[BUG] man(7) page not showing footer

[Alejandro Colomar]

Hi Branden!

Another bug.  This time in troff(1) it seems.

This is weird.  I received a report about the page `core` [1].  I didn't even 
know from which section it was, so the first thing I do is:

```
$ whatis core
core (5)             - core dump file
CORE (3perl)         - Namespace for Perl's core routines
```

Okay, section 5, that little stranger to me.  Let's open the page, and see if 
it's from the Linux man-pages or not:

```
$ man core | tail -n1
       dump(8)
$ man core | tail -n4
SEE ALSO
       bash(1),   coredumpctl(1),  gdb(1),  getrlimit(2),  mmap(2),  prctl(2),
       sigaction(2), elf(5), proc(5),  pthreads(7),  signal(7),  systemd-core‐
       dump(8)
```

What?  There's no footer!  Which page am I seeing?

```
$ man -w core
/usr/local/man/man5/core.5
```

/usr/local, that means it's likely from the Linux man-pages.

```
alx@asus5775:~/src/linux/man-pages/man-pages$ man ./man5/core.5 | tail -n1
       dump(8)
```

After inspect$ tbl man5/core.5 | eqn -Tutf8  | /usr/bin/troff -man -ww -Tutf8 
-rLL=78n | grep unreleased
t(unreleased)
ion of the source code, there isn't anything weird that would change the footer. 
 Let's check the system page (from the 6.01-1 Debian Sid package).

```
$ man /usr/share/man/man5/core.5.gz | tail -n1
       dump(8)
```

Same thing.  Hmm.  Then I decided to make the terminal smaller to have a nice 
email, and surprise.  Now the terminal is 72 chars:

```
$ man ./man5/core.5 | tail -n1
Linux man‐pages (unreleased)    (date)                         core(5)
```

Since I know how the groff pipeline is working from the linting work on the 
man-pages makefile, I just run it manually.  I notice that exactly '-rLL=78n' 
doesn't show the footer, but higher or lower values (77 or 79) do show the footer.

```
$ tbl ./man5/core.5 \
  | eqn -Tutf8 \
  | troff -man -ww -Tutf8 -rLL=78n \
  | grep unreleased;
$ tbl ./man5/core.5 \
  | eqn -Tutf8 \
  | troff -man -ww -Tutf8 -rLL=77n \
  | grep unreleased;
t(unreleased)
$ tbl ./man5/core.5 \
  | eqn -Tutf8 \
  | troff -man -ww -Tutf8 -rLL=79n \
  | grep unreleased;
t(unreleased)
```

I don't understand those codes to be able to reason the bog, though.  That 
troff(1) is 1.23.0.

```
$ which -a troff
/usr/local/bin/troff
/usr/bin/troff
/bin/troff
$ troff --version
GNU troff (groff) version 1.23.0.rc1.2913-2756
$ /usr/bin/troff --version
GNU troff (groff) version 1.22.4
```

If I try to run with 1.22.4, I can't reproduce the bug:

```
$ tbl man5/core.5 \
  | eqn -Tutf8 \
  | /usr/bin/troff -man -ww -Tutf8 -rLL=78n \
  | grep unreleased;
t(unreleased)
```

And the same with other LL values.  I hope this helps to kill that bug :)

Cheers,

Alex


[1]: <https://bugzilla.kernel.org/show_bug.cgi?id=216648>
--
<http://www.alejandro-colomar.es/>

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