Rev 3980: Workaround a bug in pdb.post_mortem. (Andrew Bennetts) in file:///home/pqm/archives/thelove/bzr/%2Btrunk/

[Canonical.com Patch Queue Manager]

At file:///home/pqm/archives/thelove/bzr/%2Btrunk/

------------------------------------------------------------
revno: 3980
revision-id: pqm at pqm.ubuntu.com-20090204045809-piqek6zlyl0x5ncw
parent: pqm at pqm.ubuntu.com-20090203220822-5duwp3g1fj9kc9qd
parent: andrew.bennetts at canonical.com-20090204041915-a57oazgobkmuce9e
committer: Canonical.com Patch Queue Manager <pqm at pqm.ubuntu.com>
branch nick: +trunk
timestamp: Wed 2009-02-04 04:58:09 +0000
message:
  Workaround a bug in pdb.post_mortem. (Andrew Bennetts)
modified:
  NEWS                           NEWS-20050323055033-4e00b5db738777ff
  bzrlib/commands.py             bzr.py-20050309040720-d10f4714595cf8c3
    ------------------------------------------------------------
    revno: 3978.1.3
    revision-id: andrew.bennetts at canonical.com-20090204041915-a57oazgobkmuce9e
    parent: andrew.bennetts at canonical.com-20090204041014-ny61o8sh69ee2nnw
    committer: Andrew Bennetts <andrew.bennetts at canonical.com>
    branch nick: pdb-workaround
    timestamp: Wed 2009-02-04 15:19:15 +1100
    message:
      Add NEWS entry.
    modified:
      NEWS                           NEWS-20050323055033-4e00b5db738777ff
    ------------------------------------------------------------
    revno: 3978.1.2
    revision-id: andrew.bennetts at canonical.com-20090204041014-ny61o8sh69ee2nnw
    parent: andrew.bennetts at canonical.com-20090203055031-q0rde12116uv20t7
    committer: Andrew Bennetts <andrew.bennetts at canonical.com>
    branch nick: pdb-workaround
    timestamp: Wed 2009-02-04 15:10:14 +1100
    message:
      Only use pdb.post_mortem workaround with Pythons older than 2.6.
    modified:
      bzrlib/commands.py             bzr.py-20050309040720-d10f4714595cf8c3
    ------------------------------------------------------------
    revno: 3978.1.1
    revision-id: andrew.bennetts at canonical.com-20090203055031-q0rde12116uv20t7
    parent: pqm at pqm.ubuntu.com-20090202091414-4q20mjzsvp03vyfc
    committer: Andrew Bennetts <andrew.bennetts at canonical.com>
    branch nick: pdb-workaround
    timestamp: Tue 2009-02-03 16:50:31 +1100
    message:
      Add workaround for buggy pdb.post_mortem.
    modified:
      bzrlib/commands.py             bzr.py-20050309040720-d10f4714595cf8c3
=== modified file 'NEWS'
--- a/NEWS	2009-01-31 04:17:43 +0000
+++ b/NEWS	2009-02-04 04:19:15 +0000
@@ -62,6 +62,11 @@
     * Rule-based preferences can now accept multiple patterns for a set of
       rules.  (Marius Kruger)
 
+    * The debugger started as a result of setting ``$BZR_PDB`` works
+      around a bug in ``pdb``, http://bugs.python.org/issue4150.  The bug
+      can cause truncated tracebacks in Python versions before 2.6.
+      (Andrew Bennetts)
+
     * VirtualVersionedFiles now implements
       ``iter_lines_added_or_present_in_keys``. This allows the creation of 
       new branches based on stacked bzr-svn branches. (#311997)

=== modified file 'bzrlib/commands.py'
--- a/bzrlib/commands.py	2008-12-16 07:56:29 +0000
+++ b/bzrlib/commands.py	2009-02-04 04:10:14 +0000
@@ -894,11 +894,32 @@
     except (KeyboardInterrupt, Exception), e:
         # used to handle AssertionError and KeyboardInterrupt
         # specially here, but hopefully they're handled ok by the logger now
-        exitcode = trace.report_exception(sys.exc_info(), sys.stderr)
+        exc_info = sys.exc_info()
+        exitcode = trace.report_exception(exc_info, sys.stderr)
         if os.environ.get('BZR_PDB'):
             print '**** entering debugger'
+            tb = exc_info[2]
             import pdb
-            pdb.post_mortem(sys.exc_traceback)
+            if sys.version_info[:2] < (2, 6):
+                # XXX: we want to do
+                #    pdb.post_mortem(tb)
+                # but because pdb.post_mortem gives bad results for tracebacks
+                # from inside generators, we do it manually.
+                # (http://bugs.python.org/issue4150, fixed in Python 2.6)
+                
+                # Setup pdb on the traceback
+                p = pdb.Pdb()
+                p.reset()
+                p.setup(tb.tb_frame, tb)
+                # Point the debugger at the deepest frame of the stack
+                p.curindex = len(p.stack) - 1
+                p.curframe = p.stack[p.curindex]
+                # Start the pdb prompt.
+                p.print_stack_entry(p.stack[p.curindex])
+                p.execRcLines()
+                p.cmdloop()
+            else:
+                pdb.post_mortem(tb)
         return exitcode