Properly parse tracebacks with missing source. Resolves #30

.travis.yml

@@ -6,4 +6,4 @@ python:
   - "pypy"
 
 install: "pip install -r requirements-test.txt"
-script: "py.test --doctest-modules boltons"
+script: "py.test --doctest-modules boltons tests"

boltons/tbutils.py

@@ -27,6 +27,12 @@ import sys
 import linecache
 
 
+if str is bytes:  # py2
+    text = unicode
+else:  # py3
+    text = str
+
+
 # TODO: chaining primitives?  what are real use cases where these help?
 
 # TODO: print_* for backwards compatability
@@ -691,7 +697,7 @@ class ParsedException(object):
         Args:
             tb_str (str): The traceback text (:class:`unicode` or UTF-8 bytes)
         """
-        if not isinstance(tb_str, unicode):
+        if not isinstance(tb_str, text):
             tb_str = tb_str.decode('utf-8')
         tb_lines = tb_str.lstrip().splitlines()
 
@@ -717,21 +723,27 @@ class ParsedException(object):
             raise ValueError('unrecognized traceback string format')
 
         frames = []
-        for pair_idx in range(start_line, len(tb_lines), 2):
-            frame_line = tb_lines[pair_idx].strip()
+        line_no = start_line
+        while True:
+            frame_line = tb_lines[line_no].strip()
             frame_match = frame_re.match(frame_line)
             if frame_match:
                 frame_dict = frame_match.groupdict()
+                next_line = tb_lines[line_no + 1].strip()
+                if frame_re.match(next_line):
+                    frame_dict['source_line'] = ''
+                else:
+                    frame_dict['source_line'] = next_line
+                    line_no += 1
             else:
                 break
-            frame_dict['source_line'] = tb_lines[pair_idx + 1].strip()
+            line_no += 1
             frames.append(frame_dict)
 
-        exc_line_offset = start_line + len(frames) * 2
         try:
-            exc_line = tb_lines[exc_line_offset]
+            exc_line = tb_lines[line_no]
             exc_type, _, exc_msg = exc_line.partition(':')
-        except:
+        except Exception:
             exc_type, exc_msg = '', ''
 
         return cls(exc_type, exc_msg, frames)

tests/tbutils_test.py

@@ -0,0 +1,44 @@
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+from boltons.tbutils import ParsedException
+
+
+def test_normal_tb():
+    tb = '''\
+Traceback (most recent call last):
+  File "<string>", line 2, in _some_function
+    return some_other_function(1)
+  File "myfile.py", line 3, in some_other_function
+    return foo(bar, baz)
+MyException: ExceptionValue
+'''
+    parsed = ParsedException.from_string(tb)
+    assert parsed.exc_type == 'MyException'
+    assert parsed.exc_msg == ' ExceptionValue'
+    assert parsed.frames == [
+        {
+            'source_line': 'return some_other_function(1)',
+            'filepath': '<string>',
+            'lineno': '2',
+            'funcname': '_some_function'
+        },
+        {
+            'source_line': 'return foo(bar, baz)',
+            'filepath': 'myfile.py',
+            'lineno': '3',
+            'funcname': 'some_other_function',
+        }
+    ]
+
+
+def test_eval_tb():
+    tb = '''\
+Traceback (most recent call last):
+  File "<string>", line 2, in _some_function
+  File "myfile.py", line 3, in some_other_function
+    return foo(bar, baz)
+MyException: ExceptionValue
+'''
+    parsed = ParsedException.from_string(tb)
+    assert parsed.exc_type == 'MyException'

tox.ini

@@ -2,4 +2,4 @@
 envlist = py27,py34,pypy
 [testenv]
 deps = -rrequirements-test.txt
-commands = py.test --doctest-modules boltons
+commands = py.test --doctest-modules boltons tests