Problem:
If vim_tempdir mysteriously goes missing (typically by "antivirus" on
Windows), any plugins using tempname() will be broken for the rest of
the session. #1432#9833https://groups.google.com/g/vim_use/c/ef55jNm5czI
Steps:
mkdir foo
TMPDIR=./foo nvim
:echo tempname()
!rm -r foo
:echo tempname()
tempname() still uses the foo path even though it was deleted.
Solution:
- Don't assume that vim_tempdir exists.
- If it goes missing once, retry vim_mktempdir and log (silently) an error.
- If it goes missing again, retry vim_mktempdir and show an error.
Rejected in Vim for performance reasons:
https://groups.google.com/g/vim_use/c/qgRob9SWDv8/m/FAOFVVcDTv0Jhttps://groups.google.com/g/vim_dev/c/cogp-Vye4oo/m/d_SVFXBbnnoJ
But, logging shows that `vim_gettempdir` is not called frequently.
Fixes#1432Fixes#9833Fixes#11250
Related: stdpath("run") f50135a32e
ce0fddf5ae