Re: git-mv redux: there must be something else going on

> On Wed, 3 Feb 2010, Ron Garret wrote:
> 
> > So... how *does* git decide when two blobs are different blobs and when 
> > they are the same blob with mods?  I asked this question before and was 
> > pointed to the diffcore docs, but that didn't really clear things up.  
> > That just describes all the different ways git can do diffs, not the 
> > actual heuristics that git uses to track content.
> 
> Yes, those same heuristics are used to make the decision.
> 
> |The second transformation in the chain is diffcore-break, and is
> |controlled by the -B option to the 'git diff-{asterisk}' commands.  
> |This is used to detect a filepair that represents "complete rewrite" 
> |and break such filepair into two filepairs that represent delete and
> |create.
> |[...]
> 
> |This transformation is used to detect renames and copies, and is
> |controlled by the -M option (to detect renames) and the -C option
> |(to detect copies as well) to the 'git diff-{asterisk}' commands.  
> |[...]
> 
> Note that you may use the -B, -C, -M and --find-copies-harder arguments 
> with log as well as diff commands even if there is no actual diff 
> output.  So the explanation is really in that document even if simple 
> rename detection is concerned only by a fraction of what is said there.
> 
> And Git can detect copied files too.
> 
> Those semantics are not stored in the repository so they can be improved 
> or even changed after the facts.