From 2986982459a939531ea552660e0d729f0044c318 Mon Sep 17 00:00:00 2001
From: bcoe <bencoe@google.com>
Date: Tue, 31 Dec 2019 09:24:43 -0800
Subject: [PATCH] errors: support prepareSourceMap with source-maps

Adds support for Error.prepareStackTrace override, when
--enable-source-maps is set.

PR-URL: https://github.com/nodejs/node/pull/31143
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
---
 lib/internal/errors.js                        | 32 ++++++++++++-------
 .../source_map/prepare_stack_trace.js         | 10 +++++-
 .../test-error-prepare-stack-trace.js         | 19 +++++++++++
 3 files changed, 49 insertions(+), 12 deletions(-)
 create mode 100644 test/parallel/test-error-prepare-stack-trace.js

diff --git a/lib/internal/errors.js b/lib/internal/errors.js
index 05b92ab9b082f9..2e851867c74a51 100644
--- a/lib/internal/errors.js
+++ b/lib/internal/errors.js
@@ -20,6 +20,7 @@ const { kMaxLength } = internalBinding('buffer');
 const MainContextError = Error;
 const ErrorToString = Error.prototype.toString;
 const overrideStackTrace = new WeakMap();
+const kNoOverride = Symbol('kNoOverride');
 const prepareStackTrace = (globalThis, error, trace) => {
   // API for node internals to override error stack formatting
   // without interfering with userland code.
@@ -29,6 +30,23 @@ const prepareStackTrace = (globalThis, error, trace) => {
     return f(error, trace);
   }
 
+  const globalOverride =
+    maybeOverridePrepareStackTrace(globalThis, error, trace);
+  if (globalOverride !== kNoOverride) return globalOverride;
+
+  // Normal error formatting:
+  //
+  // Error: Message
+  //     at function (file)
+  //     at file
+  const errorString = ErrorToString.call(error);
+  if (trace.length === 0) {
+    return errorString;
+  }
+  return `${errorString}\n    at ${trace.join('\n    at ')}`;
+};
+
+const maybeOverridePrepareStackTrace = (globalThis, error, trace) => {
   // Polyfill of V8's Error.prepareStackTrace API.
   // https://crbug.com/v8/7848
   // `globalThis` is the global that contains the constructor which
@@ -43,19 +61,9 @@ const prepareStackTrace = (globalThis, error, trace) => {
     return MainContextError.prepareStackTrace(error, trace);
   }
 
-  // Normal error formatting:
-  //
-  // Error: Message
-  //     at function (file)
-  //     at file
-  const errorString = ErrorToString.call(error);
-  if (trace.length === 0) {
-    return errorString;
-  }
-  return `${errorString}\n    at ${trace.join('\n    at ')}`;
+  return kNoOverride;
 };
 
-
 let excludedStackFn;
 
 // Lazily loaded
@@ -683,7 +691,9 @@ module.exports = {
   SystemError,
   // This is exported only to facilitate testing.
   E,
+  kNoOverride,
   prepareStackTrace,
+  maybeOverridePrepareStackTrace,
   overrideStackTrace,
   kEnhanceStackBeforeInspector,
   fatalExceptionStackEnhancers
diff --git a/lib/internal/source_map/prepare_stack_trace.js b/lib/internal/source_map/prepare_stack_trace.js
index d6c5fce60a29e3..91bedcb266be70 100644
--- a/lib/internal/source_map/prepare_stack_trace.js
+++ b/lib/internal/source_map/prepare_stack_trace.js
@@ -2,7 +2,11 @@
 
 const debug = require('internal/util/debuglog').debuglog('source_map');
 const { findSourceMap } = require('internal/source_map/source_map_cache');
-const { overrideStackTrace } = require('internal/errors');
+const {
+  kNoOverride,
+  overrideStackTrace,
+  maybeOverridePrepareStackTrace
+} = require('internal/errors');
 
 // Create a prettified stacktrace, inserting context from source maps
 // if possible.
@@ -17,6 +21,10 @@ const prepareStackTrace = (globalThis, error, trace) => {
     return f(error, trace);
   }
 
+  const globalOverride =
+    maybeOverridePrepareStackTrace(globalThis, error, trace);
+  if (globalOverride !== kNoOverride) return globalOverride;
+
   const { SourceMap } = require('internal/source_map/source_map');
   const errorString = ErrorToString.call(error);
 
diff --git a/test/parallel/test-error-prepare-stack-trace.js b/test/parallel/test-error-prepare-stack-trace.js
new file mode 100644
index 00000000000000..2ace9c8d71491d
--- /dev/null
+++ b/test/parallel/test-error-prepare-stack-trace.js
@@ -0,0 +1,19 @@
+// Flags: --enable-source-maps
+'use strict';
+
+require('../common');
+const assert = require('assert');
+
+// Error.prepareStackTrace() can be overridden with source maps enabled.
+{
+  let prepareCalled = false;
+  Error.prepareStackTrace = (_error, trace) => {
+    prepareCalled = true;
+  };
+  try {
+    throw new Error('foo');
+  } catch (err) {
+    err.stack;
+  }
+  assert(prepareCalled);
+}