From e3abbc26c051bbd241effd037c7b0afb6902e98e Mon Sep 17 00:00:00 2001
From: Moti Zilberman <moti@meta.com>
Date: Thu, 22 Jun 2023 00:10:48 -0700
Subject: [PATCH] Prevent LogBox from crashing on long messages (#38005)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/38005

Fixes https://github.com/facebook/react-native/issues/32093 by guarding the expensive `BABEL_CODE_FRAME_ERROR_FORMAT` regex with a cheaper initial scan. (Longer term, we should reduce our reliance on string parsing and propagate more structured errors.)

Changelog: [General][Fixed] Prevent LogBox from crashing on very long messages

Reviewed By: GijsWeterings

Differential Revision: D46892454

fbshipit-source-id: df0ab3c042c5b9be9c3933f429a06e666a2a673b
---
 flow-typed/npm/ansi-regex_v5.x.x.js           | 14 ++++
 .../Libraries/LogBox/Data/parseLogBoxLog.js   | 72 +++++++++++++------
 packages/react-native/package.json            |  1 +
 3 files changed, 66 insertions(+), 21 deletions(-)
 create mode 100644 flow-typed/npm/ansi-regex_v5.x.x.js

diff --git a/flow-typed/npm/ansi-regex_v5.x.x.js b/flow-typed/npm/ansi-regex_v5.x.x.js
new file mode 100644
index 00000000000000..150902f4a12e6c
--- /dev/null
+++ b/flow-typed/npm/ansi-regex_v5.x.x.js
@@ -0,0 +1,14 @@
+/**
+ * @flow strict
+ * @format
+ */
+
+declare module 'ansi-regex' {
+  declare export type Options = {
+    /**
+     * Match only the first ANSI escape.
+     */
+    +onlyFirst?: boolean,
+  };
+  declare export default function ansiRegex(options?: Options): RegExp;
+}
diff --git a/packages/react-native/Libraries/LogBox/Data/parseLogBoxLog.js b/packages/react-native/Libraries/LogBox/Data/parseLogBoxLog.js
index b41bade7fd0be5..744fa5e4e367ef 100644
--- a/packages/react-native/Libraries/LogBox/Data/parseLogBoxLog.js
+++ b/packages/react-native/Libraries/LogBox/Data/parseLogBoxLog.js
@@ -14,12 +14,38 @@ import type {LogBoxLogData} from './LogBoxLog';
 import parseErrorStack from '../../Core/Devtools/parseErrorStack';
 import UTFSequence from '../../UTFSequence';
 import stringifySafe from '../../Utilities/stringifySafe';
+import ansiRegex from 'ansi-regex';
+
+const ANSI_REGEX = ansiRegex().source;
 
 const BABEL_TRANSFORM_ERROR_FORMAT =
   /^(?:TransformError )?(?:SyntaxError: |ReferenceError: )(.*): (.*) \((\d+):(\d+)\)\n\n([\s\S]+)/;
+
+// https://github.com/babel/babel/blob/33dbb85e9e9fe36915273080ecc42aee62ed0ade/packages/babel-code-frame/src/index.ts#L183-L184
+const BABEL_CODE_FRAME_MARKER_PATTERN = new RegExp(
+  [
+    // Beginning of a line (per 'm' flag)
+    '^',
+    // Optional ANSI escapes for colors
+    `(?:${ANSI_REGEX})*`,
+    // Marker
+    '>',
+    // Optional ANSI escapes for colors
+    `(?:${ANSI_REGEX})*`,
+    // Left padding for line number
+    ' +',
+    // Line number
+    '[0-9]+',
+    // Gutter
+    ' \\|',
+  ].join(''),
+  'm',
+);
+
 const BABEL_CODE_FRAME_ERROR_FORMAT =
   // eslint-disable-next-line no-control-regex
   /^(?:TransformError )?(?:.*):? (?:.*?)(\/.*): ([\s\S]+?)\n([ >]{2}[\d\s]+ \|[\s\S]+|\u{001b}[\s\S]+)/u;
+
 const METRO_ERROR_FORMAT =
   /^(?:InternalError Metro has encountered an error:) (.*): (.*) \((\d+):(\d+)\)\n\n([\s\S]+)/u;
 
@@ -243,28 +269,32 @@ export function parseLogBoxException(
     };
   }
 
-  const babelCodeFrameError = message.match(BABEL_CODE_FRAME_ERROR_FORMAT);
+  // Perform a cheap match first before trying to parse the full message, which
+  // can get expensive for arbitrary input.
+  if (BABEL_CODE_FRAME_MARKER_PATTERN.test(message)) {
+    const babelCodeFrameError = message.match(BABEL_CODE_FRAME_ERROR_FORMAT);
 
-  if (babelCodeFrameError) {
-    // Codeframe errors are thrown from any use of buildCodeFrameError.
-    const [fileName, content, codeFrame] = babelCodeFrameError.slice(1);
-    return {
-      level: 'syntax',
-      stack: [],
-      isComponentError: false,
-      componentStack: [],
-      codeFrame: {
-        fileName,
-        location: null, // We are not given the location.
-        content: codeFrame,
-      },
-      message: {
-        content,
-        substitutions: [],
-      },
-      category: `${fileName}-${1}-${1}`,
-      extraData: error.extraData,
-    };
+    if (babelCodeFrameError) {
+      // Codeframe errors are thrown from any use of buildCodeFrameError.
+      const [fileName, content, codeFrame] = babelCodeFrameError.slice(1);
+      return {
+        level: 'syntax',
+        stack: [],
+        isComponentError: false,
+        componentStack: [],
+        codeFrame: {
+          fileName,
+          location: null, // We are not given the location.
+          content: codeFrame,
+        },
+        message: {
+          content,
+          substitutions: [],
+        },
+        category: `${fileName}-${1}-${1}`,
+        extraData: error.extraData,
+      };
+    }
   }
 
   if (message.match(/^TransformError /)) {
diff --git a/packages/react-native/package.json b/packages/react-native/package.json
index 67225d5695f41f..d7fb83ab397cbf 100644
--- a/packages/react-native/package.json
+++ b/packages/react-native/package.json
@@ -105,6 +105,7 @@
     "@react-native/virtualized-lists": "^0.73.0",
     "abort-controller": "^3.0.0",
     "anser": "^1.4.9",
+    "ansi-regex": "^5.0.0",
     "base64-js": "^1.5.1",
     "deprecated-react-native-prop-types": "4.1.0",
     "event-target-shim": "^5.0.1",