compilation mode: wrong default error regexp blocking workflow

[LanX]

Hi

I have to minor problems which become pretty annoying in combination.


1. There is a default error-regex for some languages like perl and python which 
I can't alter or delete. 

Any sequence with colons 'NAME:NUMBER:' will not only be matched as errorline, 
but NAME grep anything from line's start, including hashes and whitespace(!)

just compile the following line in perl or python mode, and you'll see that '# 
file' is considered a filename.
  
  print "# file:15:"

I already checked compilation-error-regexp-alist and 
compilation-error-regexp-alist-alist but my perl settings do not include such a 
regex and I don't even have any setting for python.

This seems to be hardcoded somewhere.

2. Unfortunately I can't ignore those false matches cause activating 
compilation-auto-jump-to-first-error will automatically try to open this 
unexisting file and hang in the dialog, even pop up a file browser under X.

I couldn't find any option to disable next-error from trying this.

Now my questions:

1. How can I disable or change this default error-regex?
2. How can I tell next-error not to open unexisting files?

 emacs -version: GNU Emacs 23.3.1

Cheers
  LanX

PS: Crossposted similar stuff on stackoverflow without success so far:

see 
http://stackoverflow.com/questions/27463431/emacs-compilation-mode-marking-wrong-lines-as-errors