catalog: add maybeAddConstraintIDs to RestoreChanges

All backups taken in versions 22.1 and later should already have
constraint IDs set. Technically, now that we are in v24.1, we no longer
support restoring from versions older than 22.1, but we still have
tests that restore from old versions. Until those fixtures are updated,
we need to handle the case where constraint IDs are not set already when
restoring a backup.

To prove that this works, I've resurrected a different test that
restores from a v21.1 backup, which was earlier deleted in 8b56efd.

Release note: None

pkg/ccl/backupccl/testdata/backup-restore/show_backup

@@ -4,6 +4,15 @@
 new-cluster name=s1 allow-implicit-access localities=eu-central-1,eu-north-1,us-east-1
 ----
 
+link-backup cluster=s1 src-path=show_backup_validate,invalidDependOnBy_21.1 dest-path=invalidDependOnBy_21.1
+----
+
+# This backup intentionally has a dangling invalid depend on by reference.
+query-sql regex=invalid\sdepended-on-by
+SELECT * FROM [SHOW BACKUP VALIDATE FROM 'invalidDependOnBy_21.1' IN 'nodelocal://1/'];
+----
+true
+
 link-backup cluster=s1 src-path=show_backup_validate,valid-22.2 dest-path=valid-22.2
 ----
 

pkg/ccl/backupccl/testdata/show_backup_validate/invalidDependOnBy_21.1/BACKUP_MANIFEST-CHECKSUM

@@ -0,0 +1 @@
+'���

pkg/sql/catalog/post_deserialization_changes.go

@@ -82,6 +82,10 @@ const (
 	// references.
 	RemovedDuplicateIDsInRefs
 
+	// AddedConstraintIDs indicates that table descriptors had constraint ID
+	// added.
+	AddedConstraintIDs
+
 	// RemovedSelfEntryInSchemas corresponds to a change which occurred in
 	// database descriptors to recover from an earlier bug whereby when
 	// dropping a schema, we'd mark the database itself as though it was the

pkg/sql/catalog/tabledesc/table_desc_builder.go

@@ -178,6 +178,16 @@ func (tdb *tableDescriptorBuilder) RunRestoreChanges(
 		tdb.changes.Add(catalog.UpgradedSequenceReference)
 	}
 
+	// All backups taken in versions 22.1 and later should already have
+	// constraint IDs set. Technically, now that we are in v24.1, we no longer
+	// support restoring from versions older than 22.1, but we still have
+	// tests that restore from old versions. Until those fixtures are updated,
+	// we need to handle the case where constraint IDs are not set already.
+	// TODO(rafi): remove this once all fixtures are updated. See: https://github.com/cockroachdb/cockroach/issues/120146.
+	if changed := maybeAddConstraintIDs(tdb.maybeModified); changed {
+		tdb.changes.Add(catalog.AddedConstraintIDs)
+	}
+
 	// Upgrade the declarative schema changer state
 	if scpb.MigrateDescriptorState(version, tdb.maybeModified.ParentID, tdb.maybeModified.DeclarativeSchemaChangerState) {
 		tdb.changes.Add(catalog.UpgradedDeclarativeSchemaChangerState)
@@ -778,6 +788,102 @@ func maybeFixPrimaryIndexEncoding(idx *descpb.IndexDescriptor) (hasChanged bool)
 	return true
 }
 
+// maybeAddConstraintIDs ensures that all constraints have an ID associated with
+// them.
+func maybeAddConstraintIDs(desc *descpb.TableDescriptor) (hasChanged bool) {
+	// Only assign constraint IDs to physical tables.
+	if !desc.IsTable() {
+		return false
+	}
+	// Collect pointers to constraint ID variables.
+	var idPtrs []*descpb.ConstraintID
+	if len(desc.PrimaryIndex.KeyColumnIDs) > 0 {
+		idPtrs = append(idPtrs, &desc.PrimaryIndex.ConstraintID)
+	}
+	for i := range desc.Indexes {
+		idx := &desc.Indexes[i]
+		if !idx.Unique || idx.UseDeletePreservingEncoding {
+			continue
+		}
+		idPtrs = append(idPtrs, &idx.ConstraintID)
+	}
+	checkByName := make(map[string]*descpb.TableDescriptor_CheckConstraint)
+	for i := range desc.Checks {
+		ck := desc.Checks[i]
+		idPtrs = append(idPtrs, &ck.ConstraintID)
+		checkByName[ck.Name] = ck
+	}
+	fkByName := make(map[string]*descpb.ForeignKeyConstraint)
+	for i := range desc.OutboundFKs {
+		fk := &desc.OutboundFKs[i]
+		idPtrs = append(idPtrs, &fk.ConstraintID)
+		fkByName[fk.Name] = fk
+	}
+	for i := range desc.InboundFKs {
+		idPtrs = append(idPtrs, &desc.InboundFKs[i].ConstraintID)
+	}
+	uwoiByName := make(map[string]*descpb.UniqueWithoutIndexConstraint)
+	for i := range desc.UniqueWithoutIndexConstraints {
+		uwoi := &desc.UniqueWithoutIndexConstraints[i]
+		idPtrs = append(idPtrs, &uwoi.ConstraintID)
+		uwoiByName[uwoi.Name] = uwoi
+	}
+	for _, m := range desc.GetMutations() {
+		if idx := m.GetIndex(); idx != nil && idx.Unique && !idx.UseDeletePreservingEncoding {
+			idPtrs = append(idPtrs, &idx.ConstraintID)
+		} else if c := m.GetConstraint(); c != nil {
+			switch c.ConstraintType {
+			case descpb.ConstraintToUpdate_CHECK, descpb.ConstraintToUpdate_NOT_NULL:
+				idPtrs = append(idPtrs, &c.Check.ConstraintID)
+			case descpb.ConstraintToUpdate_FOREIGN_KEY:
+				idPtrs = append(idPtrs, &c.ForeignKey.ConstraintID)
+			case descpb.ConstraintToUpdate_UNIQUE_WITHOUT_INDEX:
+				idPtrs = append(idPtrs, &c.UniqueWithoutIndexConstraint.ConstraintID)
+			}
+		}
+	}
+	// Set constraint ID counter to sane initial value.
+	var maxID descpb.ConstraintID
+	for _, p := range idPtrs {
+		if id := *p; id > maxID {
+			maxID = id
+		}
+	}
+	if desc.NextConstraintID <= maxID {
+		desc.NextConstraintID = maxID + 1
+		hasChanged = true
+	}
+	// Update zero constraint IDs using counter.
+	for _, p := range idPtrs {
+		if *p != 0 {
+			continue
+		}
+		*p = desc.NextConstraintID
+		desc.NextConstraintID++
+		hasChanged = true
+	}
+	// Reconcile constraint IDs between enforced slice and mutation.
+	for _, m := range desc.GetMutations() {
+		if c := m.GetConstraint(); c != nil {
+			switch c.ConstraintType {
+			case descpb.ConstraintToUpdate_CHECK, descpb.ConstraintToUpdate_NOT_NULL:
+				if other, ok := checkByName[c.Check.Name]; ok {
+					c.Check.ConstraintID = other.ConstraintID
+				}
+			case descpb.ConstraintToUpdate_FOREIGN_KEY:
+				if other, ok := fkByName[c.ForeignKey.Name]; ok {
+					c.ForeignKey.ConstraintID = other.ConstraintID
+				}
+			case descpb.ConstraintToUpdate_UNIQUE_WITHOUT_INDEX:
+				if other, ok := uwoiByName[c.UniqueWithoutIndexConstraint.Name]; ok {
+					c.UniqueWithoutIndexConstraint.ConstraintID = other.ConstraintID
+				}
+			}
+		}
+	}
+	return hasChanged
+}
+
 // maybeRemoveDuplicateIDsInRefs ensures that IDs in references to other tables
 // are not duplicated.
 func maybeRemoveDuplicateIDsInRefs(d *descpb.TableDescriptor) (hasChanged bool) {