Issue with PAGER and MANPAGER

[dpo]

Hi. Thanks for a great plugin! I really enjoy all your tmux plugins!

I'm having an issue with Shift-K that I believe may be more due to Vim itself than to your plugin, but you'll probably be able to tell. I have overridden PAGER and MANPAGER in my ~/.bashrc (to use Vim actually) like so:

export PAGER=/Users/dpo/bin/Less.sh  # this basically just calls macros/less.vim
export MANPAGER="col -bx | view -c 'set ft=man nomod nolist' -c 'runtime! macros/less.vim' -"

If I hit Shift-K in my ~/.tmux.conf, I get the error

Vim: Warning: Output is not to a terminal
Vim: Warning: Input is not from a terminal
^M
?1000h?1049h?1h27m23mm94m100mH2J?25l24;1H"-stdin-" [readonly] 1763L, 101104C1;24r?12;25h?12l?25h27m23mm94m100mH2J?1000lVim:    Reading from stdin...
?1000h94m100m24;1H?1000lm94m100m39;49m?1l?12l?25h?1049lVim: Error reading input, exiting...
Vim: Reading from stdin...
Vim: Finished.
24;1H27m23mm94m100m39;49m

I believe this isn't related to your plugin because if I open any file in Vim, and execute

:runtime! ftplugin/man.vim
:Man tmux

I get the same error.

Now I see this bit in ftplugin/man.vim:

  if exists("$MANPAGER")
      let $MANPAGER = ""
  endif

The man page for man says that it first checks for MANPAGER, and if not set, it then checks for PAGER. So I added

  if exists("$PAGER")
      let $PAGER = ""
  endif

and all goes well. Is that an omission of man.vim? Or did I miss something in the configuration steps?

I'm using vim 7.4.712 on OSX.

Thanks in advance!

[bruno-]

Hey @dpo,
thanks for reporting. I must say I'm not very knowledgeable about this, but it seems you're right: man.vim shouldn't depend on user config where not necessary.

I suggest reporting this to man.vim maintainer. You can find his email in ftplugin/man.vim file header (I won't paste it here for spam reasons). I contacted the guy once and he was pretty responsive.

Let me know if you find anything new about this!

[dpo]

Thanks @bruno- ! A patch was sent to Bram Molenaar earlier today!

[bruno-]

Hey @dpo,
I was thinking about this problem and actually I'm not sure if setting the $PAGER to blank value is a good thing to do here. If that's done that affects all the programs executed from vim. This seems to have some nasty side effects. Here's the example:

• unset PAGER env var in vim with: :let $PAGER=''
• now running programs that require a pager results in an error. Examples: :!man bash and :!ri to_a (ri is a ruby docs browser)

Do you also get errors when executing the above steps?

If yes, I'm afraid this is not a theoretical issue. ri program is set as the default keywordprg for ruby files and I think man is vim's default (so many users in both cases). Could it happen all those users get an error if they hit <shift>k after they have loaded man.vim (and PAGER was set to empty string)?

[dpo]

@bruno- I'm afraid you're right. I also get an error message. Something is wrong because the manpage for man states that if neither MANPAGER nor PAGER are set, then man uses /usr/bin/less -is, so it's not clear to me why less isn't being invoked.

[dpo]

A possible solution would be for man.vim to always invoke man with -P to specify a particular pager and override MANPAGER and PAGER without unsetting them.

[bruno-]

That's a good idea but keep in mind -P flag for man might not be available on all the systems as it seems it's not defined in posix. Still, maybe that flag is omnipresent in man implementations, just not defined..