Bug#272137: /usr/bin/dh_perl: dh_perl generates incorrectly named substvars files

[Anand Kumria <wildfire@progsoc.org>]

Package: debhelper
Version: 4.2.20
Severity: important
File: /usr/bin/dh_perl

[ lintian / linda author(s){1} may want to skip to ]
[ the rationale below and clone this bug report    ]

Hi,

I happened to be rebuilding libappconfig-perl; during the rebuild I
noticed this:

[...]
dh_perl
dh_gencontrol
dpkg-gencontrol: warning: unknown substitution variable ${perl:Depends}
dh_md5sums
[...]

A quick check reveals:
anand@eve:~/Debian/libappconfig-perl/AppConfig-1.56/debian$ cat substvars 
perl:Depends=perl (>= 5.6.0-16)

It is possible that this behaviour is occuring because of:
anand@eve:~/Debian/libappconfig-perl/AppConfig-1.56/debian$ cat compat 
4

since dh_gencontrol passes to dpkg-gencontrol:
  DB<1> 
main::(/usr/bin/dh_gencontrol:63):              doit(@command,
"-l$changelog", "-isp", "-Tdebian/${ext}substvars", 
  DB<1> x @command
0  'ommand'
  DB<2> x @command
0  'dpkg-gencontrol'
  DB<3> x ${ext}
0  'libappconfig-perl.'

and creating libappconfig-perl.substvars causes the error message to
disappear.

The rationale for 'important' by the way is that if that error message
is output (and ignored) it'll cause the deb to be created with no dependancy 
on perl.  (Actually no Depends: line at all - lintian and linda should 
both warn about that at least, if not error. Thus the CC).

anand@eve:~/Debian/libappconfig-perl/AppConfig-1.56$ dpkg-deb -I ../libappconfig-perl_1.56-1_all.deb | grep -i depend
anand@eve:~/Debian/libappconfig-perl/AppConfig-1.56$ lintian ../libappconfig-perl_1.56-1_all.deb 
anand@eve:~/Debian/libappconfig-perl/AppConfig-1.56$ linda ../libappconfig-perl_1.56-1_all.deb 
[...rebuild...]
You need a passphrase to unlock the secret key for
user: "Anand Kumria <wildfire@progsoc.org>"
1024-bit RSA key, ID FC05DA69, created 1997-05-12

                  
dpkg-buildpackage: full upload (original source is included)
anand@eve:~/Debian/libappconfig-perl/AppConfig-1.56$ dpkg-deb -I ../libappconfig-perl_1.56-1_all.deb | grep -i depend
 Depends: perl (>= 5.6.0-16)
anand@eve:~/Debian/libappconfig-perl/AppConfig-1.56$ lintian ../libappconfig-perl_1.56-1_all.deb 
anand@eve:~/Debian/libappconfig-perl/AppConfig-1.56$ linda ../libappconfig-perl_1.56-1_all.deb 

Something which neither lintian, nor linda, picked up. Which means
unless you tend to check manually (I bet quite a few developers don't)
you wouldn't pick up this problem.

Cheers,
Anand

{1}: See a perfectly valid English expression is what author(s) is.
Having lintian complain about valid English is annoying.

-- System Information:
Debian Release: 3.1
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: i386 (i686)
Kernel: Linux 2.6.7
Locale: LANG=C, LC_CTYPE=C

Versions of packages debhelper depends on:
ii  binutils                   2.14.90.0.7-8 The GNU assembler, linker and bina
ii  coreutils [fileutils]      5.2.1-2       The GNU core utilities
ii  debconf-utils              1.4.30.3      debconf utilities
ii  dpkg-dev                   1.10.23       Package building tools for Debian
ii  file                       4.09-1        Determines file type using "magic"
ii  fileutils                  5.2.1-2       The GNU file management utilities 
ii  html2text                  1.3.2a-1      An advanced HTML to text converter
ii  perl                       5.8.4-2       Larry Wall's Practical Extraction 
ii  po-debconf                 0.8.12        Manage translated Debconf template

-- no debconf information