumn += columnDeltaOrValue;
+				} else {
+					startLineNumber += lineDelta;
+					startColumn += columnDeltaOrValue;
+				}
 
-				return new Selection(endLineNumber, endColumn, endLineNumber, endColumn);
+				return new Selection(startLineNumber, startColumn, startLineNumber, startColumn);
 			});
 		};
 

src/vs/editor/contrib/snippet/test/common/snippetController.test.ts

@@ -281,5 +281,18 @@ suite('SnippetController', () => {
 			assert.ok(first.equalsRange({ startLineNumber: 2, startColumn: 1, endLineNumber: 2, endColumn: 1 }), first.toString());
 			assert.ok(second.equalsRange({ startLineNumber: 4, startColumn: 1, endLineNumber: 4, endColumn: 1 }), second.toString());
 		});
+
+		snippetTest((editor, cursor, codeSnippet, snippetController) => {
+			editor.setSelections([
+				new Selection(2, 7, 2, 7)
+			]);
+
+			codeSnippet = CodeSnippet.fromInternal('xx{{}}yy');
+			snippetController.run(codeSnippet, 1, 0, false);
+
+			assert.equal(editor.getSelections().length, 1);
+			const [first] = editor.getSelections();
+			assert.ok(first.equalsRange({ startLineNumber: 2, startColumn: 8, endLineNumber: 2, endColumn: 8 }), first.toString());
+		});
 	});
 });
\ No newline at end of file