Thread

1. pl/python tracebacks v2

   Jan Urbański <wulczer@wulczer.org> — 2011-03-20T23:40:02Z

   I finally got around to updating the PL/Python tracebacks patch. The
   other day I was writing some very simple PL/Python code and the lack of
   tracebacks is extremely annoying.
   
   Getting a TypeError without any line information in a function with 30
   lines because there's a %d instead of a %s somewhere in a logging call
   can make your debugging experience very lousy.
   
   Attached is a patch against master, with simplified error forming logic
   and the traceback in the context field. If you look at the expected
   regression test output, you will see that the only thing that changes is
   the presense of tracebacks in context messages.
   
   I'll update the commitfest app for the 2011-Next commitfest, but if
   someone would like to pick this up and include it in the 9.1 PL/Python
   revamp pack, I'd be thrilled.
   
   Cheers,
   Jan
   

2. Re: pl/python tracebacks v2

   Peter Geoghegan <peter@2ndquadrant.com> — 2011-03-21T01:47:18Z

   On 20 March 2011 23:40, Jan Urbański <wulczer@wulczer.org> wrote:
   > I'll update the commitfest app for the 2011-Next commitfest, but if
   > someone would like to pick this up and include it in the 9.1 PL/Python
   > revamp pack, I'd be thrilled.
   
   I would also be thrilled. I definitely share your sense of frustration
   about the lack of tracebacks available when writing pl/python.
   
   -- 
   Peter Geoghegan       http://www.2ndQuadrant.com/
   PostgreSQL Development, 24x7 Support, Training and Services
   
   

3. Re: pl/python tracebacks v2

   Peter Eisentraut <peter_e@gmx.net> — 2011-04-06T19:38:25Z

   On mån, 2011-03-21 at 00:40 +0100, Jan Urbański wrote:
   > I finally got around to updating the PL/Python tracebacks patch. The
   > other day I was writing some very simple PL/Python code and the lack of
   > tracebacks is extremely annoying.
   
   I tweaked this a bit to make the patch less invasive, and then committed
   it. :)
   
   
   

4. Re: pl/python tracebacks v2

   Jan Urbański <wulczer@wulczer.org> — 2011-04-06T20:16:13Z

   On 06/04/11 21:38, Peter Eisentraut wrote:
   > On mån, 2011-03-21 at 00:40 +0100, Jan Urbański wrote:
   >> I finally got around to updating the PL/Python tracebacks patch. The
   >> other day I was writing some very simple PL/Python code and the lack of
   >> tracebacks is extremely annoying.
   > 
   > I tweaked this a bit to make the patch less invasive, and then committed
   > it. :)
   
   Ouch, just today I found a flaw in this, namely that it assumes the
   lineno from the traceback always refers to the PL/Python function. If
   you create a PL/Python function that imports some code, runs it, and
   that code raises an exception, PLy_traceback will get utterly confused.
   
   Working on a fix...
   
   Jan
   
   PS: obviously it'd be great to have PL/Python traceback support in 9.1,
   but I sure hope we'll get some testing in beta for issues like this...
   
   J
   
   

5. Re: pl/python tracebacks v2

   Jan Urbański <wulczer@wulczer.org> — 2011-04-06T21:54:41Z

   On 06/04/11 22:16, Jan Urbański wrote:
   > On 06/04/11 21:38, Peter Eisentraut wrote:
   >> On mån, 2011-03-21 at 00:40 +0100, Jan Urbański wrote:
   >>> I finally got around to updating the PL/Python tracebacks patch. The
   >>> other day I was writing some very simple PL/Python code and the lack of
   >>> tracebacks is extremely annoying.
   >>
   >> I tweaked this a bit to make the patch less invasive, and then committed
   >> it. :)
   > 
   > Ouch, just today I found a flaw in this, namely that it assumes the
   > lineno from the traceback always refers to the PL/Python function. If
   > you create a PL/Python function that imports some code, runs it, and
   > that code raises an exception, PLy_traceback will get utterly confused.
   > 
   > Working on a fix...
   
   Here's the fix.
   
   The actual bug was funny. The traceback code was fetching the file line
   from the traceback and trying to get that line from the original source
   to print it. But sometimes that line was refering to a different source
   file, like when the exception originated from an imported module.
   
   In my testing I accidentally had the error (in a separate module) on
   line 2, so the traceback code tried to fetch line 2 of the function,
   which was completely whitespace. This can never happen in theory,
   because you can't have a frame starting at an all-whitespace line. The
   code to get that line was misbehaving and trying to do a malloc(-2),
   which in turn was causing an "ERROR invalid memory allocation".
   
   All that is fixed with the attached patch.
   
   Cheers,
   Jan
   
   PS: and thanks for committing that in the first place! :)
   
   J
   

6. Re: pl/python tracebacks v2

   Peter Eisentraut <peter_e@gmx.net> — 2011-04-20T20:22:33Z

   On Wed, 2011-04-06 at 23:54 +0200, Jan Urbański wrote:
   > > Ouch, just today I found a flaw in this, namely that it assumes the
   > > lineno from the traceback always refers to the PL/Python function. If
   > > you create a PL/Python function that imports some code, runs it, and
   > > that code raises an exception, PLy_traceback will get utterly confused.
   > > 
   > > Working on a fix...
   > 
   > Here's the fix.
   
   Committed.