#4094 Prefer uses methods when nested target options are only ignores - #4109

Summary

With @BeanMapping(ignoreByDefault = true), combining a whole-property mapping and a nested path ignore:

@Mapping(target = "relatedPerson", source = "relatedPerson")
@Mapping(target = "relatedPerson.relatedInformation", ignore = true)
@BeanMapping(ignoreByDefault = true)
PersonInformationDto toDto(PersonInformation source);

caused MapStruct to always forge a nested personToPersonDto method instead of using a suitable method from Mapper#uses. Because the forged method inherited ignoreByDefault and only carried the nested ignore, it mapped nothing — silent data loss. Removing the redundant nested ignore restored correct delegation.

Fix

1. PropertyMapping: when nested forge options are ignore-only, try existing mapping method selection first (same path as a plain property mapping), and only forge if none is found.
2. BeanMappingMethod: for forged methods that only carry ignore references, do not let parent ignoreByDefault suppress name-based mapping (so same-named properties still map when no uses method exists). Positive nested mappings under ignoreByDefault (e.g. ToolBox / Ignore mappings by default #1392) are unchanged.
3. MappingReferences#containsOnlyIgnoreMappings helper.

Fixes #4094

Changes

• PropertyMapping, BeanMappingMethod, MappingReferences
• Processor tests in org.mapstruct.ap.test.bugs._4094 (uses mapper + without uses)
• NEXT_RELEASE_CHANGELOG.md

Test plan

• Issue4094Test (6 runs: eclipse + javac) — green
• Regression: IgnorePropertyTest (ignore / expand / inherit), Issue2278Test — green

export JAVA_HOME=…/jdk-21
./mvnw -pl processor -am test \
  -Dtest=Issue4094Test,IgnorePropertyTest,Issue2278Test \
  -Dsurefire.failIfNoSpecifiedTests=false