[llvm-dev] RFC: Switching from Bugzilla to Github Issues [UPDATED]

Tom Stellard via llvm-dev llvm-dev at lists.llvm.org
Wed Apr 29 08:24:48 PDT 2020


Thanks to everyone who provided feedback.  I would like to propose a
more detailed plan based on the everyone's comments.  It seems like there was a strong
preference to maintain the bug ID numbers, so this proposal tries to address that.

TLDR; This proposes to maintain bug ID numbers by overwriting existing GitHub issues
instead of creating new ones.  e.g. github.com/llvm/llvm-project/issues/1 will
be overwritten with data from llvm.org/PR1.  There will be some bugs that
end up having their data copied into pull requests, which may be strange,
but the data will be preserved and the IDs will be preserved and this would
only happen to very old bugs.


Detailed steps for doing the migration:

* Weeks or days before the migration:

1. Create a new GitHub repository called llvm-bug-archive and import bug
data from bugzilla.

This step should not be under any kind of time pressure, so that the conversion
process can be debugged and refined.

2. Install label notification system using GitHub actions and enable web hook
to send emails to llvm-bugs list.

* Day before the migration:

3. Make bugzilla readonly.

4. Import any new bugs created since the last import.

There may be commit access disruption during the migration, so 
completing these steps the day before will limit the amount of down time.

5. Temporarily re-enable issues in the llvm-project repo and copy existing issues
to the llvm-bug-archive repo so they get higher IDs numbers than any
existing PR.  Disable issues when done.

Note that we will copy issues instead of moving them, which means the original
issue will remain in tact.  This will allow us to retain the bug IDs
for future use and not 'lose' a bug ID.

* Day of migration:

6. Lockdown the repo as much as possible to prevent people from creating
issues or pull requests.

Temporarily making the repo private may be one way to achieve this.  Other
suggestions welcome.

7. Copy issues with overlapping issues IDs from the llvm-bug-archive repo
into the llvm-project repo.

Issues from the llvm-bug-archive repo that have the same ID number as
existing issues in the llvm-project repo will be manually copied from
the former to the later.  This will allow us to preserve the PR numbers
from bugzilla.  Here is an example for how this would work:

- Delete comments and description from llvm-project issue #1.
- Copy comments and description from llvm-bug-archive issue #1 into
  llvm-project issue #1.

Since GitHub issue and pull requests share the same numbering sequence, any
PR# from bugzilla that maps to a pull request in the llvm-project repo will
need to have it's comments copied into a pull request.  These issues will look slightly
strange since there will be random commits attached to the issue.  However,
all data will be preserved and more importantly the bug ID will be preserved.

The issues URL can be used to access pull requests e.g.
pull request #84 is accessible via github.com/llvm/llvm-project/issues/84
so even with bugzilla data stored in pull requests, we will still be able to do a simple redirect
from llvm.org/PR### to github.com/llvm/llvm-project/issues/###

8. Once all the overlapping Issue IDs have been copied.  Move the rest of the issues
from the llvm-bug-archive repo to the llvm-project repo.

This should be faster than doing the copies since we do not need to overwrite existing
issues and can just move the issues from one repo to the other.

The end result of this is that we have all the old bugs from bugzilla present as issues
in the llvm-project repository with all of their ID numbers preserved.

* Other action items:

- We need volunteers to help create bug templates to simplify the process of submitting
  bugs.  If you are interested in helping with this, let me know.

- Continue to iterate on the set of issue labels.  This should not block the migration since
labels can be changed at any time, but there were some suggested improvements that should
be discussed.

Please reply to this proposal with your questions, comments, praise, or concerns.


[1] https://help.github.com/en/github/building-a-strong-community/about-issue-and-pull-request-templates

On 04/20/2020 12:30 PM, Tom Stellard via llvm-dev wrote:
> Hi,
> I wanted to continue discussing the plan to migrate from Bugzilla to Github.
> It was suggested that I start a new thread and give a summary of the proposal
> and what has changed since it was originally proposed in October.
> == Here is the original proposal:
> http://lists.llvm.org/pipermail/llvm-dev/2019-October/136162.html
> == What has changed:
> * You will be able to subscribe to notifications for a specific issue
>   labels.  We have a proof of concept notification system using github actions
>   that will be used for this.
> * Emails will be sent to llvm-bugs when issues are opened or closed.
> * We have the initial list of labels: https://github.com/llvm/llvm-project/labels
> == Remaining issue:
> * There is one remaining issue that I don't feel we have consensus on,
> and that is what to do with bugs in the existing bugzilla.  Here are some options
> that we have discussed:
> 1. Switch to GitHub issues for new bugs only.  Bugs filed in bugzilla that are
> still active will be updated there until they are closed.  This means that over
> time the number of active bugs in bugzilla will slowly decrease as bugs are closed
> out.  Then at some point in the future, all of the bugs from bugzilla will be archived
> into their own GitHub repository that is separate from the llvm-project repo.
> 2. Same as 1, but also create a migration script that would allow anyone to
> manually migrate an active bug from bugzilla to a GitHub issue in the llvm-project
> repo.  The intention with this script is that it would be used to migrate high-traffic
> or important bugs from bugzilla to GitHub to help increase the visibility of the bug.
> This would not be used for mass migration of all the bugs.
> 3. Do a mass bug migration from bugzilla to GitHub and enable GitHub issues at the same time.
> Closed or inactive bugs would be archived into their own GitHub repository, and active bugs
> would be migrated to the llvm-project repo.
> The key difference between proposal 1,2 and 3, is when bugs will be archived from bugzilla
> to GitHub.  Delaying the archiving of bugs (proposals 1 and 2) means that we can migrate
> to GitHub issues sooner (within 1-2 weeks), whereas trying to archive bugs during the
> transition (proposal 3) will delay the transition for a while (likely several months)
> while we evaluate the various solutions for moving bugs from bugzilla to GitHub.
> The original proposal was to do 1 or 2, however there were some concerns raised on the list
> that having 2 different places to search for bugs for some period of time would
> be very inconvenient.  So, I would like to restart this discussion and hopefully we can
> come to some kind of conclusion about the best way forward.
> Thanks,
> Tom
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