search: intelligently normalize crlf in regex search

Fixes https://github.com/microsoft/vscode/issues/100569

package.json

@@ -67,6 +67,7 @@
     "vscode-nsfw": "1.2.9",
     "vscode-oniguruma": "1.3.1",
     "vscode-proxy-agent": "^0.5.2",
+    "vscode-regexpp": "^3.1.0",
     "vscode-ripgrep": "^1.11.0",
     "vscode-sqlite3": "4.0.10",
     "vscode-textmate": "5.2.0",
@@ -194,4 +195,4 @@
     "windows-mutex": "0.3.0",
     "windows-process-tree": "0.2.4"
   }
-}
+}

src/vs/workbench/services/search/node/ripgrepTextSearchEngine.ts

@@ -16,6 +16,7 @@ import { URI } from 'vs/base/common/uri';
 import { Progress } from 'vs/platform/progress/common/progress';
 import { IExtendedExtensionSearchOptions, SearchError, SearchErrorCode, serializeSearchError } from 'vs/workbench/services/search/common/search';
 import { Range, TextSearchComplete, TextSearchContext, TextSearchMatch, TextSearchOptions, TextSearchPreviewOptions, TextSearchQuery, TextSearchResult } from 'vs/workbench/services/search/common/searchExtTypes';
+import { RegExpParser, RegExpVisitor, AST as ReAST } from 'vscode-regexpp';
 import { rgPath } from 'vscode-ripgrep';
 import { anchorGlob, createTextSearchResult, IOutputChannel, Maybe } from './ripgrepSearchUtils';
 
@@ -541,10 +542,78 @@ export interface IRgSubmatch {
 
 export type IRgBytesOrText = { bytes: string } | { text: string };
 
+const isLookBehind = (node: ReAST.Node) => node.type === 'Assertion' && node.kind === 'lookbehind';
+
 export function fixRegexNewline(pattern: string): string {
-	// Replace an unescaped $ at the end of the pattern with \r?$
-	// Match $ preceded by none or even number of literal \
-	return pattern.replace(/(?<=[^\\]|^)(\\\\)*\\n/g, '$1\\r?\\n');
+	// we parse the pattern anew each tiem
+	let re: ReAST.Pattern;
+	try {
+		re = new RegExpParser().parsePattern(pattern);
+	} catch {
+		return pattern;
+	}
+
+	let output = '';
+	let lastEmittedIndex = 0;
+	const replace = (start: number, end: number, text: string) => {
+		output += pattern.slice(lastEmittedIndex, start) + text;
+		lastEmittedIndex = end;
+	};
+
+	const context: ReAST.Node[] = [];
+	const visitor = new RegExpVisitor({
+		onCharacterEnter(char) {
+			if (char.raw !== '\\n') {
+				return;
+			}
+
+			const parent = context[0];
+			if (!parent) {
+				// simple char, \n -> \r?\n
+				replace(char.start, char.end, '\\r?\\n');
+			} else if (context.some(isLookBehind)) {
+				// no-op in a lookbehind, see #100569
+			} else if (parent.type === 'CharacterClass') {
+				// in a bracket expr, [a-z\n] -> (?:[a-z]|\r?\n)
+				const otherContent = pattern.slice(parent.start + 1, char.start) + pattern.slice(char.end, parent.end - 1);
+				replace(parent.start, parent.end, otherContent === '' ? '\\r?\\n' : `(?:[${otherContent}]|\\r?\\n)`);
+			} else if (parent.type === 'Quantifier') {
+				replace(char.start, char.end, '(?:\\r?\\n)');
+			}
+		},
+		onQuantifierEnter(node) {
+			context.unshift(node);
+		},
+		onQuantifierLeave() {
+			context.shift();
+		},
+		onCharacterClassRangeEnter(node) {
+			context.unshift(node);
+		},
+		onCharacterClassRangeLeave() {
+			context.shift();
+		},
+		onCharacterClassEnter(node) {
+			context.unshift(node);
+		},
+		onCharacterClassLeave() {
+			context.shift();
+		},
+		onAssertionEnter(node) {
+			if (isLookBehind(node)) {
+				context.push(node);
+			}
+		},
+		onAssertionLeave(node) {
+			if (context[0] === node) {
+				context.shift();
+			}
+		},
+	});
+
+	visitor.visit(re);
+	output += pattern.slice(lastEmittedIndex);
+	return output;
 }
 
 export function fixNewline(pattern: string): string {

src/vs/workbench/services/search/test/node/ripgrepTextSearchEngine.test.ts

@@ -28,7 +28,24 @@ suite('RipgrepTextSearchEngine', () => {
 		assert.equal(unicodeEscapesToPCRE2(''), '');
 	});
 
-	test('fixRegexNewline', () => {
+	test('fixRegexNewline - src', () => {
+		const ttable = [
+			['foo', 'foo'],
+			['invalid(', 'invalid('],
+			['fo\\no', 'fo\\r?\\no'],
+			['f\\no\\no', 'f\\r?\\no\\r?\\no'],
+			['f[a-z\\n1]', 'f(?:[a-z1]|\\r?\\n)'],
+			['f[\\n-a]', 'f[\\n-a]'],
+			['(?<=\\n)\\w', '(?<=\\n)\\w'],
+			['fo\\n+o', 'fo(?:\\r?\\n)+o'],
+		];
+
+		for (const [input, expected] of ttable) {
+			assert.equal(fixRegexNewline(input), expected, `${input} -> ${expected}`);
+		}
+	});
+
+	test('fixRegexNewline - re', () => {
 		function testFixRegexNewline([inputReg, testStr, shouldMatch]: readonly [string, string, boolean]): void {
 			const fixed = fixRegexNewline(inputReg);
 			const reg = new RegExp(fixed);
@@ -48,10 +65,12 @@ suite('RipgrepTextSearchEngine', () => {
 
 			['foo\\n+abc', 'foo\r\nabc', true],
 			['foo\\n+abc', 'foo\n\n\nabc', true],
+			['foo\\n+abc', 'foo\r\n\r\n\r\nabc', true],
+			['foo[\\n-9]+abc', 'foo1abc', true],
 		] as const).forEach(testFixRegexNewline);
 	});
 
-	test('fixNewline', () => {
+	test('fixNewline - matching', () => {
 		function testFixNewline([inputReg, testStr, shouldMatch = true]: readonly [string, string, boolean?]): void {
 			const fixed = fixNewline(inputReg);
 			const reg = new RegExp(fixed);

yarn.lock

@@ -9735,6 +9735,11 @@ vscode-proxy-agent@^0.5.2:
     https-proxy-agent "^2.2.3"
     socks-proxy-agent "^4.0.1"
 
+vscode-regexpp@^3.1.0:
+  version "3.1.0"
+  resolved "https://registry.yarnpkg.com/vscode-regexpp/-/vscode-regexpp-3.1.0.tgz#42d059b6fffe99bd42939c0d013f632f0cad823f"
+  integrity sha512-pqtN65VC1jRLawfluX4Y80MMG0DHJydWhe5ZwMHewZD6sys4LbU6lHwFAHxeuaVE6Y6+xZOtAw+9hvq7/0ejkg==
+
 vscode-ripgrep@^1.11.0:
   version "1.11.0"
   resolved "https://registry.yarnpkg.com/vscode-ripgrep/-/vscode-ripgrep-1.11.0.tgz#2874adea1753545590a315f02f36bed05b9e2380"