From 62ea244b669677e9122b1cb2a1827627ec918e5d Mon Sep 17 00:00:00 2001
From: Andreas Madsen <amwebdk@gmail.com>
Date: Fri, 3 Aug 2012 16:37:23 +0200
Subject: [PATCH 1/2] util: export a new bindHistory function

In async operations the history from the tick there called the async function
is lost. This method binds the call-tick call-stack to the error object there
was returned in the callback function as first argument
---
 lib/util.js | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)

diff --git a/lib/util.js b/lib/util.js
index 65888920c8d5..50342b049ba5 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -519,6 +519,76 @@ exports.pump = function(readStream, writeStream, callback) {
   });
 };
 
+// This will bind the current history stack, to the async
+// callback error object
+exports._bindHistory = function (callback) {
+  var history = new Error();
+
+  return function (error) {
+    // merge history intro error
+    if (isError(error)) appendHistory(error, history);
+
+    callback.apply(null, arguments);
+  };
+};
+
+function appendHistory(error, history) {
+  // get the current error.stack handler
+  var orig = Error.prepareStackTrace;
+
+  // get the history stack list
+  Error.prepareStackTrace = function (errorObject, stackObject) {
+    return stackObject;
+  };
+  var historyStack = history.stack;
+
+  // Include the history stack list in the error
+  Error.prepareStackTrace = function (errorObject, stackObject) {
+    var modifiedStack = historyStack.slice(1).concat(stackObject);
+
+    if (typeof orig === 'function') {
+      return orig(errorObject, modifiedStack);
+    } else {
+      return FormatStackTrace(errorObject, modifiedStack);
+    }
+  };
+  // This will need to be performed, so Error.prepareStackTrace is executed
+  var errorStack = error.stack;
+
+  // the returned error.stack value is cached, so it is safe to restore
+  // the error.stack handler
+  Error.prepareStackTrace = orig;
+}
+
+// copyed from deps/v8/src/messages.js
+function FormatStackTrace(error, frames) {
+  var lines = [];
+  try {
+    lines.push(error.toString());
+  } catch (e) {
+    try {
+      lines.push("<error: " + e + ">");
+    } catch (ee) {
+      lines.push("<error>");
+    }
+  }
+  for (var i = 0; i < frames.length; i++) {
+    var frame = frames[i];
+    var line;
+    try {
+      line = frame.toString();
+    } catch (e) {
+      try {
+        line = "<error: " + e + ">";
+      } catch (ee) {
+        // Any code that reaches this point is seriously nasty!
+        line = "<error>";
+      }
+    }
+    lines.push("    at " + line);
+  }
+  return lines.join("\n");
+}
 
 /**
  * Inherit the prototype methods from one constructor into another.

From 6ebdae13d8c6acbef6b01e9ed44e9acbbb498146 Mon Sep 17 00:00:00 2001
From: Andreas Madsen <amwebdk@gmail.com>
Date: Fri, 3 Aug 2012 16:55:15 +0200
Subject: [PATCH 2/2] fs: improve error call stack

---
 lib/fs.js | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/lib/fs.js b/lib/fs.js
index 7c622375e3ab..d339be9d0bff 100644
--- a/lib/fs.js
+++ b/lib/fs.js
@@ -293,9 +293,7 @@ function makeCallback(cb) {
     return function() {};
   }
 
-  return function() {
-    return cb.apply(null, arguments);
-  };
+  return util._bindHistory(cb);
 }
 
 
@@ -362,7 +360,7 @@ fs.read = function(fd, buffer, offset, length, position, callback) {
     callback && callback(err, bytesRead || 0, buffer);
   }
 
-  binding.read(fd, buffer, offset, length, position, wrapper);
+  binding.read(fd, buffer, offset, length, position, makeCallback(wrapper));
 };
 
 fs.readSync = function(fd, buffer, offset, length, position) {
@@ -412,7 +410,7 @@ fs.write = function(fd, buffer, offset, length, position, callback) {
     callback && callback(err, written || 0, buffer);
   }
 
-  binding.write(fd, buffer, offset, length, position, wrapper);
+  binding.write(fd, buffer, offset, length, position, makeCallback(wrapper));
 };
 
 fs.writeSync = function(fd, buffer, offset, length, position) {