How does the findfile() function work?

Question

I don't understand the findfile() function in Vim-Script, what am i doing wrong?

set encoding = utf-8
cd %:p:h
let b:gitiginorfiles = findfile('.gitignore', system('git rev-parse --show-toplevel'), -1)

My variable b:gitignorefiles is always empty.

Answer 1

I need to chomp the trailing newline to see the line work:

:echo findfile('.gitignore', system('git rev-parse --show-toplevel')[:-2], -1)

This is a recurring problem with system(). I did rapidly end-up with a first version of system() in my library plugin that always chomps these unwanted characters.

EDIT: Otherwise, don't hesitate to extract intermediary result into variables that you'll be able to investigate. Often, I check what I really compute with a :echo .'##'.myvar.'##'.

Answer 2

Vim documentation is the best point to start. :help findfile():

findfile({name}[, {path}[, {count}]])               *findfile()*
        Just like |finddir()|, but find a file instead of a directory.
        Uses 'suffixesadd'.
        Example: >
            :echo findfile("tags.vim", ".;")
        Searches from the directory of the current file upwards until
        it finds the file "tags.vim".

You can use Ctrl+] to navigate into links, such as |finddir()|:

finddir({name}[, {path}[, {count}]])                *finddir()*
        Find directory {name} in {path}.  Supports both downwards and
        upwards recursive directory searches.  See |file-searching|
        for the syntax of {path}.
        Returns the path of the first found match.  When the found
        directory is below the current directory a relative path is
        returned.  Otherwise a full path is returned.
        (...)

You can debug that call using this:

:echo findfile('.gitignore', system('git rev-parse --show-toplevel'), -1)

This will run the findfile() and echo the result in the screen. You can use q: to edit the call and test again.

---

Edit

You could try to understand it better by using simple examples. For instance, try to search for a nonexistent file in the current direct, then create the file and repeat:

echo findfile('bla', .)   " empty result, no file
!touch bla                " create the file (this works in *nix systems)
echo findfile('bla', ".") " now it returns a non-empty result

You can check that you are in the directory you expect by using :pwd and getcwd().