dont mkdir any path that starts with '..' (instead of '../' previously)

[ordinary-slim]

Addresses #3224 . Tests (ran with make in tests folder) run.

[lervag]

Thanks, I appreciate the proposed fix. I'll probably accept it, but please consider my questions/comments in #3224 first.

[lervag]

Cool, as I can now reproduce this, I also understand it better. So, I don't think we should change the regex here. Instead, we should apply a simplify() on the dirs before we do the filter. That is, the following diff against your PR should be a more robust fix:

diff --git a/autoload/vimtex/compiler/_template.vim b/autoload/vimtex/compiler/_template.vim
index 7ec64c3b..28b5022c 100644
--- a/autoload/vimtex/compiler/_template.vim
+++ b/autoload/vimtex/compiler/_template.vim
@@ -125,7 +125,7 @@ function! s:compiler._create_build_dir(path) abort dict " {{{1
     call filter(map(
           \ l:dirs, "fnamemodify(v:val, ':h')"),
           \ {_, x -> x !=# '.'})
-    call filter(l:dirs, {_, x -> stridx(x, '..') != 0})
+    call filter(l:dirs, {_, x -> stridx(x, '../') != 0})
   else
     let l:dirs = glob(self.file_info.root . '/**/*.tex', v:false, v:true)
     call map(l:dirs, "fnamemodify(v:val, ':h')")
@@ -136,6 +136,7 @@ function! s:compiler._create_build_dir(path) abort dict " {{{1
   call map(l:dirs, {_, x ->
         \ (vimtex#paths#is_abs(a:path) ? '' : self.file_info.root . '/')
         \ . a:path . '/' . x})
+  call map(l:dirs, {_, x -> simplify(x) })
   call filter(l:dirs, '!isdirectory(v:val)')
   if empty(l:dirs) | return | endif

[ordinary-slim]

Your solution is more robust, thanks for letting me commit it.

[lervag]

No problem, and thanks again for your contribution! I'm always happy when people (like you) both detect a problem and attempt to fix it themselves, and I'm glad to assist and let you complete the final stages. :)