From af9d6fb8621f0222e22de5aaafc4014d545633cb Mon Sep 17 00:00:00 2001
From: Marius Posta <marius@cockroachlabs.com>
Date: Tue, 12 Jan 2021 13:37:58 -0500
Subject: [PATCH] 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 #55716.

Release note: None
---
 pkg/sql/doctor/doctor.go      | 16 +++++++++++-----
 pkg/sql/doctor/doctor_test.go | 29 +++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/pkg/sql/doctor/doctor.go b/pkg/sql/doctor/doctor.go
index 2dcfc761397b..e0fcd2708511 100644
--- a/pkg/sql/doctor/doctor.go
+++ b/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.
diff --git a/pkg/sql/doctor/doctor_test.go b/pkg/sql/doctor/doctor_test.go
index 9a57ae0b2986..21575b94ee8f 100644
--- a/pkg/sql/doctor/doctor_test.go
+++ b/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
 `,
 		},
 		{