Bug#1040975: perl: pod2man uses CW, groff-base no longer supports this by default

[Andrew Ruthven]

Package: perl
Version: 5.36.0-7
Severity: normal

Dear Maintainer,

groff-base v1.23 has been uploaded to unstable, which disables the CW macro
by default. This causes errors like this to be generated with pod2man now:

puck@dirk:~$ pod2man /usr/share/perl/5.36.0/version.pod | nroff -man | grep CW
troff:<standard input>:145: warning: cannot select font 'CW'
troff:<standard input>:182: warning: cannot select font 'CW'
troff:<standard input>:191: warning: cannot select font 'CW'
troff:<standard input>:205: warning: cannot select font 'CW'
troff:<standard input>:207: warning: cannot select font 'CW'
...

This is causing lintian to be upset when build packages, e.g.:

W: rt-extension-mergeusers-common: groff-message troff:<standard input>:115: warning: cannot select font 'CW' [usr/share/man/man3/RT::Extension::MergeUsers.3pm.gz:1]

This version of groff-base introduces a new option in /etc/groff/man.local:

.\" "CW" is not a portable font name, but some man pages use it anyway.
.\" Uncomment this to suppress warnings produced by such pages. This
.\" test remaps the font to roman ("R") on nroff (terminal) devices. You
.\" might prefer to remap it to bold ("B") instead.
.\" .if n .ftr CW R

Now, is it pod2man or groff-base that is at fault here? Perl 5.38 still uses
CW in pod2man by default.

Cheers,
Andrew

-- System Information:
Debian Release: trixie/sid
APT prefers unstable
APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 6.0.0-6-amd64 (SMP w/8 CPU threads; PREEMPT)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=en_NZ.UTF-8, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages perl depends on:
ii dpkg 1.21.22
ii libperl5.36 5.36.0-7
ii perl-base 5.36.0-7
ii perl-modules-5.36 5.36.0-7

Versions of packages perl recommends:
ii netbase 6.4

Versions of packages perl suggests:
pn libtap-harness-archive-perl <none>
ii libterm-readline-gnu-perl 1.45-1
ii libterm-readline-perl-perl 1.0303-2.1
ii make 4.3-4.1
ii perl-doc 5.36.0-7

-- no debconf information

[Andrew Ruthven]

Control: reassign -1 groff-base
Control: affects -1 perl

Hey,

I think a change in groff-base to re-enable the CW font alias might be
reasonable. This affects a number of other packages, not just perl (via
pod2man), for example:

puck@dirk:~$ man --warnings /usr/share/man/man1/strace.1.gz > /dev/null
troff:<standard input>:88: warning: macro 'IX' not defined
troff:<standard input>:119: warning: cannot select font 'CW'

troff:<standard input>:124: warning: cannot select font 'CW'

...

(Lintian excludes the IX macro which is why that is present)

Cheers,
Andrew

--
Andrew Ruthven, Wellington, New Zealand
and...@etc.gen.nz |
Catalyst Cloud: | This space intentionally left blank
https://catalystcloud.nz |

[Colin Watson]

Control: clone -1 -2
Control: reassign -2 perl

On Fri, Jul 14, 2023 at 03:15:47PM +1200, Andrew Ruthven wrote:
> I think a change in groff-base to re-enable the CW font alias might be
> reasonable. This affects a number of other packages, not just perl (via
> pod2man), for example:
>
> puck@dirk:~$ man --warnings /usr/share/man/man1/strace.1.gz > /dev/null
> troff:<standard input>:88: warning: macro 'IX' not defined
> troff:<standard input>:119: warning: cannot select font 'CW'
> troff:<standard input>:124: warning: cannot select font 'CW'
> ...
>
> (Lintian excludes the IX macro which is why that is present)

I'll re-enable the CW alias, but I think pod2man should probably be
changed as well, since it'll still be generating pages that result in
warnings from upstream groff.

I'm less sure exactly what the change should be. Using CW does have its
advantages despite the non-portability: as I recall, it looks better in
troff output. Perhaps the generated document should attempt to use the
CW font if it exists, but otherwise suppress warnings and fall back to
R?

--
Colin Watson (he/him) [cjwa...@debian.org]