Geografic-Information-System/doc/git/investigating_history.md

Investigating Code History

Plain git blame

In command line, to investigate commits which introduced a certain piece of code, you can use git blame:

git blame scripts/r.mask/r.mask.py

This will give you current content of the file with commit hash and author associated with each line.

Ignore some commits with git blame

Over the course of time, there was a lot of code reformatting changes which you typically want to ignore. These, often whitespace-only changes, can be filtered out using a ignore-revs file in the source code root directory:

git blame scripts/r.mask/r.mask.py --ignore-revs-file .git-blame-ignore-revs

In some cases, ignoring formatting changes may not be appropriate, for example when investigating automated checks of formatting. If you think the ignore-revs file contains commits which should be never ignored with git blame, please open an issue.

On GitHub

GitHub interface does not allow to use the ignore-revs file. However, it is easy to move over a revision by pressing "View blame prior to this change" which is the icon between commit info and line numbers.