[SOLR-17323] Fix potential ConcurrentModificationException on CachingDirectoryFactory.close()

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 9.6
• Fix Version/s: 9.7
• Assignee: Michael Gibney
• Reporter: Michael Gibney
• Created: 07/Jun/24 03:04
• Updated: 17/Jun/24 12:47
• Resolved: 17/Jun/24 12:47

Description

While working on SOLR-16962, this CI run encountered a ConcurrentModificationException on CachingDirectoryFactory.close().

It's unclear to me whether this issue existed before 9.6, but it may at least have been exacerbated by SOLR-16866 (since previously the directory-removal-reordering logic wasn't doing much of anything).

In any case, the fix is straightforward. I'm not aware of this issue ever hitting in the wild, fwiw; and if it did, I'm not sure how much of a problem it would be, given that it would hit only during DirectoryFactory.close() (at which point things are shutting down anyway).

Issue Links

• links to: GitHub Pull Request #2505