A stale add_column reuses a dropped column's field id and schema id #4190

import tempfile
import pyarrow as pa
from pyiceberg.catalog.sql import SqlCatalog
from pyiceberg.types import StringType

cat = SqlCatalog("c", uri="sqlite:///:memory:", warehouse=f"file://{tempfile.mkdtemp()}")
cat.create_namespace("ns")
cat.create_table("ns.t", schema=pa.schema([("k", pa.int64())]))

a = cat.load_table("ns.t")
b = cat.load_table("ns.t")
with b.update_schema() as u:
    u.add_column("x", StringType())
b.append(pa.table({"k": [1], "x": ["a"]}))
with b.update_schema() as u:
    u.delete_column("x")

with a.update_schema() as u:
    u.add_column("y", StringType())
# commits, should raise CommitFailedException as the last assigned field id changed

t = cat.load_table("ns.t")
print(t.scan().to_arrow().to_pylist())
# [{'k': 1, 'x': 'a'}]: the dropped column is back with its data, and y is gone
print([(s.schema_id, [(f.field_id, f.name) for f in s.fields]) for s in t.metadata.schemas])
# [(0, [(1, 'k')]), (1, [(1, 'k'), (2, 'x')]), (1, [(1, 'k'), (2, 'y')])]
# y took field id 2 and schema id 1, both already x's