Introduce Unsafe method on Queryx

It enables local control over `unsafe` mode for .Bind methods of `Queryx` and iterators
spawn by it.

iterx.go

@@ -13,7 +13,7 @@ import (
 	"github.com/scylladb/go-reflectx"
 )
 
-// DefaultUnsafe enables the behavior of forcing the iterator to ignore
+// DefaultUnsafe enables the behavior of forcing queries and iterators to ignore
 // missing fields for all queries. See Unsafe below for more information.
 var DefaultUnsafe bool
 

iterx_test.go

@@ -484,12 +484,8 @@ func TestIterxUnsafe(t *testing.T) {
 	})
 
 	t.Run("select default unsafe", func(t *testing.T) {
-		gocqlx.DefaultUnsafe = true
-		defer func() {
-			gocqlx.DefaultUnsafe = false
-		}()
 		var v []UnsafeTable
-		err := session.Query(stmt, nil).Iter().Select(&v)
+		err := session.Query(stmt, nil).Unsafe().Iter().Select(&v)
 		if err != nil {
 			t.Fatal("Select() failed:", err)
 		}

queryx.go

@@ -95,6 +95,7 @@ type Queryx struct {
 	Mapper *reflectx.Mapper
 	*gocql.Query
 	Names  []string
+	unsafe bool
 }
 
 // Query creates a new Queryx from gocql.Query using a default mapper.
@@ -106,6 +107,7 @@ func Query(q *gocql.Query, names []string) *Queryx {
 		Names:  names,
 		Mapper: DefaultMapper,
 		tr:     DefaultBindTransformer,
+		unsafe: DefaultUnsafe,
 	}
 }
 
@@ -209,7 +211,7 @@ func (q *Queryx) bindMapArgs(arg map[string]interface{}) ([]interface{}, error)
 // Bind sets query arguments of query. This can also be used to rebind new query arguments
 // to an existing query instance.
 func (q *Queryx) Bind(v ...interface{}) *Queryx {
-	q.Query.Bind(udtWrapSlice(q.Mapper, DefaultUnsafe, v)...)
+	q.Query.Bind(udtWrapSlice(q.Mapper, q.unsafe, v)...)
 	return q
 }
 
@@ -342,6 +344,14 @@ func (q *Queryx) Iter() *Iterx {
 	return &Iterx{
 		Iter:   q.Query.Iter(),
 		Mapper: q.Mapper,
-		unsafe: DefaultUnsafe,
+		unsafe: q.unsafe,
 	}
 }
+
+// Unsafe forces the query and iterators to ignore missing fields. By default when scanning
+// a struct if result row has a column that cannot be mapped to any destination
+// field an error is reported. With unsafe such columns are ignored.
+func (q *Queryx) Unsafe() *Queryx {
+	q.unsafe = true
+	return q
+}

session.go

@@ -51,6 +51,7 @@ func (s Session) ContextQuery(ctx context.Context, stmt string, names []string)
 		Names:  names,
 		Mapper: s.Mapper,
 		tr:     DefaultBindTransformer,
+		unsafe: DefaultUnsafe,
 	}
 }
 
@@ -65,6 +66,7 @@ func (s Session) Query(stmt string, names []string) *Queryx {
 		Names:  names,
 		Mapper: s.Mapper,
 		tr:     DefaultBindTransformer,
+		unsafe: DefaultUnsafe,
 	}
 }