Context

For some unknown reason non-git-submodule testdata that interact with transactions fail with the following error:

[2025/04/01 18:38:26.175]     unified_spec_runner.go:139: error running operation "insertOne" at index 1: error verification failed: expected no error, but got (MigrationConflict) Transaction b0395ebd-5ecb-4262-abe2-8ae1e8841a42 - Il1bctjvfYRA0JpLUY4Xle2E6bw+KM1YpMr4x52qGgE= -  - :1 was aborted on statement 0 due to: a non-retryable snapshot error :: caused by :: Encountered error from localhost:27218 during a transaction :: caused by :: Database mongos-unpin-db has undergone a catalog change operation at time Timestamp(1743546632, 82) and no longer satisfies the requirements for the current transaction which requires Timestamp(1743546632, 81). Transaction will be aborted.

For example:

TestUnifiedSpec/transactions/tests/unified/mongos-unpin.json/unpin_after_TransientTransactionError_error_on_commit

In particular, these include

• unified-test-format/valid-pass
• transactions/unified
• convenient-transactions

Definition of done

Figure out why these tests have this problem and then remove them from the testdata directory in favor of their git submodule analogues. "convenient-transactions" should be removed from the legacy unified spec runner and the unified spec tests should be extended to include "transactions-convenient-api/tests/unified"

Pitfalls

It's notable that these errors are not even re-creatable in a spawn host in which they were original reported in EG. Additionally, their failures are consistent. It may be quite time consuming determining the source of this bug.