Merge branch '23223-group-deletion-race-condition' into 'master'

Remove race condition while deleting groups

## What does this MR do?

The intended flow during a group deletion is:

```
  Soft-delete group (sync) -> Delete group projects (async) -> Hard-delete group (async)
```

The soft-delete was run in a transaction, which was committed only after
the async job (for hard-deletion) was kicked off. There was a race
condition here - the soft-delete transaction could complete _after_ the
hard delete completed, leaving a soft-deleted record in the database.

This MR removes this race condition. There is no need to run the
soft-delete in a transaction. The soft-delete completes before the async
job is kicked off.

This MR also adds a migration to delete all existing (soft-deleted) groups left in an inconsistent state
due to this bug.

- Closes #23223 
- EE merge request: gitlab-org/gitlab-ee!886

See merge request !7528

1 files changed, 4 insertions, 0 deletions

diff --git a/changelogs/unreleased/23223-group-deletion-race-condition.yml b/changelogs/unreleased/23223-group-deletion-race-condition.yml
new file mode 100644
index 00000000000..6f22e85fb4b
--- /dev/null
+++ b/changelogs/unreleased/23223-group-deletion-race-condition.yml
@@ -0,0 +1,4 @@
+---
+title: Fix race condition during group deletion and remove stale records present due to this bug
+merge_request: 7528
+author: Timothy Andrew