diff file type detected as man

[qouoq]

When viewing a diff with nvimpager, the file type detected is man. I see the behavior with 0.12.0 and with the main branch.

To try to make the test isolated, I proceed as follows:

• hg diff > test_diff (git diff gives the same results)
• nvimpager -- --clean test_diff :set filetype reports man
• nvim --clean test_diff :set filetype reports diff

Piping (hg diff | nvimpager -- --clean and hg diff | nvim --clean) gives the same results for both nvimpager and neovim.

I renamed ~/.config/nvimpager/init.vim to make sure it's not interfering, but the --clean option is sufficient to ignore it from what I see.

Other files (for example markdown and lua from their extension, a bash script from its shebang) have their filetype detected by nvimpager as expected.

-- edit: I was thinking that might be related to some changes related to man page detection in v0.12.0, and indeed, v0.11.0 detects diffs as expected.

[lucc]

I can reproduce this with some random diff so it should be possible to create a test case for this. I will look into it as soon as I find the time.

Others are welcome to jump at this issue if you want to help.

[lucc]

I assume the origin of the bug is 21453a92506eb7dd75fa40e4db3a3afdc665636d

[lucc]

It seems that during startup ( with nvimpager -p - < diff-file -c 'set ft' ) the filetype is still diff but later in the running nvim interface set ft returns man.

I have trouble writing a test case for this because I can not get the value from the running nvim process after it stated and opened the interface. Any ideas?

[qouoq]

Interestingly, the diff-file I create reports man, while test/fixtures/diff reports diff.

I don't know if that can be used in the test framework (at least non-invasively), but if I add in the main nvimpager bash script two commands in the args2 array, such as:

args2=(
  --cmd 'lua nvimpager.stage1()'
  -c 'lua nvimpager.stage2()'
  -c 'echo &filetype'
  -c 'qa'
)

Then I get:

$ ./nvimpager -c -- --clean diff-file         
man%
$ ./nvimpager -c -- --clean test/fixtures/diff
diff%

[lucc]

@qouoq thank you that was a good hint, I was able to construct a test case that fails (locally at last, CI is currently broken for other reasons).