Use existing nonzero values in autoincr fields instead of overwriting with new autoincr value

modl_test.go

@@ -365,6 +365,50 @@ func TestColumnProps(t *testing.T) {
 	}
 }
 
+func TestAutoIncrOverride(t *testing.T) {
+	dbmap := newDbMap()
+	type T struct {
+		A  string
+		ID int
+		B  string
+	}
+	//dbmap.TraceOn("", log.New(os.Stdout, "modltest: ", log.Lmicroseconds))
+	dbmap.AddTable(T{}).SetKeys(true, "ID")
+
+	err := dbmap.CreateTables()
+	if err != nil {
+		panic(err)
+	}
+	defer dbmap.Cleanup()
+
+	// Insert with a zero pkey.
+	t0 := &T{ID: 0}
+	_insert(dbmap, t0)
+	t1 := T{}
+	MustGet(dbmap, &t1, t0.ID)
+	if t1.ID != t0.ID {
+		t.Errorf("got t1.ID == %d, want %d", t1.ID, t0.ID)
+	}
+
+	// Insert with an overridden nonzero pkey.
+	t2 := &T{ID: 123}
+	_insert(dbmap, t2)
+	t3 := T{}
+	MustGet(dbmap, &t3, 123)
+	if t3.ID != 123 {
+		t.Errorf("got t3.ID == %d, want %d", t3.ID, 123)
+	}
+
+	// Insert with a zero pkey.
+	t4 := &T{ID: 0}
+	_insert(dbmap, t4)
+	t5 := T{}
+	MustGet(dbmap, &t5, t4.ID)
+	if t5.ID != t4.ID {
+		t.Errorf("got t5.ID == %d, want %d", t5.ID, t4.ID)
+	}
+}
+
 func TestRawSelect(t *testing.T) {
 	dbmap := initDbMap()
 	defer dbmap.Cleanup()
@@ -592,9 +636,8 @@ func TestWithStringPk(t *testing.T) {
 	defer dbmap.Cleanup()
 
 	row := &WithStringPk{"1", "foo"}
-	err = dbmap.Insert(row)
-	if err == nil {
-		t.Errorf("Expected error when inserting into table w/non Int PK and autoincr set true")
+	if err := dbmap.Insert(row); err != nil {
+		t.Error(err)
 	}
 }
 

tablemap.go

@@ -18,7 +18,6 @@ type TableMap struct {
 	Columns    []*ColumnMap
 	gotype     reflect.Type
 	version    *ColumnMap
-	insertPlan bindPlan
 	updatePlan bindPlan
 	deletePlan bindPlan
 	getPlan    bindPlan
@@ -32,13 +31,17 @@ type TableMap struct {
 	CanPostUpdate bool
 	CanPreDelete  bool
 	CanPostDelete bool
+
+	insertPlan         *bindPlan
+	insertAutoIncrPlan *bindPlan
 }
 
 // ResetSql removes cached insert/update/select/delete SQL strings
 // associated with this TableMap.  Call this if you've modified
 // any column names or the table name itself.
 func (t *TableMap) ResetSql() {
-	t.insertPlan = bindPlan{}
+	t.insertPlan = nil
+	t.insertAutoIncrPlan = nil
 	t.updatePlan = bindPlan{}
 	t.deletePlan = bindPlan{}
 	t.getPlan = bindPlan{}
@@ -234,10 +237,37 @@ func (t *TableMap) bindUpdate(elem reflect.Value) bindInstance {
 	return plan.createBindInstance(elem)
 }
 
+func isZeroVal(v reflect.Value) bool {
+	return v.Interface() == reflect.Zero(v.Type()).Interface()
+}
+
 func (t *TableMap) bindInsert(elem reflect.Value) bindInstance {
-	plan := t.insertPlan
-	if plan.query == "" {
-		plan.autoIncrIdx = -1
+	// There are 2 possible insert plans: (1) if the autoincr field is
+	// empty, then use a plan that inserts the AutoIncrBindValue; or
+	// (2) if the autoincr field is not empty, use a plan that inserts
+	// the row with the actual field value.
+
+	insertsAutoIncrVal := false
+	for _, col := range t.Keys {
+		if col.isAutoIncr && isZeroVal(elem.FieldByName(col.fieldName)) {
+			// This stmt needs to insert an auto-incremented value.
+			insertsAutoIncrVal = true
+			break
+		}
+	}
+
+	var plan *bindPlan
+	if insertsAutoIncrVal {
+		plan = t.insertAutoIncrPlan
+	} else {
+		plan = t.insertPlan
+	}
+
+	if plan == nil {
+		plan = &bindPlan{}
+		if !insertsAutoIncrVal {
+			plan.autoIncrIdx = -1
+		}
 
 		s := bytes.Buffer{}
 		s2 := bytes.Buffer{}
@@ -255,7 +285,7 @@ func (t *TableMap) bindInsert(elem reflect.Value) bindInstance {
 				}
 				s.WriteString(t.dbmap.Dialect.QuoteField(col.ColumnName))
 
-				if col.isAutoIncr {
+				if col.isAutoIncr && isZeroVal(elem.FieldByName(col.fieldName)) {
 					s2.WriteString(t.dbmap.Dialect.AutoIncrBindValue())
 					plan.autoIncrIdx = y
 				} else {
@@ -282,7 +312,12 @@ func (t *TableMap) bindInsert(elem reflect.Value) bindInstance {
 		s.WriteString(";")
 
 		plan.query = s.String()
-		t.insertPlan = plan
+
+		if insertsAutoIncrVal {
+			t.insertAutoIncrPlan = plan
+		} else {
+			t.insertPlan = plan
+		}
 	}
 
 	return plan.createBindInstance(elem)