Bugfix for chained Where() (doug-martin#24)

* Added test for chained Where() calls with expression overwriting

* Fixed bug with chained Where with expression overwriting

dataset_select_test.go

@@ -299,6 +299,31 @@ func (me *datasetTest) TestWhere() {
  assert.Equal(t, sql, `SELECT * FROM "test" WHERE ("a" IN (SELECT "id" FROM "test2"))`)
 }
 
+func (me *datasetTest) TestWhereChain() {
+ t := me.T()
+ ds1 := From("test").Where(
+ I("x").Eq(0),
+ I("y").Eq(1),
+ )
+
+ ds2 := ds1.Where(
+ I("z").Eq(2),
+ )
+
+ a := ds2.Where(
+ I("a").Eq("A"),
+ )
+ b := ds2.Where(
+ I("b").Eq("B"),
+ )
+ sql, _, err := a.ToSql()
+ assert.NoError(t, err)
+ assert.Equal(t, sql, `SELECT * FROM "test" WHERE (("x" = 0) AND ("y" = 1) AND ("z" = 2) AND ("a" = 'A'))`)
+ sql, _, err = b.ToSql()
+ assert.NoError(t, err)
+ assert.Equal(t, sql, `SELECT * FROM "test" WHERE (("x" = 0) AND ("y" = 1) AND ("z" = 2) AND ("b" = 'B'))`)
+}
+
 func (me *datasetTest) TestClearWhere() {
  t := me.T()
  ds1 := From("test")

expressions.go

@@ -150,7 +150,8 @@ func (me expressionList) Expressions() []Expression {
 func (me expressionList) Append(expressions ...Expression) ExpressionList {
  ret := new(expressionList)
  ret.operator = me.operator
- exps := me.expressions
+ exps := make([]Expression, len(me.expressions))
+ copy(exps, me.expressions)
  for _, exp := range expressions {
  exps = append(exps, exp)
  }