Off-by-one error in parallel test worker index validation

[Shashank Kushwaha]

In django/test/runner.py, the validation of _worker_id uses:

if _worker_id > len(db_aliases):

However, valid worker IDs should range from 0 to len(db_aliases) - 1.

For example, if len(db_aliases) = 3, valid IDs are 0, 1, and 2. The current condition allows _worker_id == 3, which is invalid.

This appears to be an off-by-one error and should likely use:

if _worker_id >= len(db_aliases):

This was observed while reviewing PR #20971.

[Shashank Kushwaha]

i'd like to work on this , if accepted.

[Shashank Kushwaha]

It looks like this issue has been addressed in PR #20971 by adding validation for _worker_id >= len(db_aliases) before usage.

I’m marking this as fixed. Happy to close if no further action is needed.

[Jacob Walls]

Duplicate of #27734