Merge pull request microsoft#165635 from rwe/fix-deserialize-message

shellIntegrationAddon: fix broken `deserializeMessage()` implementation + add tests

Author: Tyriar

src/vs/platform/terminal/common/xterm/shellIntegrationAddon.ts

@@ -513,16 +513,12 @@ export class ShellIntegrationAddon extends Disposable implements IShellIntegrati
 }
 
 export function deserializeMessage(message: string): string {
-	let result = message.replace(/\\\\/g, '\\');
-	const deserializeRegex = /\\x([0-9a-f]{2})/i;
-	while (true) {
-		const match = result.match(deserializeRegex);
-		if (!match?.index || match.length < 2) {
-			break;
-		}
-		result = result.slice(0, match.index) + String.fromCharCode(parseInt(match[1], 16)) + result.slice(match.index + 4);
-	}
-	return result;
+	return message.replaceAll(
+		// Backslash ('\') followed by an escape operator: either another '\', or 'x' and two hex chars.
+		/\\(\\|x([0-9a-f]{2}))/gi,
+		// If it's a hex value, parse it to a character.
+		// Otherwise the operator is '\', which we return literally, now unescaped.
+		(_match: string, op: string, hex?: string) => hex ? String.fromCharCode(parseInt(hex, 16)) : op);
 }
 
 export function parseKeyValueAssignment(message: string): { key: string; value: string | undefined } {

src/vs/workbench/contrib/terminal/test/browser/xterm/shellIntegrationAddon.test.ts

@@ -7,7 +7,7 @@ import { Terminal } from 'xterm';
 import { strictEqual, deepStrictEqual, deepEqual } from 'assert';
 import { timeout } from 'vs/base/common/async';
 import * as sinon from 'sinon';
-import { parseKeyValueAssignment, parseMarkSequence, ShellIntegrationAddon } from 'vs/platform/terminal/common/xterm/shellIntegrationAddon';
+import { parseKeyValueAssignment, parseMarkSequence, deserializeMessage, ShellIntegrationAddon } from 'vs/platform/terminal/common/xterm/shellIntegrationAddon';
 import { ITerminalCapabilityStore, TerminalCapability } from 'vs/platform/terminal/common/capabilities/capabilities';
 import { TestInstantiationService } from 'vs/platform/instantiation/test/common/instantiationServiceMock';
 import { ILogService, NullLogService } from 'vs/platform/log/common/log';
@@ -257,6 +257,41 @@ suite('ShellIntegrationAddon', () => {
 	});
 });
 
+suite('deserializeMessage', () => {
+	// A single literal backslash, in order to avoid confusion about whether we are escaping test data or testing escapes.
+	const Backslash = '\\' as const;
+	const Newline = '\n' as const;
+	const Semicolon = ';' as const;
+
+	type TestCase = [title: string, input: string, expected: string];
+	const cases: TestCase[] = [
+		['empty', '', ''],
+		['basic', 'value', 'value'],
+		['space', 'some thing', 'some thing'],
+		['escaped backslash', `${Backslash}${Backslash}`, Backslash],
+		['non-initial escaped backslash', `foo${Backslash}${Backslash}`, `foo${Backslash}`],
+		['two escaped backslashes', `${Backslash}${Backslash}${Backslash}${Backslash}`, `${Backslash}${Backslash}`],
+		['escaped backslash amidst text', `Hello${Backslash}${Backslash}there`, `Hello${Backslash}there`],
+		['backslash escaped literally and as hex', `${Backslash}${Backslash} is same as ${Backslash}x5c`, `${Backslash} is same as ${Backslash}`],
+		['escaped semicolon', `${Backslash}x3b`, Semicolon],
+		['non-initial escaped semicolon', `foo${Backslash}x3b`, `foo${Semicolon}`],
+		['escaped semicolon (upper hex)', `${Backslash}x3B`, Semicolon],
+		['escaped backslash followed by literal "x3b" is not a semicolon', `${Backslash}${Backslash}x3b`, `${Backslash}x3b`],
+		['non-initial escaped backslash followed by literal "x3b" is not a semicolon', `foo${Backslash}${Backslash}x3b`, `foo${Backslash}x3b`],
+		['escaped backslash followed by escaped semicolon', `${Backslash}${Backslash}${Backslash}x3b`, `${Backslash}${Semicolon}`],
+		['escaped semicolon amidst text', `some${Backslash}x3bthing`, `some${Semicolon}thing`],
+		['escaped newline', `${Backslash}x0a`, Newline],
+		['non-initial escaped newline', `foo${Backslash}x0a`, `foo${Newline}`],
+		['escaped newline (upper hex)', `${Backslash}x0A`, Newline],
+		['escaped backslash followed by literal "x0a" is not a newline', `${Backslash}${Backslash}x0a`, `${Backslash}x0a`],
+		['non-initial escaped backslash followed by literal "x0a" is not a newline', `foo${Backslash}${Backslash}x0a`, `foo${Backslash}x0a`],
+	];
+
+	cases.forEach(([title, input, expected]) => {
+		test(title, () => strictEqual(deserializeMessage(input), expected));
+	});
+});
+
 test('parseKeyValueAssignment', () => {
 	type TestCase = [title: string, input: string, expected: [key: string, value: string | undefined]];
 	const cases: TestCase[] = [