TheR1sing3un opened a new pull request, #8187:
URL: https://github.com/apache/paimon/pull/8187

   Read-time schema evolution previously aligned only top-level columns by 
field id; sub-fields inside a ROW (and a ROW nested in an ARRAY/MAP) could not 
evolve: adding one silently created a top-level column, and 
rename/drop/update-type raised because the schema manager only handled the last 
path element.
   
   - Assign globally-unique ids to nested sub-fields at create time and compute 
highestFieldId recursively, so nested ids never collide with top-level ones.
   - Recurse schema changes along the dotted field-name path (transparently 
through ARRAY/MAP wrappers) for add/rename/drop/update-type/update-nullability/ 
update-comment, allocating new ids from the persisted highestFieldId.
   - Validate update-column-type against the cast-support rules.
   - Align nested sub-fields by field id at read time: reorder, pad missing 
with NULL, follow renames, and cast changed types, recursing into 
struct/array/map.
   
   Add tests covering nested add/rename/drop/update-type round-trips 
(append-only and primary-key), ARRAY<ROW>/MAP<.,ROW> sub-fields, the id model, 
and the cast rules.
   
   ### Purpose
   
   ### Tests
   


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