Bamboo always performs a full fetch when building new commits

Issue Summary

Bamboo always performs a full repository fetch when building new commits even when Fetch whole repository is unchecked.

Steps to Reproduce

1. Set up a plan with a Git repository and checkout task
2. Push a new commit
3. Run the build

Expected Results

Bamboo fetches only the branch specified on the repository

Actual Results

Bamboo always performs a full repository fetch, even though the revision exists on the configured branch. The below is observed in the build log :

simple	03-Dec-2019 02:40:20	Enforcing full fetch as requested revision has not been found on the configured branch
...
simple	03-Dec-2019 02:40:20	/usr/bin/git ... fetch --tags http://bitbucket:7990/scm/git/repo.git +refs/heads/*:refs/heads/* --update-head-ok --progress --verbose

Checkout times are increased and extra load is placed on repository hosts.

Note

This is normal behaviour if building with a custom revision and that revision doesn't exist on the branch configured on the repository. It may explain why you continue to see this message if running a fixed version of Bamboo with certain builds.

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available