Re: Blaming diffs

[Mike Hommey <mh@glandium.org>]

On Sun, Sep 16, 2007 at 07:05:35PM +0200, Frank Lichtenheld <frank@lichtenheld.de> wrote:
> On Sun, Sep 16, 2007 at 06:38:29PM +0200, Mike Hommey wrote:
> > 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