Fix #3874: preserve escaped commas in snippet literals (#4436)

* Fix #3874: preserve escaped commas in snippet literals

* Add test for #3874 snippet escaping

---------

Co-authored-by: MEHER SRUJANA MATCHA <mehersrujana.matcha@ibm.com>

Author: MeherSru

src/extension.ts

@@ -1325,8 +1325,8 @@ function registerRestartJavaLanguageServerCommand(context: ExtensionContext) {
 	}));
 }
 
-function escapeSnippetLiterals(value: string): string {
+export function escapeSnippetLiterals(value: string): string {
     return value
-        .replace(/\\/g, '\\\\')       // Escape backslashes
+        .replace(/\\(?!,)/g, '\\\\')       // Escape backslashes, but preserve escaped commas
         .replace(/\$(?!\{)/g, '\\$'); // Escape $ only if NOT followed by {
 }

test/standard-mode-suite/extension.test.ts

@@ -7,6 +7,7 @@ import { Commands } from '../../src/commands';
 import * as java from '../../src/javaServerStarter';
 import * as plugin from '../../src/plugin';
 import * as requirements from '../../src/requirements';
+import { escapeSnippetLiterals } from '../../src/extension';
 
 suite('Java Language Extension - Standard', () => {
 
@@ -233,4 +234,10 @@ suite('Java Language Extension - Standard', () => {
 		assert(java.hasDebugFlag(['foo', '--debug=1234']));
 		assert(java.hasDebugFlag(['foo', '--debug-brk=1234']));
 	});
+
+	test('should preserve escaped commas in code action snippets', () => {
+		const snippet = '${1|HashMap<Integer\\,Integer>,Map<Integer\\,Integer>|} ${2:x} = new HashMap<Integer, Integer>();';
+
+		assert.equal(escapeSnippetLiterals(snippet), snippet);
+	});
 });