Job timeout risk: spec/models/merge_request_diff_spec.rb ran much longer than expected

Why was this issue created?

spec/models/merge_request_diff_spec.rb was reported to have:

1. exceeded Knapsack's expected runtime by at least 50%, and
2. been identified as a notable pipeline bottleneck and a job timeout risk

Suggested steps for investigation

1. To reproduce in CI by running test files in the same order, you can follow the steps listed here.
2. Identify if a specific test case is stalling the run time. Hint: You can search the job's log for Starting example group spec/models/merge_request_diff_spec.rb and view the elapsed time after each test case in the proceeding lines starting with [RSpecRunTime].
3. If the test file is large, consider refactoring it into multiple files to allow better test parallelization across runners.
4. If the run time cannot be fixed in time, consider quarantine the spec(s) to restore performance.

Run time details

• Reported from pipeline 2976162 created at 2024-07-08T01:16:08Z

Field	Value
Job URL	rspec-unit-pg14-single-db-ci-connection-10-32
Job total RSpec suite run time	expected: 38 minutes 16.66 seconds, actual: 76 minutes 22.79 seconds
Spec file run time	expected: 7 minutes 30.65 seconds, actual: 12 minutes 43.06 seconds
Spec file weight	16.65% of total suite run time

• Reported from pipeline 2985933 created at 2024-07-10T01:15:58Z

Field	Value
Job URL	rspec-unit-pg14-single-db-ci-connection-7-32
Job total RSpec suite run time	expected: 40 minutes 36.58 seconds, actual: 79 minutes 51.1 seconds
Spec file run time	expected: 8 minutes 17.14 seconds, actual: 12 minutes 43.08 seconds
Spec file weight	15.93% of total suite run time

• Reported from pipeline 3248526 created at 2024-09-26T01:15:52Z

Field	Value
Job URL	rspec-unit-pg14-single-db-ci-connection-11-44
Job total RSpec suite run time	expected: 44 minutes 17.64 seconds, actual: 70 minutes 51.6 seconds
Spec file run time	expected: 9 minutes 28.18 seconds, actual: 16 minutes 3.36 seconds
Spec file weight	22.66% of total suite run time

• Reported from pipeline 3478959 created at 2024-11-21T01:15:47Z

Field	Value
Job URL	rspec-unit-pg16-10-44
Job total RSpec suite run time	expected: 26 minutes 54.74 seconds, actual: 72 minutes 20.36 seconds
Spec file run time	expected: 6 minutes 28.89 seconds, actual: 16 minutes 9.62 seconds
Spec file weight	22.34% of total suite run time

• Reported from pipeline 4118606 created at 2025-05-06T01:15:57Z

Field	Value
Job URL	rspec-unit-pg16-single-db-10-44
Job total RSpec suite run time	expected: 27 minutes 11.52 seconds, actual: 79 minutes 50.42 seconds
Spec file run time	expected: 6 minutes 52.67 seconds, actual: 16 minutes 22.68 seconds
Spec file weight	20.51% of total suite run time

• Reported from pipeline 4193861 created at 2025-05-25T01:15:51Z

Field	Value
Job URL	rspec-unit-pg16-12-44
Job total RSpec suite run time	expected: 26 minutes 32.68 seconds, actual: 77 minutes 25.48 seconds
Spec file run time	expected: 6 minutes 30.15 seconds, actual: 13 minutes 8.65 seconds
Spec file weight	16.98% of total suite run time

• Reported from pipeline 4217780 created at 2025-06-01T01:16:13Z

Field	Value
Job URL	rspec-unit-pg16-single-db-9-44
Job total RSpec suite run time	expected: 27 minutes 39.62 seconds, actual: 80 minutes 0.19 second
Spec file run time	expected: 6 minutes 59.76 seconds, actual: 15 minutes 34.15 seconds
Spec file weight	19.46% of total suite run time

• Reported from pipeline 4782410 created at 2025-10-27T19:25:17Z

Field	Value
Job URL	rspec-unit-pg16-single-db-ci-connection-8-44
Job total RSpec suite run time	expected: 36 minutes 16.88 seconds, actual: 70 minutes 13.65 seconds
Spec file run time	expected: 9 minutes 35.54 seconds, actual: 26 minutes 16.34 seconds
Spec file weight	37.41% of total suite run time

• Reported from pipeline 4868340 created at 2025-11-17T22:16:53Z

Field	Value
Job URL	rspec-unit-pg16-8-44
Job total RSpec suite run time	expected: 37 minutes 18.91 seconds, actual: 70 minutes 17.11 seconds
Spec file run time	expected: 9 minutes 43.89 seconds, actual: 15 minutes 43.45 seconds
Spec file weight	22.37% of total suite run time

• Reported from pipeline 4873012 created at 2025-11-18T18:36:09Z

Field	Value
Job URL	rspec-unit-pg16-single-db-8-44
Job total RSpec suite run time	expected: 37 minutes 16.02 seconds, actual: 79 minutes 45.41 seconds
Spec file run time	expected: 9 minutes 8.22 seconds, actual: 24 minutes 25.88 seconds
Spec file weight	30.63% of total suite run time