OutOfMemoryError during git fetch in Sourcetree 3.4.8

Answer

Upgrading to Sourcetree 3.4.10 eliminates the java.lang.OutOfMemoryError caused by the JGit resource leak, provided the JVM heap is sufficient for the repository size.

Confirmed facts (from the 3.4.10 release notes)

• The default JVM heap limit was raised to 1 GB.
• RevWalk and ObjectLoader objects are now closed in a finally block, fixing the memory leak.
• Internal testing showed an ≈80 % reduction in memory growth during repeated fetches.

Likely explanation for remaining behavior

The JGit worker and the fetch‑progress UI still run on the same Swing thread. Even with enough heap, a large fetch blocks the UI until the worker finishes, which appears as a freeze. The 3.4.10 patch does not change this threading model.

Steps to verify and mitigate

1. Confirm you are running Sourcetree 3.4.10 or later (Help → About Sourcetree).
2. If you still see OutOfMemoryError, increase the heap via the Sourcetree VM options (e.g., add -Xmx2g to %APPDATA%\Atlassian\SourceTree\sourcetree.vmoptions on Windows or the equivalent plist on macOS) and restart.
3. During a fetch of a repository >2 GB, monitor heap usage with VisualVM or JConsole attached to the Sourcetree JVM; the heap should stay below the configured limit.
4. Observe the UI: if the interface becomes unresponsive for the duration of the fetch, the freeze is due to the shared thread, not memory exhaustion.
5. To avoid the UI block, consider using the command‑line git fetch for very large repos, or disable the fetch progress dialog in Sourcetree preferences (if available).

Missing diagnostic detail

If after increasing the heap you still encounter an OutOfMemoryError, please provide the observed heap usage (maximum and committed) during the fetch so we can determine whether the limit needs further raising.