Changing class name causes process to 'hang'

[Terry Reedy]

On 3/12/2011 7:18 PM, Tim Johnson wrote:
> * Terry Reedy<tjreedy at udel.edu>  [110312 13:28]:
>> On 3/12/2011 2:53 PM, Tim Johnson wrote:
>>
>> Is 'cgilib' *your* wrapper of the cgi module, or from a third party.

>    cgilib is my module. I use the cgi module as follows:
> ## code below
>      import cgi
>      self.form = cgi.FieldStorage(keep_blank_values=1)
> ## /code

And cgitools is a class therein?

>> Without seeing cgitools/cgirev, it is hard to say. Something like
>>
>> while True:
>>    try:
>>      x = cgitools()
>>      break
>>    except NameError
>>      pass
>>
>> would produce the symptom ;-)

>    Hmm! I'm unsure what you mean here, but

If the name 'cgitools' is used *somewhere*, not necessary in cgilib 
itself, other than in the class header itself, but the resulting 
NameError is *somehow* caught inside a retry loop, then your total 
application would exhibit the symptom you describe ('hanging'). This 
could happen if there is a bare 'except:' statement (these are not 
recommended) that needs to be specific 'except SomeError:'.

>    I did do something like this:
> ## code below
> if __name__=="__main__":
>      import sys,traceback
>      sys.stderr = sys.stdout ##
>      try :
>          print("Content-type: text/html\n")
>          print("<pre>")
>          cgi = CGI()
>          print("here")
>          print("CGI OUTPUT TEST")
>          for i in range(cgi.len_path_parts()):
>              print("path part # %d requested: %s" % (i,str(cgi[i])))
>      except :
>          traceback.print_exc()
> ## /code
> And I get
> CGI OUTPUT TEST
> path part # 0 requested: test
> path part # 1 requested: this
> Whether I use CGI or cgitools as the class name.
>
> But, if I use CGI as the class name and instantiate from a large application
> with numerous dependecies, the process hangs.

> The same happens if I 'alias' cgitools, as in
> class CGI(cgitools):
>      pass

You mean you leave 'class cgitools()...' alone within cgilib and just 
add that? That would discredit the theory above. What if you use a 
different alias, like 'moretools'? Are you on an OS where 'cgi' and 
'CGI' could get confused?

> It is as if some gremlin lives on my system and insists that I use
> the name `cgitools' and only the name `cgitools'. I'm sure
> this comes from a side effect somewhere in the process.
> thanks for the reply


-- 
Terry Jan Reedy