Re: Git commit generation numbers

On Fri, Jul 22, 2011 at 12:06:08PM -0700, Linus Torvalds wrote:

On Fri, Jul 22, 2011 at 11:34 AM, Jakub Narebski [off-list ref] wrote:

quoted

That is IF unknown headers are copied verbatim during rebase.  For
"encoding" header this is a good thing, for "generation" it isn't.

Afaik, they aren't copied verbatim, and never have been. Afaik, the
only thing that has *ever* written commits is "commit_tree()"
(originally "main()" in commit-tree.c). Why is this red herring even
being discussed?

In git.git, that is the case. There are other programs that may write
git commits, though. Try:

  http://www.google.com/codesearch#search/&q=hash-object.*commit&type=cs

Many uses seem OK (they are generating a commit from scratch). This one
at least (the sixth result from the search above) would actually
generate buggy generation headers (it modifies parents but passes other
headers through):

  http://www.google.com/codesearch#XUVcT9DKB_U/replace&ct=rc&cd=7&q=hash-object.*commit

It may be worth saying that such code is stupid and ugly and wrong, or
that it is not deployed widely enough to care about.  But it's not
entirely a red herring.

-Peff