Re: [PATCH 3/3] Windows: teach getenv to do a case-sensitive search

[Karsten Blees <blees@dcon.de>]

Hmm...this looks like a pretty fragile solution to me. Wouldn't it be simpler
and safer to just fix the conflicting variables, instead of inventing entirely
new environment semantics for Windows?

I looked at the eval_gettext occurences, and only found '$path' in
git-submodule.sh to obviously conflict with existing environment variables. So
the straightforward solution IMO would be to fix the variable in that script.

Small solution (only affects gettext): in git-submodule.sh, replace all
'eval_gettext...$path' with 'modulepath=$path eval_gettext...$modulepath'

Big solution (enables git-submodule-foreach scripts on Windows, but is a
breaking change for existing foreach scripts on Unix): in git-submodule.sh,
t/t7407-submodule-foreach.sh, Documentation/git-submodule.txt, replace all
'$path' with '$modulepath' (also a few 'path=...' and 'while read...path')


Just a few failure scenarios that come to mind with the current solution:
- Given environment variables "Path" and "path", the 'case-sensitive first'
approach works fine for 'getenv("path")', but 'getenv("PATH")' still has a 50%
chance of failure.
- The other environment functions have not been changed to reflect the
'case-sensitive first' logic: setenv("path"...) and setenv("PATH"...) both have
a chance of overwriting the wrong entry, same for putenv.
- Windows applications generally don't support case-sensitive environment
variables, e.g. all MSYS and Cygwin programs convert environment variable names
to upper case on startup, eliminating duplicates in the process. With git.exe
beeing the only case-sensitive tool, any change to git-sh-i18n.sh (e.g.
replacing git-envsubst with a real gettext-envsubst) is likely to break again.
- As you already mentioned, Windows doesn't support case-sensitive environment
variable names, MSDN is pretty clear on that. Expressly violating this
documentation may cease to work with any new Windows version or patch.

Cheers,
Karsten