spring-data-mongodb-4812

Minimal reproducible example for Spring Data MongoDB issue #4812

Minimal conversion example

See AggregationContextTest for a minimal sample to reproduce the issue. The test parses a document and then converts it using AggregationContext#getMappedObject. The test fails, due to the args array being converted from empty array to null.

Realistic example

See AggregatorIT for a real life example. The class under test creates an aggregation pipeline via the Aggregation API, which works correctly, and via parsing a json to create a pre-rendered Document. The latter fails when sent to MongoDB.

A workaround is provided where an unused argument is specified, preventing the conversion to null.