sql: add doctor check for parent schema in parent db

With this patch, doctor now also checks that the parent id of an object
matches the parent id of the parent schema of the object.

Fixes cockroachdb#55716.

Release note: None

pkg/sql/doctor/doctor.go

@@ -141,7 +141,7 @@ func ExamineDescriptors(
 		}
 
 		_, parentExists := descGetter[desc.GetParentID()]
-		_, parentSchemaExists := descGetter[desc.GetParentSchemaID()]
+		parentSchema, parentSchemaExists := descGetter[desc.GetParentSchemaID()]
 		switch d := desc.(type) {
 		case catalog.TableDescriptor:
 			if err := d.Validate(ctx, descGetter); err != nil {
@@ -161,15 +161,21 @@ func ExamineDescriptors(
 			// parent schema id is always 0.
 			parentSchemaExists = true
 		}
+		var invalidParentID bool
 		if desc.GetParentID() != descpb.InvalidID && !parentExists {
 			problemsFound = true
+			invalidParentID = true
 			fmt.Fprint(stdout, reportMsg(desc, "invalid parent id %d", desc.GetParentID()))
 		}
 		if desc.GetParentSchemaID() != descpb.InvalidID &&
-			desc.GetParentSchemaID() != keys.PublicSchemaID &&
-			!parentSchemaExists {
-			problemsFound = true
-			fmt.Fprint(stdout, reportMsg(desc, "invalid parent schema id %d", desc.GetParentSchemaID()))
+			desc.GetParentSchemaID() != keys.PublicSchemaID {
+			if !parentSchemaExists {
+				problemsFound = true
+				fmt.Fprint(stdout, reportMsg(desc, "invalid parent schema id %d", desc.GetParentSchemaID()))
+			} else if !invalidParentID && parentSchema.GetParentID() != desc.GetParentID() {
+				problemsFound = true
+				fmt.Fprint(stdout, reportMsg(desc, "invalid parent id of parent schema, expected %d, found %d", desc.GetParentID(), parentSchema.GetParentID()))
+			}
 		}
 
 		// Process namespace entries pointing to this descriptor.

pkg/sql/doctor/doctor_test.go

@@ -74,6 +74,10 @@ func TestExamineDescriptors(t *testing.T) {
 	descpb.TableFromDescriptor(droppedValidTableDesc, hlc.Timestamp{WallTime: 1}).
 		State = descpb.DescriptorState_DROP
 
+	inSchemaValidTableDesc := protoutil.Clone(validTableDesc).(*descpb.Descriptor)
+	descpb.TableFromDescriptor(inSchemaValidTableDesc, hlc.Timestamp{WallTime: 1}).
+		UnexposedParentSchemaID = 3
+
 	tests := []struct {
 		descTable      doctor.DescriptorTable
 		namespaceTable doctor.NamespaceTable
@@ -194,6 +198,31 @@ Database   1: ParentID   0, ParentSchemaID  0, Name 'db': not being dropped but
 			},
 			expected: `Examining 1 descriptors and 1 namespace entries...
     Type   1: ParentID   0, ParentSchemaID  0, Name 'type': invalid parentID 0
+`,
+		},
+		{
+			descTable: doctor.DescriptorTable{
+				{ID: 1, DescBytes: toBytes(t, inSchemaValidTableDesc)},
+				{
+					ID: 2,
+					DescBytes: toBytes(t, &descpb.Descriptor{Union: &descpb.Descriptor_Database{
+						Database: &descpb.DatabaseDescriptor{Name: "db", ID: 2},
+					}}),
+				},
+				{
+					ID: 3,
+					DescBytes: toBytes(t, &descpb.Descriptor{Union: &descpb.Descriptor_Schema{
+						Schema: &descpb.SchemaDescriptor{Name: "schema", ID: 3, ParentID: 0},
+					}}),
+				},
+			},
+			namespaceTable: doctor.NamespaceTable{
+				{NameInfo: descpb.NameInfo{ParentID: 2, ParentSchemaID: 3, Name: "t"}, ID: 1},
+				{NameInfo: descpb.NameInfo{Name: "db"}, ID: 2},
+				{NameInfo: descpb.NameInfo{ParentID: 0, Name: "schema"}, ID: 3},
+			},
+			expected: `Examining 3 descriptors and 3 namespace entries...
+   Table   1: ParentID   2, ParentSchemaID  3, Name 't': invalid parent id of parent schema, expected 2, found 0
 `,
 		},
 		{