.gitignore does not ignore Makefile

I have the following .gitignore file in patch arm/arm64/boot/dts:

*.dtb qcom qcom.orig

When I do a git status, I see this:

    modified:   .gitignore
    modified:   qcom/Makefile

All of the other files in arm/arm64/boot/dts/qcom are being ignored, as request. However, the file "Makefile" is not being ignored. Why? What's so special about "Makefile" that git refuses to ignore it?

On Thu, Sep 22, 2016 at 09:19:22AM -0500, Timur Tabi wrote:

There is nothing special about the Makefile, except that it's tracked. Git never ignores tracked files (almost a paradox).

You can untrack the file by doing git rm --cached <file>, which new commits won't have this file.

If your goal is to ignore local changes to a tracked file, then the advise is to reconsider your plan.

Often people advise tricks like `git update-index --assume-unchanges <file>`, but this does not work as expected. It's merely a promise to git that this file does not change (and hence, git will not check if this file has changed when doing git status), but command that try to change this file will abort saying that the file has changed.

Hope this helps,

Kevin.

Kevin Daudt <me@ikke.info> writes:

It actually is even worse. As the user promised Git that the <file> will not be modified and will be kept the same as the version in the index, Git reserves the right to _overwrite_ it with the version in the index anytime when it is convenient to do so, removing whatever local change the user had despite the promise to Git. The "abort saying that the file has changed" is merely various codepaths in the current implementation trying to be extra nice.

Junio C Hamano wrote:

So .gitignore only ignores new files, not modified ones? That seems odd, but I guess that's the way it's always been and I just haven't noticed until now.

Timur Tabi <timur@codeaurora.org> writes:

It is determines if an untracked file should be considered by "git add" to add it or ignore it.

W dniu 22.09.2016 o 20:26, Junio C Hamano napisał:

 
There is a trick that works almost as 'ignore changes' for tracked
files, namely `git update-index --skip-worktree <file>`.  From the
documentation:

  Skip-worktree bit
  ~~~~~~~~~~~~~~~~~

  Skip-worktree bit can be defined in one (long) sentence: When
  reading an entry, if it is marked as skip-worktree, then Git
  pretends its working directory version is up to date and read
  the index version instead.

  [...] Writing is not affected by this bit, content safety is still
  first priority. [...]

It works quite well; the only problem is that `git stash` would not stash away your changes, and you would need to unmark such file before saving a stash.

With --assume-unchanged used for ignoring changes to tracked files, you can quite easily lose your work because you are lying to Git.

Note also that in Git classic "ignored" implies unimportant.