Re: [PATCH] add a reflog_exists and delete_reflog abstraction

[Michael Haggerty <mhagger@alum.mit.edu>]

On 05/06/2014 12:57 AM, Ronnie Sahlberg wrote:
> This is a single patch that adds two new functions to try to hide the reflog
> implementation details from the callers in checkout.c and reflog.c.
> It adds new functions to test if a reflog exists and to delete it, thus
> allowing checkout.c to perform this if-test-then-delete operation without
> having to know the internal implementation of reflogs (i.e. that they are files
> that live unde r.git/logs)
> 
> It also changes checkout.c to use ref_exists when checking for whether a ref
> exists or not instead of checking if the loose ref file exists or not.
> Using ref_exists instead both hides the reflog implementation details from
> checkout.c as well as making the code more robust against future changes.
> It currently has a hard assumption that the loose ref file must exist at this
> stage or else it would end up deleting the reflog which is true today, as far
> as I can tell, but would break if git would change such that we could have
> a branch checked out without having a loose ref file for that branch.

For single patches, people usually don't send a separate cover letter.
Any comments that you want to make that are not suitable for the commit
message can go between the "---" line and the diffstat of the patch email.

Regarding this change, I think before too long we will also need an API
to turn reflogs on for a reference.  We might want to add a flag to ref
transaction entries that cause the reflog to be created if it doesn't
already exist.  Reflogs can currently be created for a reference via the
config setting "core.logAllRefUpdates" or (for branches) by "git branch
--create-reflog" (maybe there are others).

Several tests in the test suite currently create reflog files by hand.
Thus we might also need a way to create reflogs at the command line by
the time we implement pluggable reference backends.

Michael

-- 
Michael Haggerty
mhagger@alum.mit.edu
http://softwareswirl.blogspot.com/