Merge pull request #41 from drauggres/master

formatting error created in wrapper and using its cached_trace

Author: mattinsler

dist/longjohn.js

@@ -71,7 +71,7 @@ prepareStackTrace = (error, structured_stack_trace) ->
     error.__previous__ = current_trace_error if !error.__previous__? and in_prepare is 1
 
     if error.__previous__?
-      previous_stack = error.__previous__.stack
+      previous_stack = error.__previous__.__cached_trace__
       if previous_stack?.length > 0
         error.__cached_trace__.push(create_callsite(exports.empty_frame))
         error.__cached_trace__.push(previous_stack...)
@@ -90,7 +90,15 @@ limit_frames = (stack) ->
   while previous? and count > 1
     previous = previous.__previous__
     --count
-  delete previous.__previous__ if previous?
+  if previous?
+    which_previous_must_delete = previous
+    if previous?.__previous__?.__cached_trace__
+      len = previous.__previous__.__cached_trace__.length
+      previous = stack
+      while previous? and previous != which_previous_must_delete.__previous__
+        previous.__cached_trace__.length -= (len+1)
+        previous = previous.__previous__
+    delete previous.__previous__
 
 ERROR_ID = 1
 
@@ -111,6 +119,7 @@ wrap_callback = (callback, location) ->
   trace_error.__location__ = location
   trace_error.__previous__ = current_trace_error
   trace_error.__trace_count__ = if current_trace_error? then current_trace_error.__trace_count__ + 1 else 1
+  trace_error.stack
 
   limit_frames(trace_error)
 

lib/longjohn.coffee

@@ -9,7 +9,9 @@ describe 'longjohn', ->
     fs = require('fs')
 
     fs.readFile 'not_there.txt', 'utf8', (err, text) ->
-      return done() if err? and err instanceof Error and err.stack is "Error: ENOENT, open 'not_there.txt'"
+      return done() if err? and err instanceof Error and
+      (err.stack is "Error: ENOENT, open 'not_there.txt'" or
+       err.stack is "Error: ENOENT, open 'not_there.txt'\n    at Error (native)")
       assert.fail()
 
   it 'should track frames across setTimeout', (done) ->