ddl: fix issue of add foreign key failed but doesn't rollback

ddl/foreign_key.go

@@ -44,6 +44,9 @@ func (w *worker) onCreateForeignKey(d *ddlCtx, t *meta.Meta, job *model.Job) (ve
 		job.State = model.JobStateCancelled
 		return ver, errors.Trace(err)
 	}
+	if job.IsRollingback() {
+		return dropForeignKey(d, t, job, tblInfo, fkInfo.Name)
+	}
 	switch job.SchemaState {
 	case model.StateNone:
 		err = checkAddForeignKeyValidInOwner(d, t, job.SchemaName, tblInfo, &fkInfo, fkCheck)
@@ -63,7 +66,7 @@ func (w *worker) onCreateForeignKey(d *ddlCtx, t *meta.Meta, job *model.Job) (ve
 	case model.StateWriteOnly:
 		err = checkForeignKeyConstrain(w, job.SchemaName, tblInfo.Name.L, &fkInfo, fkCheck)
 		if err != nil {
-			job.State = model.JobStateCancelled
+			job.State = model.JobStateRollingback
 			return ver, err
 		}
 		tblInfo.ForeignKeys[len(tblInfo.ForeignKeys)-1].State = model.StateWriteReorganization
@@ -94,54 +97,46 @@ func onDropForeignKey(d *ddlCtx, t *meta.Meta, job *model.Job) (ver int64, _ err
 		return ver, errors.Trace(err)
 	}
 
-	var (
-		fkName model.CIStr
-		found  bool
-		fkInfo model.FKInfo
-	)
+	var fkName model.CIStr
 	err = job.DecodeArgs(&fkName)
 	if err != nil {
 		job.State = model.JobStateCancelled
 		return ver, errors.Trace(err)
 	}
+	return dropForeignKey(d, t, job, tblInfo, fkName)
+}
 
+func dropForeignKey(d *ddlCtx, t *meta.Meta, job *model.Job, tblInfo *model.TableInfo, fkName model.CIStr) (ver int64, err error) {
+	var fkInfo *model.FKInfo
 	for _, fk := range tblInfo.ForeignKeys {
 		if fk.Name.L == fkName.L {
-			found = true
-			fkInfo = *fk
+			fkInfo = fk
+			break
 		}
 	}
-
-	if !found {
+	if fkInfo == nil {
 		job.State = model.JobStateCancelled
 		return ver, infoschema.ErrForeignKeyNotExists.GenWithStackByArgs(fkName)
 	}
-
 	nfks := tblInfo.ForeignKeys[:0]
 	for _, fk := range tblInfo.ForeignKeys {
 		if fk.Name.L != fkName.L {
 			nfks = append(nfks, fk)
 		}
 	}
 	tblInfo.ForeignKeys = nfks
-
-	originalState := fkInfo.State
-	switch fkInfo.State {
-	case model.StatePublic:
-		// We just support record the foreign key, so we just make it none.
-		// public -> none
-		fkInfo.State = model.StateNone
-		ver, err = updateVersionAndTableInfo(d, t, job, tblInfo, originalState != fkInfo.State)
-		if err != nil {
-			return ver, errors.Trace(err)
-		}
-		// Finish this job.
+	ver, err = updateVersionAndTableInfo(d, t, job, tblInfo, true)
+	if err != nil {
+		return ver, errors.Trace(err)
+	}
+	// Finish this job.
+	if job.IsRollingback() {
+		job.FinishTableJob(model.JobStateRollbackDone, model.StateNone, ver, tblInfo)
+	} else {
 		job.FinishTableJob(model.JobStateDone, model.StateNone, ver, tblInfo)
-		job.SchemaState = fkInfo.State
-		return ver, nil
-	default:
-		return ver, dbterror.ErrInvalidDDLState.GenWithStackByArgs("foreign key", fkInfo.State)
 	}
+	job.SchemaState = model.StateNone
+	return ver, err
 }
 
 func allocateFKIndexID(tblInfo *model.TableInfo) int64 {

ddl/foreign_key_test.go

@@ -1513,6 +1513,24 @@ func TestAddForeignKey(t *testing.T) {
 	tbl2Info = getTableInfo(t, dom, "test", "t2")
 	require.Equal(t, 0, len(tbl2Info.ForeignKeys))
 	tk.MustGetDBError("alter table t2 drop index idx_c, add constraint fk_c foreign key (c) references t1(b)", dbterror.ErrDropIndexNeededInForeignKey)
+
+	// Test cyclical Dependencies add foreign key failed.
+	tk.MustExec("drop table if exists t1,t2")
+	tk.MustExec("create table t1 (id int key,a int, index(a));")
+	tk.MustExec("create table t2 (id int key,a int, foreign key fk(a) references t1(id) ON DELETE CASCADE);")
+	tk.MustExec("insert into t1 values (1,1);")
+	err := tk.ExecToErr("ALTER TABLE t1 ADD foreign key fk(a) references t2(id) ON DELETE CASCADE;")
+	require.Error(t, err)
+	require.Equal(t, "[ddl:1452]Cannot add or update a child row: a foreign key constraint fails (`test`.`t1`, CONSTRAINT `fk` FOREIGN KEY (`a`) REFERENCES `t2` (`id`) ON DELETE CASCADE)", err.Error())
+	tbl1Info := getTableInfo(t, dom, "test", "t1")
+	require.Equal(t, 0, len(tbl1Info.ForeignKeys))
+	referredFKs := dom.InfoSchema().GetTableReferredForeignKeys("test", "t2")
+	require.Equal(t, 0, len(referredFKs))
+	tk.MustQuery("show create table t1").Check(testkit.Rows("t1 CREATE TABLE `t1` (\n" +
+		"  `id` int(11) NOT NULL,\n" +
+		"  `a` int(11) DEFAULT NULL,\n" +
+		"  PRIMARY KEY (`id`) /*T![clustered_index] CLUSTERED */,\n" +
+		"  KEY `a` (`a`)\n) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin"))
 }
 
 func TestAddForeignKey2(t *testing.T) {