fix #78883

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

@@ -667,16 +667,24 @@ export class SnippetParser {
 		if (this._token.type === TokenType.EOF) {
 			return false;
 		}
-		let start = this._token;
-		while (this._token.type !== type) {
+		let res = '';
+		let pos = this._token.pos;
+		let prevToken = <Token>{ type: TokenType.EOF, pos: 0, len: 0 };
+
+		while (this._token.type !== type || prevToken.type === TokenType.Backslash) {
+			if (this._token.type === type) {
+				res += this._scanner.value.substring(pos, prevToken.pos);
+				pos = this._token.pos;
+			}
+			prevToken = this._token;
 			this._token = this._scanner.next();
 			if (this._token.type === TokenType.EOF) {
 				return false;
 			}
 		}
-		let value = this._scanner.value.substring(start.pos, this._token.pos);
+		res += this._scanner.value.substring(pos, this._token.pos);
 		this._token = this._scanner.next();
-		return value;
+		return res;
 	}
 
 	private _parse(marker: Marker): boolean {

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

@@ -754,4 +754,17 @@ suite('SnippetParser', () => {
 		let snippet = new SnippetParser().parse('namespace ${TM_DIRECTORY/[\\/]/\\\\/g};');
 		assertMarker(snippet, Text, Variable, Text);
 	});
+
+	test('Snippet cannot escape closing bracket inside conditional insertion variable replacement #78883', function () {
+
+		let snippet = new SnippetParser().parse('${TM_DIRECTORY/(.+)/${1:+import { hello \\} from world}/}');
+		let variable = <Variable>snippet.children[0];
+		assert.equal(snippet.children.length, 1);
+		assert.ok(variable instanceof Variable);
+		assert.ok(variable.transform);
+		assert.equal(variable.transform!.children.length, 1);
+		assert.ok(variable.transform!.children[0] instanceof FormatString);
+		assert.equal((<FormatString>variable.transform!.children[0]).ifValue, 'import { hello } from world');
+		assert.equal((<FormatString>variable.transform!.children[0]).elseValue, undefined);
+	});
 });