fix(datatypes): manually cast the type of pos to int16 for `table…

….info()` (#9139)

ibis/backends/tests/test_generic.py

@@ -617,6 +617,23 @@ def test_table_info(alltypes):
     assert expr.columns == list(df.columns)
 
 
+@pytest.mark.notyet(
+    ["druid"],
+    raises=PyDruidProgrammingError,
+    reason="Druid only supports trivial unions",
+)
+@pytest.mark.notyet(
+    ["flink"], reason="IOException - Insufficient number of network buffers"
+)
+def test_table_info_large(con):
+    num_cols = 129
+    col_names = [f"col_{i}" for i in range(num_cols)]
+    t = ibis.memtable({col: [0, 1] for col in col_names})
+    result = con.execute(t.info())
+    assert list(result.name) == col_names
+    assert result.pos.dtype == np.int16
+
+
 @pytest.mark.notimpl(
     [
         "datafusion",

ibis/expr/types/relations.py

@@ -2865,7 +2865,7 @@ def info(self) -> Table:
                 nulls=lambda t: t.isna.sum(),
                 non_nulls=lambda t: (1 - t.isna).sum(),
                 null_frac=lambda t: t.isna.mean(),
-                pos=lit(pos),
+                pos=lit(pos, type=dt.int16),
             )
             aggs.append(agg)
         return ibis.union(*aggs).order_by(ibis.asc("pos"))