[jira] Commented: (MODPYTHON-46) PythonHandlerModule directive is broken.

["Graham Dumpleton (JIRA)" <ji...@apache.org>]

    [ http://issues.apache.org/jira/browse/MODPYTHON-46?page=comments#action_12315281 ] 

Graham Dumpleton commented on MODPYTHON-46:
-------------------------------------------

Even when one works around this. There seems to be a bug deep
in the C code somewhere, whereby on occasion a request gets
stuck in an infinite loop when processing the PythonHandlerModule
directive. The stack trace is:

  directive_PythonHandlerModule
  python_directive_handler
  python_directive_hl_add
  hlist_append

Ie., gets stuck in a loop in hlist_append.

This comment is here just so I don't forget about it as not going to try and
track it down right now.

> PythonHandlerModule directive is broken.
> ----------------------------------------
>
>          Key: MODPYTHON-46
>          URL: http://issues.apache.org/jira/browse/MODPYTHON-46
>      Project: mod_python
>         Type: Bug
>   Components: core
>     Versions: 3.1.4
>     Reporter: Graham Dumpleton

>
> Documentation for PythonHandlerModule says:
>   PythonHandlerModule can be used an alternative to Python*Handler directives.
>   The module specified in this handler will be searched for existence of functions
>   matching the default handler function names, and if a function is found, it will
>   be executed.
> The suggestion is that it will not complain if a particular handler is defined, ie.,
> only executes the ones it finds and doesn't worry about the rest. The example
> even supports this by saying that:
>   For example, instead of:
>     PythonAutenHandler mymodule
>     PythonHandler mymodule
>     PythonLogHandler mymodule
>   one can simply say
>     PythonHandlerModule mymodule
> BTW, "PythonAutenHandler" is spelt wrong in documentation, not by me.
> The "mod_python.c" code also seems be coded so that if a handler is defined
> in the module that it will not complain.
>     python_directive_handler(cmd, mconfig, "PythonPostReadRequestHandler", val, SILENT);
>     python_directive_handler(cmd, mconfig, "PythonTransHandler", val, SILENT);
>     python_directive_handler(cmd, mconfig, "PythonHeaderParserHandler", val, SILENT);
>     python_directive_handler(cmd, mconfig, "PythonAccessHandler", val, SILENT);
>     python_directive_handler(cmd, mconfig, "PythonAuthzHandler", val, SILENT);
>     python_directive_handler(cmd, mconfig, "PythonTypeHandler", val, SILENT);
>     python_directive_handler(cmd, mconfig, "PythonHandler", val, SILENT);
>     python_directive_handler(cmd, mconfig, "PythonInitHandler", val, SILENT);
>     python_directive_handler(cmd, mconfig, "PythonLogHandler", val, SILENT);
>     python_directive_handler(cmd, mconfig, "PythonCleanupHandler", val, SILENT);
>     python_directive_handler(cmd, srv_conf, "PythonConnectionHandler", val, SILENT);
> Ie., it has "SILENT" option and not "NOTSILENT" as is case when single handler is
> specified.
> Problem is that using "PythonHandlerModule" it gives back 500 error and if
> "PythonDebug" is on you will see in the browser:
>   Mod_python error: "PythonHeaderParserHandler mptest"
>   Traceback (most recent call last):
>     File "/usr/lib/python2.3/site-packages/mod_python/apache.py", line 291, in HandlerDispatch
>       arg=req, silent=hlist.silent)
>     File "/usr/lib/python2.3/site-packages/mod_python/apache.py", line 519, in resolve_object
>       raise AttributeError, s
>   AttributeError: module '/home/grahamd/public_html/phases/mptest.py' contains no 'headerparserhandler'
> The passing of "SILENT" thus seems to not work.
> The definitions of SILENT and NOTSILENT are:
>   #define SILENT 0
>   #define NOTSILENT 1
> This eventually gets set as hlist.silent and gets passed as "silent" argument of
> the "resolve_object()" method.
> In the resolve_object() call of apache.py where this is checked, it is checked as:
>         # don't throw attribute errors when silent
>         if silent and not hasattr(obj, obj_str):
>             return None
>         # this adds a little clarity if we have an attriute error
>         if obj == module and not hasattr(module, obj_str):
>             if hasattr(module, "__file__"):
>                 s = "module '%s' contains no '%s'" % (module.__file__, obj_str)
>                 raise AttributeError, s
> Is the logic the wrong way around here or am I just going nuts?
> The result of "resolve_object()" is used as:
>                 if object:
>                     ...
>                 elif hlist.silent:
>                     result = DECLINED
> This is supposed to propogate ignoring of the fact that the handler is missing,
> but again logic is wrong way.
> The simple solution may be:
>   #define NOTSILENT 0
>   #define SILENT 1
> All uses of this silent flag needs to be reviewed though to determine if this is
> going to stuff up other areas of the code.

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