ddl: fix recover table by JobID bug when JobID is set to 0 tidb-server panic

pkg/executor/ddl.go

@@ -393,10 +393,11 @@ func (e *DDLExec) executeRecoverTable(s *ast.RecoverTableStmt) error {
 	var job *model.Job
 	var err error
 	var tblInfo *model.TableInfo
-	if s.JobID != 0 {
-		job, tblInfo, err = e.getRecoverTableByJobID(s, dom)
-	} else {
+	// Let check table first. Related isssue #46296.
+	if s.Table != nil {
 		job, tblInfo, err = e.getRecoverTableByTableName(s.Table)
+	} else {
+		job, tblInfo, err = e.getRecoverTableByJobID(s, dom)
 	}
 	if err != nil {
 		return err

pkg/executor/recover_test.go

@@ -92,6 +92,11 @@ func TestRecoverTable(t *testing.T) {
 	err := tk.ExecToErr(fmt.Sprintf("recover table by job %d", 10000000))
 	require.Error(t, err)
 
+	// recover table by zero JobID.
+	// related issue: https://github.com/pingcap/tidb/issues/46296
+	err = tk.ExecToErr(fmt.Sprintf("recover table by job %d", 0))
+	require.Error(t, err)
+
 	// Disable GC by manual first, then after recover table, the GC enable status should also be disabled.
 	require.NoError(t, gcutil.DisableGC(tk.Session()))
 

pkg/parser/ast/ddl.go

@@ -4381,16 +4381,16 @@ type RecoverTableStmt struct {
 // Restore implements Node interface.
 func (n *RecoverTableStmt) Restore(ctx *format.RestoreCtx) error {
 	ctx.WriteKeyWord("RECOVER TABLE ")
-	if n.JobID != 0 {
-		ctx.WriteKeyWord("BY JOB ")
-		ctx.WritePlainf("%d", n.JobID)
-	} else {
+	if n.Table != nil {
 		if err := n.Table.Restore(ctx); err != nil {
 			return errors.Annotate(err, "An error occurred while splicing RecoverTableStmt Table")
 		}
 		if n.JobNum > 0 {
 			ctx.WritePlainf(" %d", n.JobNum)
 		}
+	} else {
+		ctx.WriteKeyWord("BY JOB ")
+		ctx.WritePlainf("%d", n.JobID)
 	}
 	return nil
 }