Copy store options to sessions instead of referencing them.

Fixes GH-8

store.go

@@ -73,7 +73,8 @@ func (s *CookieStore) Get(r *http.Request, name string) (*Session, error) {
 // decoded session after the first call.
 func (s *CookieStore) New(r *http.Request, name string) (*Session, error) {
 	session := NewSession(s, name)
-	session.Options = &(*s.Options)
+	opts := *s.Options
+	session.Options = &opts
 	session.IsNew = true
 	var err error
 	if c, errCookie := r.Cookie(name); errCookie == nil {
@@ -148,7 +149,8 @@ func (s *FilesystemStore) Get(r *http.Request, name string) (*Session, error) {
 // See CookieStore.New().
 func (s *FilesystemStore) New(r *http.Request, name string) (*Session, error) {
 	session := NewSession(s, name)
-	session.Options = &(*s.Options)
+	opts := *s.Options
+	session.Options = &opts
 	session.IsNew = true
 	var err error
 	if c, errCookie := r.Cookie(name); errCookie == nil {

store_test.go

@@ -0,0 +1,48 @@
+package sessions
+
+import (
+	"net/http"
+	"testing"
+)
+
+// Test for GH-8 for CookieStore
+func TestGH8CookieStore(t *testing.T) {
+	originalPath := "/"
+	store := NewCookieStore()
+	store.Options.Path = originalPath
+	req, err := http.NewRequest("GET", "http://www.example.com", nil)
+	if err != nil {
+		t.Fatal("failed to create request", err)
+	}
+
+	session, err := store.New(req, "hello")
+	if err != nil {
+		t.Fatal("failed to create session", err)
+	}
+
+	store.Options.Path = "/foo"
+	if session.Options.Path != originalPath {
+		t.Fatalf("bad session path: got %q, want %q", session.Options.Path, originalPath)
+	}
+}
+
+// Test for GH-8 for FilesystemStore
+func TestGH8FilesystemStore(t *testing.T) {
+	originalPath := "/"
+	store := NewFilesystemStore("")
+	store.Options.Path = originalPath
+	req, err := http.NewRequest("GET", "http://www.example.com", nil)
+	if err != nil {
+		t.Fatal("failed to create request", err)
+	}
+
+	session, err := store.New(req, "hello")
+	if err != nil {
+		t.Fatal("failed to create session", err)
+	}
+
+	store.Options.Path = "/foo"
+	if session.Options.Path != originalPath {
+		t.Fatalf("bad session path: got %q, want %q", session.Options.Path, originalPath)
+	}
+}