In the first line of a git commit message I have a habit of mentioning the file that modified if a change doesn't span multiple files, for example:

Add [somefunc] to [somefile] 


Is this a good thing to do or is it unnecessary?

Version control tools are powerful enough to let the person see what files were modified, and what methods were added. It means that in general, log messages which plainly duplicate what already exists are polluting the log.

You added somefunc method to fulfill a requirement, i.e.:


to add a feature,
to remove a bug or
to refactor the source code.


This means that your log messages must rather explain what features/bugs were affected or what was the purpose of the refactoring.
