Merge pull request #71421 from dt/backport21.2-71161

release-21.2: backupccl: fix bug when restoring a table with existing UDT

pkg/ccl/backupccl/backup_test.go

@@ -8759,3 +8759,26 @@ DROP TABLE foo;
 	defer cleanupEmptyCluster()
 	sqlDBRestore.Exec(t, "RESTORE FROM $1 AS OF SYSTEM TIME "+aost, LocalFoo)
 }
+
+// TestRestoreRemappingOfExistingUDTInColExpr is a regression test for a nil
+// pointer exception when restoring tables that point to existing types. When
+// updating the back references of the existing types we would index into a map
+// keyed on pre-rewrite IDs using a post rewrite ID.
+func TestRestoreRemappingOfExistingUDTInColExpr(t *testing.T) {
+	defer leaktest.AfterTest(t)()
+	defer log.Scope(t).Close(t)
+
+	const numAccounts = 1
+	_, _, sqlDB, _, cleanupFn := BackupRestoreTestSetup(t, singleNode, numAccounts, InitManualReplication)
+	defer cleanupFn()
+
+	sqlDB.Exec(t, `
+CREATE TYPE status AS ENUM ('open', 'closed', 'inactive');
+CREATE TABLE foo (id INT PRIMARY KEY, what status default 'open');
+BACKUP DATABASE data to 'nodelocal://0/foo';
+DROP TABLE foo CASCADE;
+DROP TYPE status;
+CREATE TYPE status AS ENUM ('open', 'closed', 'inactive');
+RESTORE TABLE foo FROM 'nodelocal://0/foo';
+`)
+}

pkg/ccl/backupccl/restore_job.go

@@ -1142,8 +1142,21 @@ func createImportingDescriptors(
 		}
 	}
 
-	// Assign new IDs to all of the type descriptors that need to be written.
-	if err := rewriteTypeDescs(typesToWrite, details.DescriptorRewrites); err != nil {
+	// Perform rewrites on ALL type descriptors that are present in the rewrite
+	// mapping.
+	//
+	// `types` contains a mix of existing type descriptors in the restoring
+	// cluster, and new type descriptors we will write from the backup.
+	//
+	// New type descriptors need to be rewritten with their generated IDs before
+	// they are written out to disk.
+	//
+	// Existing type descriptors need to be rewritten to the type ID of the type
+	// they are referring to in the restoring cluster. This ID is different from
+	// the ID the descriptor had when it was backed up. Changes to existing type
+	// descriptors will not be written to disk, and is only for accurate,
+	// in-memory resolution hereon out.
+	if err := rewriteTypeDescs(types, details.DescriptorRewrites); err != nil {
 		return nil, nil, err
 	}
 
@@ -1316,7 +1329,11 @@ func createImportingDescriptors(
 					return err
 				}
 				typeIDs, _, err := table.GetAllReferencedTypeIDs(dbDesc, func(id descpb.ID) (catalog.TypeDescriptor, error) {
-					return typesByID[id], nil
+					t, ok := typesByID[id]
+					if !ok {
+						return nil, errors.AssertionFailedf("type with id %d was not found in rewritten type mapping", id)
+					}
+					return t, nil
 				})
 				if err != nil {
 					return err

pkg/ccl/backupccl/restore_planning.go

@@ -666,8 +666,8 @@ func allocateDescriptorRewrites(
 
 				if parentDB.IsMultiRegion() && table.GetLocalityConfig() != nil {
 					// We're restoring a table and not its parent database. We may block
-					// restoring multi-region tables to multi-region databases since regions
-					// may mismatch.
+					// restoring multi-region tables to multi-region databases since
+					// regions may mismatch.
 					if err := checkMultiRegionCompatible(ctx, txn, p.ExecCfg().Codec, table, parentDB); err != nil {
 						return pgerror.WithCandidateCode(err, pgcode.FeatureNotSupported)
 					}