Re: [PATCH v4] Allow update hooks to update refs on their own.

Hi,

On Mon, 3 Dec 2007, Shawn O. Pearce wrote:

Johannes Schindelin [off-list ref] wrote:

quoted

On Sun, 2 Dec 2007, Shawn O. Pearce wrote:

quoted

Steven Grimm [off-list ref] wrote:

quoted

This is useful in cases where a hook needs to modify an incoming commit
in some way, e.g., fixing whitespace errors, adding an annotation to
the commit message, noting the location of output from a profiling tool,
or committing to an svn repository using git-svn.

...

quoted

+/* Update hook exit code: hook has updated ref on its own */
+#define EXIT_CODE_REF_UPDATED 100

Hmm.  I would actually rather move the ref locking to before we run
the update hook, so the ref is locked *while* the hook executes.

Would that not mean that you cannot use update-ref to update the ref, 
since that wants to use the same lock?

You failed to quote the part of my email where I talked about how
we set an evironment variable to pass a hint to lockfile.c running
within the git-update-ref subprocess to instruct it to perform a
different style of locking, one that would work as a "recursive"
lock.

Such a recursive lock could be useful for a whole lot more than just
the update hook.  But it would at least allow the update hook to
use git-update-ref to safely change the ref, without receive-pack
losing its own lock on the ref.

Indeed, I even failed to read it fully ;-)

What do you propose, though?  <filename>.lock.<n>?

Ciao,
Dscho