[New-bugs-announce] [issue9230] pdb.Pdb.checkline() throws AttributeError if called before starting a debug session

[Ivan Pozdeev]

New submission from Ivan Pozdeev <ivan_pozdeev at mail.ru>:

pdb.Pdb.checkline() throws AttributeError at pdb.py:470 if invoked before starting a debugging session because self.curframe doesn't exist at that time.

This breaks IPython's %run magic command (v0.10, Magic.py:1663). The command sets a breakpoint before running the script and scans the file before that to make sure the breakpoint is set on an executable line. 

This is a reasonable thing to do: setting a breakpoint and making sure it is set correctly shouldn't require a running debug session. So i conclude it is pdb, not IPython, that shall be fixed.

The patch attached gives linecache.getline() None as module_globals if self.curframe doesn't exist.

The rationale is: even if the script does use PEP302 import stuff, we can't know or use that before running it. So it's ok if we stay limited with usual paths.

----------
components: Library (Lib)
files: pdb_checkline.patch
keywords: patch
messages: 110065
nosy: __Vano
priority: normal
severity: normal
status: open
title: pdb.Pdb.checkline() throws AttributeError if called before starting a debug session
type: behavior
versions: Python 2.7
Added file: http://bugs.python.org/file17955/pdb_checkline.patch

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<http://bugs.python.org/issue9230>
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