----- "Jesse Keating" <jkeating(a)redhat.com> wrote:
I'm working on fixing a few long standing bugs in fedpkg that
have to
do
with our branch structure
(
https://bugzilla.redhat.com/show_bug.cgi?id=619979 and
https://bugzilla.redhat.com/show_bug.cgi?id=622592).
This has me examining our branch structure again and trying to
remember
why exactly I chose it (obviously I did a poor job of documenting
that...).
The original thought was to have top level branches that are named
after
distribution releases, eg "f14", "f15", "el5". Then we
would force
branches of those branches use a naming structure of "f14/topic".
The
reason was so that our tooling could look at the name of the branch
and
easily work back to the "f14" part. This would work even if it was
"f14/user/fred/topic/mybranch" or other such craziness. When I went
to
test this, I realized that git won't allow you to have both "f14" and
"f14/topic" as branches, because of the way the git metadata works on
the filesystem. When I encountered this, I made "f14/master" become
the
top level branch, and then "f14/somethingelse" could coexist.
Unfortunately I also wanted to keep things easy for users and tried
to
maintain tooling that would allow you to just say "f14". This didn't
get enough real world testing and in hindsight was a bad idea.
Things
go wrong quickly in git if your local branch name doesn't match the
remote branch name.
When thinking about the above, and the two bugs I'm working on, I
realized that we don't have any real strong need to be using "/" as a
delineator. It makes some code easier, but makes other things more
complex and difficult. So what if we changed it?
What I'm thinking about now is switching from / to - as a delineator.
This would improve a couple things. First, we could achieve upstream
top level branch names that are short and simple: "f14", "f15",
"master".
I'm all for this change. I believe the majority of users will
have an outcome with f14/f13-kind of branches.
We can have branches that build upon those names:
"f14-rebase", "f15-cve223", "f15-user-jkeating-private".
We could
keep
the simple fedpkg tooling that allows users to just type "f14" and
the
like to reference a branch, and now the local branch will match the
name
of the remote branch.
As for the first two bugs I mentioned, it doesn't directly help them.
However I would feel better about telling people that their local
branches must follow a naming scheme of <release>-<something> and
then
we could easily guess what release the local branch is for if it
isn't
tracking a remote branch. However the bug about what to do if there
are
no remote branches is really not touched by any of this, it just got
me
thinking about branches :)
What kind of user impact would this have?
My hope is that the impact would be minimal. Git allows branch
renames,
and can successfully rename "f14/master" to "f14". All the history
is
renamed. We should be able to do this without an outage of the git
server.
The ACL system will need a slight tweaking, and a regeneration of the
ACLs but that is fairly quick and minor to accomplish.
However there will be some issues client side. We will not be able
to
make use of git's symbolic-ref feature of "aliasing" a branch. We
cannot make "f14/master" an alias for "f14", again because of the
filesystem layout issues. These issues rear their head once again
when
a client does a pull of an already checked out repo that had
branches.
Because there was already a f14/master, when the client sees a new
branch just named "f14" it will fail to create it. Git has a command
that will fix this "git remote prune origin". That will remove the
local reference to f14/master and a subsequent pull sees the creation
of
the "f14" branch happen successfully. However, if a user had a local
branch of f14 or f14/master they will be left with mismatched
.git/config entries. In this case it's easiest to delete the local
branch (git branch -d f14) and check it out again. If there are
changes
on the branch one can fix the config to point it to the right
upstream
location.
Also we would need to get a new fedpkg into the hands of all the
developers that handles the new branchnames. We could do a build
that
handles both the oldnames and the new and have it out and available
for
a reasonable period of time before we make the switch.
Would it make sense to add functionality to fedpkg which checks if there
exists configuration for remote branch tracking (i.e. local "f14"
tracks remote "f14/master"), and if that's the case, print
a warning (e.g. that it's recommended to delete the local branch and
recreate/check it out again)? This won't help much for the "git pull"
problem, but it may prevent some users from running into that problem
in the first place, because they saw the warning earlier when switching
branch or doing some other fedpkg operation.
--Severin
So, some pain, for some pretty good gain. This time around I can
setup
pkgs.stg with this branch configuration and builds of fedpkg to use
it
for a more through testing before rolling it into production.
So please, tell me what you think!
--
Jesse Keating
Fedora -- FreedomĀ² is a feature!
identi.ca:
http://identi.ca/jkeating
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