mandoc and perl/posix man pages

Presently, Alpine install Perl and POSIX man pages to /usr/share/man/man3 and /usr/share/man/man1. In order to distinguish them from Linux man pages with the same name, these pages have a custom file extension. For example:

/usr/share/man/man3/open.3pm.gz
/usr/share/man/man3/open.3p.gz

Where open.3pm.gz is the Perl man page and open.3p.gz is the POSIX man page. Unfortunately, this causes problems with mandoc. For example, it presently seems to be impossible to open the open(3p) man page (i.e. the POSIX man page for open) if perl-doc is installed:

$ man 3p open

Will always open the Perl man page which is not what one would expect as the invocation explicitly states that the open man page in the 3p section (i.e. Alpine's POSIX man page section) should be opened.

Looking at the mandoc source code, it seems that mandoc expects subdirectories to exist in MANDIR (i.e. /usr/share/man) for each man page section. From the fs_lookup function in main.c:

mandoc_asprintf(&file, "%s/man%s/%s.[01-9]*",
	paths->paths[ipath], sec, name);
globres = glob(file, 0, NULL, &globinfo);
if (globres != 0 && globres != GLOB_NOMATCH)
	warn("%s: glob", file);

As such, man 3p open would expect to find the open(3p) man page in /usr/share/man/man3p on Alpine. However, as illustrated above it is presently installed as /usr/share/man/man3/open.3p.gz and thus not found by mandoc.

I would propose moving all POSIX man pages to /usr/share/man/man3p, /usr/share/man/man1p, … and moving the Perl man pages to /usr/share/man/man3pm. The latter will likely require rebuilding all Perl packages which ship a doc subpackage.

On a side note, OpenBSD itself seems to use the 3p section for Perl man pages. For this reason the 0p, 1p, as well as the proposed 3pm section are not searched by default if no section is given [1]. However, this could be fixed with a trivial mandoc patch.