GIT: ignoring changes in tracked files and bug report

Hi, I'm trying find a solution where I can change file in a devel environment , and not commit it into git .

git update-index --assume-unchanged <file> 

is one solution , not the best solution but one solution. 

I add 2 files that I want ignore on commits 

git update-index --assume-unchanged configurations/local.defs git update-index --assume-unchanged processor/default.defs

git diff -a is clean git diff . is clean

git commit -a nothing added to commit but git commit . # Changes to be committed: # modified: configurations/local.defs # modified: processor/default.defs

this is a bug ? 

Anyway what is best way to deal with some files where we want change locally and not commit in git . The solution of have one environment variable that says if we are in devel or in production , and system read the variable and choose the files to read can't be applied in my case, and is a no solution , is save a variable outside of source code which I can't.

Thanks,