[Bug] Guard schema changes against live Global Index references

[zhoulii]

Search before asking

• I searched in the issues and found nothing similar.

Paimon version

2.0

Compute Engine

flink

Minimal reproduce step

1. Create a table with row tracking and data evolution enabled.
2. Insert data and create a Global Index on a column.
3. Drop the indexed column.
4. Call drop_global_index for the removed column.
5. The procedure fails because the column no longer exists, while the Global Index remains referenced by the index manifest.

What doesn't meet your expectations?

Dropping a column succeeds even when it is referenced by live Global Index files. Afterward, drop_global_index cannot resolve the removed column to its field ID, leaving the index impossible to remove through the public procedure.

Schema changes that drop, rename, or change the type of an indexed column should be rejected and instruct the user to drop the complete Global Index first. This is consistent with the existing protection in SchemaManager#assertNotUpdatingPrimaryKeyIndexColumn .

Anything else?

No response

Are you willing to submit a PR?

• I'm willing to submit a PR!

[zhang-arvin]

I will work on this.