Prevent (caught) panic on login (#11590) (#11598)

Backport #11590

Unfortunately when the virtual session is released it requires that the
real session does not exist. This worked fine when sessions were only
saved at the end of request/response cycle however, now sessions are
saved proactively this does not hold.

The result is a caught panic in the logs during every log-in.  This
panic has no significant side-effects but should not occur.

This PR marks the virtual session as released when released and updates
it if the same session is released again.

Signed-off-by: Andrew Thornton <art27@cantab.net>

diff --git a/modules/session/virtual.go b/modules/session/virtual.go
index 027960a2896968944b330d1210c3d05dc148290e..967192016740dfe84830b4814d0c13fc63bc210c 100644 (file)
--- a/modules/session/virtual.go
+++ b/modules/session/virtual.go
@@ -107,10 +107,11 @@ func init() {
 
 // VirtualStore represents a virtual session store implementation.
 type VirtualStore struct {
-       p    *VirtualSessionProvider
-       sid  string
-       lock sync.RWMutex
-       data map[interface{}]interface{}
+       p        *VirtualSessionProvider
+       sid      string
+       lock     sync.RWMutex
+       data     map[interface{}]interface{}
+       released bool
 }
 
 // NewVirtualStore creates and returns a virtual session store.
@@ -164,7 +165,7 @@ func (s *VirtualStore) Release() error {
                // Now ensure that we don't exist!
                realProvider := s.p.provider
 
-               if realProvider.Exist(s.sid) {
+               if !s.released && realProvider.Exist(s.sid) {
                        // This is an error!
                        return fmt.Errorf("new sid '%s' already exists", s.sid)
                }
@@ -172,12 +173,19 @@ func (s *VirtualStore) Release() error {
                if err != nil {
                        return err
                }
+               if err := realStore.Flush(); err != nil {
+                       return err
+               }
                for key, value := range s.data {
                        if err := realStore.Set(key, value); err != nil {
                                return err
                        }
                }
-               return realStore.Release()
+               err = realStore.Release()
+               if err == nil {
+                       s.released = true
+               }
+               return err
        }
        return nil
 }