Bug? ignored files overwritten by checkout

Bug? ignored files overwritten by checkout

[Damien Robert]

git init
git commit --allow-empty -m "init"
git checkout -b test
echo foo > foo
git add foo
git commit -am 'add foo'
git checkout master
echo 'Important data' > foo #[1]
echo foo > .gitignore
git checkout test

If I tried a `git checkout test` after [1], I would get the error message 
    error: The following untracked working tree files would be overwritten by checkout: foo
But after adding foo to .gitignore, I am able to checkout to branch test
without warning. Of course this overwrites foo to the version in test.

I tested this in version 1.8.3.4 and 1.7.10.4.

Re: Bug? ignored files overwritten by checkout

[Jeff King]

On Thu, Aug 15, 2013 at 06:33:11AM +0000, Damien Robert wrote:

> git init
> git commit --allow-empty -m "init"
> git checkout -b test
> echo foo > foo
> git add foo
> git commit -am 'add foo'
> git checkout master
> echo 'Important data' > foo #[1]
> echo foo > .gitignore
> git checkout test
> 
> If I tried a `git checkout test` after [1], I would get the error message 
>     error: The following untracked working tree files would be overwritten by checkout: foo
> But after adding foo to .gitignore, I am able to checkout to branch test
> without warning. Of course this overwrites foo to the version in test.

This is by design. Marking a file in .gitignore tells git that the
content is not precious and can be removed if need be. For most ignored
files, this is what you want (e.g., you mark "*.o" as ignored because it
is generated; you do not want to add it, and you can always make it
again).

The less common case is a file that is precious and needs to live inside
your repository directory, but which you do not want to add (e.g., a
config file that affects your project, but should not ever be
committed).  People have occasionally asked for a .gitignore-like
mechanism to mark such files as "precious but do not add".  However,
nobody has actually implemented anything.

-Peff