[cfe-dev] GitHub Migration Schedule and Plans

[Martin Storsjö via cfe-dev]

On Thu, 10 Oct 2019, Tom Stellard via cfe-dev wrote:

> On 10/09/2019 11:05 PM, Mehdi AMINI wrote:
>> 
>> 
>> On Wed, Oct 9, 2019 at 10:16 PM Tom Stellard via cfe-dev <cfe-dev at lists.llvm.org <mailto:cfe-dev at lists.llvm.org>> wrote:
>>
>>     Hi,
>>
>>     We're less than 2 weeks away from the developer meeting, so I wanted to
>>     give an update on the GitHub migration and what's (hopefully) going to
>>     happen during the developer meeting.
>>
>>     Everyone who has added their information to the github-usernames.txt
>>     file in SVN before today should have received an invite to become a collaborator
>>     on the llvm-project repository.  If you did not receive an invite and think
>>     you should have, please contact me off-list.  I will continue to monitor the
>>     file for new updates and periodically send out new batches of invites.
>>
>>     There is still some ongoing work to get the buildbots ready and the mailing lists
>>     ready, but we are optimistic that the work will be done in time.
>>
>>     The team at GitHub has finished implementing the "Require Linear History"
>>     branch protection that we requested.  The feature is in beta and currently
>>     enabled in the llvm-project repository.  This means that we will have the
>>     option to commit directly via git, in addition to using the git-llvm script.
>>     A patch that updates git-llvm to push to git instead of svn can be found here:
>>     https://reviews.llvm.org/D67772.  You should be able to test it out on your
>>     own fork of the llvm-project repository.
>>
>>     The current plan is to begin the final migration steps on the evening (PDT)
>>     of October 21.  Here is what will happen:
>>
>>     1. Make SVN read-only.
>>     2. Turn-off the SVN->git update process.
>>     3. Commit the new git-llvm script directly to github.
>>     4. Grant all contributors write access to the repository.
>> 
>> 
>> Is the repo configured to forbid contributors to create new branches? I'm worried about the "jungle" it can become quickly if we leave open the possibility to create branches "at will" in the repo, I rather leave this to maintainers.
>> 
>
> I haven't been able to find a way to restrict branch creation for committers,
> I'm not sure if this is even possible.
>
> We could try to enforce this rule in the git-llvm script, but this would
> mean making use of the script mandatory, which was our original plan, but
> that was based on the assumption that the "Require Linear History"
> protection would not be ready in time.
>
> Generally, would it be better if we kept use of the script mandatory so that 
> we can handle this and other potential restrictions in the future?

Personally, I'd prefer to avoid requiring a custom tool for pushing 
commits, if possible.

As for creating undesired branches; contrary to accidentally pushing merge 
commits on the master branch, any accidentally created branch should be 
possible to remove without any permanent traces left behind (especially as 
it doesn't affect the master branch). So for that purpose alone, I'd vote 
for not requiring git-llvm for pushing.

Btw, out of curiousity, what mechanism does GitHub offer for verifying 
that the push actually comes from git-llvm? (I'm sorry if this part was 
discussed elsewhere, but I don't remember seeing it discussed lately.)

// Martin