fish-shell/share/tools
Bjorn Neergaard 02e9486559
Fix manpath handling in create_manpage_completions.py (#6879)
* Fix manpath handling in create_manpage_completions.py

...as well as do some (very!) light cleanup.

Currently, `create_manpage_completions.py` does not properly
understand/respect the `$MANPATH` variable. One important feature of
`$MANPATH` is that an empty component (i.e. the trailing : in
`foo:bar:`) expands to the 'default' or 'system' path -- that is to say,
the path that would be used if `$MANPATH` was unset. This allows the
user to extend the manpath without clobbering it, and has been a feature
many Unices have included for years.

The current implementation blindly uses the `$MANPATH` variable if it
exists, which does not allow for this behaviour -- to expand the
variable correctly, an external program must be invoked. Therefore, we
first shell out to the 'proper' (read: best guess) external program. If
that fails, we can then try to use `$MANPATH` directly/literally.
Finally, if both of those are impossible, we can fall back to some
common paths from widely used operating systems.

Note that the `man.conf` parsing has been removed: this is because while
many 'traditional' Unices (BSDs, Solaris, macOS) support this file, only
macOS actually ships a file -- most other Unices use a `conf.d`-style
layout and supporting that from our Python is impractical and silly at
best. On GNU (read: Linux) systems, `mandb` uses `/etc/man_db.conf` with
slightly different syntax and sematics. As this code-path has bitrotted
(and likely never worked, anyway), just remove it.

`create_manpage_completions.py` looks like it has suffered a lot of
confusion and bitrot in general over the last few years -- and is
overdue for a major refactoring. I am quite interested in tackling this,
but I plan to wait until the go-ahead to drop support for Python 2 is
given, as a major refactor/rewrite that still supports Python 2 (and
thus ignores the ergonomic/API/syntax improvements of Python 3) does not
make sense to me.

Related: #5657

It would probably be good to revisit `man.fish` once again when a
comprehensive refactor happens: hopefully every permutation of
`man`/`$MANPATH` could be documented as part of that effort.

* Restore /etc/man.conf parsing

I was not aware that this codepath was used -- since it appeared that it
would throw an error when it was reached. Redo it, using regex, and
support parsing NetBSD man.conf as well (untested).

* Fix create_manpage_completions.py under Python 2
2020-05-07 21:01:02 +02:00
..
web_config Restyle 2020-03-26 20:45:40 +01:00
create_manpage_completions.py Fix manpath handling in create_manpage_completions.py (#6879) 2020-05-07 21:01:02 +02:00
deroff.py Fix: equality vs identity 2019-11-06 14:13:21 +08:00