[OPENJPA-3002] Fix: @Index(columnNames) at field level is now correctly applied

[cwegener-79]

Fix: @Index(columnNames) at field level is silently ignored

Problem

The OpenJPA-specific @Index annotation (org.apache.openjpa.persistence.jdbc.Index) supports a columnNames attribute that allows explicitly defining which columns should be included in a database index when the annotation is placed on a field or method. However, these column names were silently ignored during annotation parsing.

Root cause: AnnotationPersistenceMappingParser.parseIndex(MappingInfo, Index) called an internal overload passing only name, enabled, and unique — idx.columnNames() was never forwarded:

// Before — columnNames dropped on the floor:
private void parseIndex(MappingInfo info, Index idx) {
    parseIndex(info, idx.name(), idx.enabled(), idx.unique());
}

As a result, any entity using @Index(columnNames = {"COL_A", "COL_B"}) at the field level would get a schema index with no explicitly defined columns.

Fix

• parseIndex(MappingInfo, Index) now passes idx.columnNames() to a new overload.
• New method parseIndex(MappingInfo, String, boolean, boolean, String[]) creates Column objects from the provided names and adds them to the Index schema object.
• The existing protected 4-parameter overload delegates to the new method with null column names, preserving backwards compatibility for subclasses.

Testing

Added a regression test that verifies the fix end-to-end:

• EntityWithIndexColumnNames — test entity with @Index(name="idx_col_a_b", columnNames={"COL_A","COL_B"}) on a field.
• TestIndexColumnNames#testFieldIndexColumnNamesAreApplied — asserts that after full mapping resolution the schema index contains both explicitly named columns. The test fails without the fix (getColumns().length == 0) and passes with it.

Changed Files

File	Change
AnnotationPersistenceMappingParser.java	Bug fix + whitespace/indentation cleanup
EntityWithIndexColumnNames.java	New test entity
TestIndexColumnNames.java	New regression test

[cwegener-79]

Just a quick nudge on this PR 🙂
I know @Index is not part of standard JPA, but I could make good use of this fix in a legacy project.
Please let me know if there’s anything I can do to help move this forward.

[solomax]

Could you please remove all whitespaces-only changes to AnnotationPersistenceMappingParser

Thanks in advance :)

[solomax]

@cwegener-79 could you please rebase this one? we just have merged huge new functionality (this is why merging was delayed)

[cwegener-79]

@cwegener-79 could you please rebase this one? we just have merged huge new functionality (this is why merging was delayed)

No Problem, I've just rebased it.

[solomax]

Thanks for the contribution!