Ref T13546. When users hit a situation where we would select "squash" but would previously select "merge", prevent them from continuing under ambiguous conditions.
- Maniphest Tasks
- T13546: Modernize the "arc land" workflow
- rARC78e9cc9c0129: Add a check for ambiguous merge strategies after the "history.immutable"…
Ran "arc land" in Git with "history.immutable" true, false, and not configured.