git - Is there a way to have a patch that is never commited, only changes the working copy?

Question

I would like to modify a test to comment in some extra code:

-        /*SimpleMonitor monitor = new SimpleMonitor();
-        machine.attachMonitor(monitor);*/
+        SimpleMonitor monitor = new SimpleMonitor();
+        machine.attachMonitor(monitor);

That is, when I am building locally I would like to enable SimpleMonitor, but I always want the checked in code to keep it commented out. SimpleMonitor prints out some verbose information about what is going on internally in my test cases.

Of course I can just never add this change to the commit.

Is there a way with git that I can always exclude this change, even when using 'git add .' or 'git add -A' and so on, such that git will skip over this change?

The idea is that this is a delta that sits on top of a working copy only. If there is some neat trick with stash or using a branch or something else, do please tell me about it.

Answer 1

You could declare for your file a content filter driver ( a 'clean' script) which would automatically, on checkin, comment the right line.
That is done in a .gitattributes file: see for instance "Does .gitignore have an equivalent for version controlled files?".

^{(image from "Customizing Git Attributes" from the Git Book)}

git config filter.<filtername>.clean ./<filterscript>

You can have <filterscript> versioned in your repo.