Stop searching in further dirs on errors except ENOENT

[blueyed]

Taking over mauke#41.

[justinmk]

• included the description from Stop searching in further dirs on errors except ENOENT mauke/unibilium#41 in the commit message
• included reference to Stop searching in further dirs on errors except ENOENT mauke/unibilium#41 in the commit message

[blueyed]

@justinmk
I wanted to check how this behaves with regard to compatibility with ncurses, and also add tests..

[blueyed]

infocmp (from ncurses) at least behaves differently:

% cp /usr/share/terminfo/s/screen t/fixtures/invalid/s/screen
% TERMINFO=$PWD/t/fixtures/invalid infocmp screen
#	Reconstructed via infocmp from file: …/Vcs/unibilium/t/fixtures/invalid/s/screen
…
% echo invalid > $PWD/t/fixtures/invalid/s/screen
% TERMINFO=$PWD/t/fixtures/invalid infocmp screen
#	Reconstructed via infocmp from file: /usr/share/terminfo/s/screen
…

[blueyed]

However this patch does not change the behavior with "TERMINFO", which appears to be a bit inconsistent also then.

[pschyska]

This led to my vim silently failing on a TERMINFO_DIRS which was present, but not a directory; ~/.local/share/flatpak/exports was a file, no idea how this happened ¯\(ツ)/¯.
Neovim's &term fell back to builtin_ansi without indication, and the usual debugging steps - $TERM, infocmp, etc. did all report using terminfo/a/alacritty in that case. In neovim, I lost the ability to set title and render italics.
I'd rather keep searching here, and return the first (non-ENOENT, falling back to ENOENT) error if the search didn't ultimately succeed. This would keep the error behavior but not stop early.

[justinmk]

@pschyska feel like sending a PR to explore that idea?

[pschyska]

Maybe, but no promises as I've never used C 🙂