Bug#745877: lintian: Unreasonable performance of detect_privacy_breach for clhep-doc/2.1.3.1-1/all

[Niels Thykier <niels@thykier.net>]

Package: lintian
Version: 2.5.22.1
Severity: important

Hi,

Philipp Kern noticed that lintian was really slow to process
clhep-doc.

I had a look at profiling it and, unsurprisingly, we are dealing with a
case similar to the cruft/license checks.  Profile was done with:

 perl -d:NYTProf frontend/lintian -C files clhep-doc_2.1.3.1-1_all.deb

(Interesting parts of the) Results:

"""
Profile of ../lintian/frontend/lintian for 227s (of 228s),
executing 2419803 statements and 1163869 subroutine calls in 171
source files and 36 string evals

[... line 1778 of checks/files.pm (sub detect_privacy_breach) ... ]

141096	186s	282192	185s	if ($block =~ m{$regex}) {

[... line 1792+1793 of checks/files.pm (sub detect_privacy_breach) ... ]
			      EXTERNAL_TAG:
17637	26.7s	17637	26.6s	while(
<... followed by ~40 lines of regex ...>
"""

Bastien, can you have a look at this one?

~Niels