ocabot migration module_name from old_module_name old_repo

[hparfr]

Nowadays, it happens frequently to see modules moved to new repo or renamed.
It's hard to keep track of these changes. When searching for a module in a newer version, it's quite common to start by looking in the repo on the PRs or in the Migration issues.

Is your feature request related to a problem?

Module xxx is on oca/some-repo in 15.0, 16.0.
For 18.0, module xxx is renamed in xxy and put on oca/some-other-repo.
No one took care of porting this module in 17.0 yet.

Then, one day, someone searched for xxx for 18.0 in oca/some-repo#18.0 and oca/some-repo#17.0 and did not find anything.
So she start the migration of xxx on oca/some-repo#18.0 and create a PR on some-repo

One of the PSC read the PR and did not remember of move+rename to xxy on oca/some-other-repo#18.0.
Maybe it was too long ago, maybe the PSC was not PSC at the time of the move, maybe the PSC just forgot about this move...
Anyway, our PSC throws a /ocabot migration xxx in the PR, ocabot creates an entry in the migration issue 18.0 on oca/some-repo.

When this PR is merged, I guess the publishing on pypi will fail. It will be late.
It's frustrating for the dev and the reviewers of the useless PR.
It's harder for all other users to find the new version of a module if it has been moved / renamed.

Describe the solution you'd like

In the PR adding the module xxy on oca/some-other-repo, a PSC will put a different message:
/ocabot migration xxy from xxx@some-repo

If the present PR is a merge of differents modules, it will be:
/ocabot migration xxy from xxx@some-repo xxz@some-other-repo

If the present PR contains a split of modules, two messages should be posted:
/ocabot migration xxy from xxx@some-repo
then in another message:
/ocabot migration xxw from xxx@some-repo

It should create:

1. in issue Migration to version 18.0 on oca/some-other-repo add an entry to this PR.

xxx - By someuser - https://github.com/OCA/some-other-repo/pull/123

2. in issue Migration to version 18.0 on oca/some-repo add en entry to this PR

xxx moved to xxy on oca/some-other-repo - By someuser - https://github.com/OCA/some-other-repo/pull/123

Describe alternatives you've considered

A clear and concise description of any alternative solutions or features you've considered.

1. In the commit message or the PR description a command can be set to instruct the change.
2. It can also be a special file stripped out during the merge.
3. a new key in the manifest

I think the proposed solution /ocabot migration module_name from module_name@original_repo is simpler for PSC to apply and more safe to parse.

At first, the PSC should have rights to both repo, the actual and the new. In that way the permission already in place is kept.

Additional context

Having this feature, will improve the issue #318

[florian-dacosta]

I think this is a good idea.
It won't be much work for PSCs to give the information of a repository change of module name change but can save quite some time for developpers that were not aware of such changes.