My task at hand is to figure out, what is the commit id of the last commit, where a specific file changed. I'm using ruby / rugged. The only solution I came up with is to walk over all commits, search for the file in the tree associated with the commit for that file and compare that files oid with the oid of the file from the first (latest) commit:
def commit_oid commit, file
commit.tree.walk( :postorder ) { | root, obj |
return obj[ :oid ] if "#{root}#{obj[ :name ]}" == file
}
raise "\'#{file}\' not found in repository"
end
def find_last_commit file
johnny = Rugged::Walker.new( get_repository )
johnny.push get_repository.head.target
oid = commit_oid johnny.first, file
old_commit = johnny.first.oid
johnny.each do | commit |
new_oid = commit_oid commit, file
return old_commit if new_oid != oid
old_commit = commit.oid
end
old_commit
end
This works but seems to be quit complicated. There must be an easier ways to get the information, "what changed with a commit". Is there an easier, more straight forward way to accomplish the same?
Running $ git log <file> will give you a reverse chronological log of only commits that altered the given file. $ git whatchanged <file> will do the same, adding a line with details of the change (i.e. mode change, change type). It's great for visual purposes, but not so much for scripting.
If you want just the hash of the most recent commit, the following will work well: $ git rev-list --max-count 1 HEAD <file>