Merge pull request #127455 from cockroachdb/blathers/backport-release…

…-24.2-127247

release-24.2: sql: cannot drop enum values if referenced in index expressions

pkg/sql/logictest/testdata/logic_test/alter_type

@@ -693,6 +693,7 @@ ALTER TYPE typ_110827 DROP VALUE 'a';
 statement error pgcode 2BP01 could not remove enum value "b" as it is being used by table ".*t_110827"
 ALTER TYPE typ_110827 DROP VALUE 'b';
 
+
 subtest end
 
 # We accidentally introduced a regression formatting dependent rows out,
@@ -711,3 +712,23 @@ statement error pgcode 2BP01 could not remove enum value "a" as it is being used
 ALTER TYPE typ_127136 DROP VALUE 'a';
 
 subtest end
+
+# Previously, we did not properly handle scanning index expressions for type
+# references when removing an enum value (#127147).
+subtest validate_type_in_index_expr
+
+statement ok
+CREATE TYPE typ_127147 AS ENUM ('a', 'b', 'c');
+CREATE TABLE t (x TEXT PRIMARY KEY, INDEX ((x::typ_127147)));
+INSERT INTO t VALUES ('a');
+
+statement error pgcode 2BP01 could not remove enum value "a" as it is being used by "t" in row: x='a'
+ALTER TYPE typ_127147 DROP VALUE 'a';
+
+statement ok
+TRUNCATE TABLE t;
+
+statement ok
+ALTER TYPE typ_127147 DROP VALUE 'a';
+
+subtest end

pkg/sql/type_change.go

@@ -837,6 +837,19 @@ func (t *typeSchemaChanger) canRemoveEnumValueFromTable(
 		}
 	}
 
+	// If the descriptor has any inaccessible columns, we need to scan those.
+	var syntheticDescs []catalog.Descriptor
+	if len(desc.AccessibleColumns()) != len(desc.PublicColumns()) {
+		descBuilder := desc.NewBuilder()
+		fullyAccessibleDesc := descBuilder.BuildExistingMutable().(*tabledesc.Mutable)
+		for colIdx := range fullyAccessibleDesc.Columns {
+			if col := &fullyAccessibleDesc.Columns[colIdx]; col.Inaccessible {
+				col.Inaccessible = false
+			}
+		}
+		syntheticDescs = []catalog.Descriptor{descBuilder.BuildImmutable().(catalog.TableDescriptor)}
+	}
+
 	var query strings.Builder
 	colSelectors := tabledesc.ColumnsSelectors(desc.AccessibleColumns())
 	columns := tree.AsStringWithFlags(&colSelectors, tree.FmtSerializable)
@@ -984,7 +997,12 @@ func (t *typeSchemaChanger) canRemoveEnumValueFromTable(
 			User:     username.NodeUserName(),
 			Database: dbDesc.GetName(),
 		}
-		rows, err := txn.QueryRowEx(ctx, "count-value-usage", txn.KV(), override, query.String())
+		var rows tree.Datums
+		err = txn.WithSyntheticDescriptors(syntheticDescs, func() error {
+			var err error
+			rows, err = txn.QueryRowEx(ctx, "count-value-usage", txn.KV(), override, query.String())
+			return err
+		})
 		if err != nil {
 			return errors.Wrapf(err, validationErr, member.LogicalRepresentation)
 		}