Last commit date of a branch is taken from the Author Date of the commit when using JGit in Bamboo

Summary

The last_commit_date stored against a branch in branch_commit_info is set from the AuthorDate instead of the CommitDate of a git commit when JGit (no native git) is used. When native git is used, the last_commit_date is correctly set to the CommitDate.

Steps to Reproduce

1. Make a commit to a branch so that the latest commit has a different commit date and author date. E.g. git cherry-pick
2. Ensure that no native git capability is defined so that JGit is utilized
3. Create a plan in Bamboo using that repository
4. Create the branch manually that you committed to

Expected Results

last_commit_date stored against a branch in branch_commit_info is set from the CommitDate

Actual Results

last_commit_date stored against a branch in branch_commit_info is set from the AuthorDate
This can result in branches being detected for deletion earlier than expected.

Workaround

Install native git on the Bamboo Server and define a capability for it at Bamboo Administration > Overview > Server Capabilities

The last_commit_date on an affected branch won't be updated using the CommitDate until a new commit is made.