Re: Blaming diffs

On Sun, Sep 16, 2007 at 07:05:35PM +0200, Frank Lichtenheld [off-list ref] wrote:

On Sun, Sep 16, 2007 at 06:38:29PM +0200, Mike Hommey wrote:

quoted

It seems to me there is no tool to "blame diffs", i.e. something to know
what commit(s) is(are) responsible for a set of changes.

For example, the following script tries to get the set of commits
involved in the changes between $A and $B. Note it only works for text
additions. 

git diff --unified=0 $A $B | awk 'BEGIN { FS="(^(--- a/|+++ b/)|^@@ -[0-9,]+ \\+| @@)" } /^---/ || ( /^+++ b\/(.*)/ && file=="" ) { file = $2 } /^@@/ {split($2, a, /,/); a[2] = a[2] ? a[2] + a[1] - 1 : a[1]; print "git blame -l -L " a[1] "," a[2], "'$A..$B'", file }' | sh | cut -f 1 -d " " | sort -u

Has anyone tried to work on something similar yet ?

If not, as git users, what kind of output would you expect from such a
tool, and where do you think this should lie (extension to git diff, or
separate tool) ?

What do you use for $A and $B? commits? What is the difference between
your script and "git log --pretty=format:%H $A..$B"
then?

In my typical usecase, $A is upstream and $B is HEAD. What happens is
that my work branch includes some changes that have been merged upstream
and some others that are not yet, or won't because it's not appropriate.
I obviously occasionally merge the upstream branch back, in which case
my changes that were committed upstream don't appear in a git diff $A $B
anymore.

git log --pretty=format:%H $A..$B would give me the list of all commits
that occurred on my branch, while my script only gives the commits
containing changes that are still not applied upstream.

Mike