Ben Bucksch wrote on 21.11.17 00:25:

I stand corrected. Somebody did an "import" to hg in 2008 and dropped
all history prior to that point. hg doesn't have any history before
2008. But with some effort, the git version of the c-c repo could import
the CVS history, though.

For gecko-dev, that's what they did. The history includes changes from
1998 in CVS.

On 20-11-2017 23:09, ace wrote:

Yes, they would work with similar speed as on m-c now.

Yes, history can and should be preserved.

This depends on where the repository lives physically.
For the general mozilla-central default branch, we can have hooks client
and/or server side that warn if you accidentally try to change things that are
not comm only code. It might not always be crystal clear like it is now.

 -Magnus

On 20-11-2017 23:22, Philipp Kewisch wrote:

The relevant folks are really the Thunderbird community, hence this mail :)
We need buy-in from Mozilla if we want to have the comm-central branch
physically on the mozilla hg server, in the mozilla-central repository. But
that is a secondary question, as if we get a NO we just have our branch live
elsewhere.

 -Magnus

On 11/21/17 12:40 AM, Ben Bucksch wrote:

See also https://github.com/ehsan/mozilla-cvs-history/

Philipp

On 11/21/17 9:22 AM, Magnus Melin wrote:

Hey Magnus,

sorry looks like I misunderstood. I though this was reopening the
possibility to merge c-c into the real m-c repo, for which we need m-c
folks to chime in.

Of course if we have something separate then that is up to us. I'm not
opposed, although I agree with Tom let's see if we can get TC working
first :)

Philipp

On 11/20/2017 6:40 PM, Ben Bucksch wrote:

Integrating CVS history for comm-central is challenging. If you include
a putative mozilla-central merge, we would have at least four separate
imports from CVS to hg happening at four separate times. The gecko-dev
CVS history does not include mailnews code, so cross-module commits
would require a great deal of fudging anyways. We also have at least two
or three copies of files that were imported from mozilla-central, some
with history, some without.

--
Joshua Cranmer
Thunderbird and DXR developer
Source code archæologist

Joshua Cranmer 🐧 wrote on 22.11.17 05:51:

These are good points, but we don't need to be perfect. Currently, we
have no history before 2008 at all, so if we get 90% or even 80% of the
history from CVS, that's still a huge improvement.

If we do use git, it would be fairly simple:

1. Base on gecko-dev (m-c in git). That already includes the hg history
   and CVS history of mozilla-central, up to this hour.

2. Make a new git branch, import CVS history of mailnews/ (and
   siblings), and only those. During import, you can filter by directory.
   That takes care of the cross-module commits where the same commit
   contains changes in mailnews/ and toolkit/ . The new imported commit
   would contain only the mailnews/ changes. The toolkit/ changes are
   already in gecko-dev. So, the commit would be split, but that doesn't
   hurt a lot, given that it's pre-2008. Better than not having any history
   at all.

3. Import hg history of mailnews/ on top.

4. Merge the above into our copy of gecko-dev.

5. Checkout and verify that it's identical to a checkout from our
   current hg repo.

Ben