[borinquenkid]

Fixes #15667 (a merge to 7.0.x does not close it, so it is closed by hand once the merge-ups land).

MongoDatastore.initializeIndices logged a MongoCommandException from createIndex at ERROR together with the exception. A server error such as 86 IndexKeySpecsConflict then printed a very long stack trace at every startup, for a condition the operator has to fix in the mapping or in the database.

Change: the ERROR event carries only the entity, the index definition (or property) and the server message, as before. The stack trace goes to a separate DEBUG event. This covers the three paths: a single index, a compound index and a property index.

Only the 7.x line. On 8.0.x and 8.1.x the reported case goes through reconcileIndexConflict (#15747, #16208), which logs a one-line "Index conflict ..." message and does not attach the exception, so nothing changes there. 7.1.x and 7.2.x do not have that code; the merge-ups carry this fix.

Tests: MongoDatastoreIndexFailureLogSpec creates name_1 with the driver in a MongoDB Testcontainer, then starts a MongoDatastore whose entity maps name as a unique index, which makes the server answer 86. It asserts one ERROR event with the entity name and the server message and no throwable, and a DEBUG event that carries the MongoCommandException. It failed before the change (the ERROR event carried the exception) and passes after. All 569 tests of grails-data-mongodb-core pass (0 failures, 19 skipped); CodeNarc and Checkstyle are clean.

Test dependency: the module's tests ran on slf4j-nop, which cannot capture log events. logback-classic (version managed by the BOM) replaces it as the single SLF4J binding of the tests, so the spec can attach a ListAppender; testRuntimeClasspath shows no second binding.

Two of the three reviewers (matrei, codeconsole, jdaugherty), as 7.0.x is released. The run ci label is set because 7.0.x skips the tests otherwise and the new spec needs the container.

https://claude.ai/code/session_01Dmki4RzWwreEC2GkkyFnvL

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[testlens-app]

✅ All tests passed ✅

🏷️ Commit: ac591ef
▶️ Tests: 51576 executed
⚪️ Checks: 58/58 completed

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[jamesfredley]

An index creation failure is still logged with the entity, the index, and the reason. The stack trace is at debug, and a success is not logged as a failure.