Merge pull request #4285 from tonistiigi/double-merge-edge-fix

solver: fix issue with double merged edges

solver/edge.go

@@ -64,6 +64,7 @@ type edge struct {
  hasActiveOutgoing bool
 
  releaserCount int
+ owner *edge
  keysDidChange bool
  index *edgeIndex
 
@@ -116,10 +117,12 @@ type edgeRequest struct {
  currentKeys int
 }
 
-// incrementReferenceCount increases the number of times release needs to be
+// takeOwnership increases the number of times release needs to be
 // called to release the edge. Called on merging edges.
-func (e *edge) incrementReferenceCount() {
- e.releaserCount++
+func (e *edge) takeOwnership(old *edge) {
+ e.releaserCount += old.releaserCount + 1
+ old.owner = e
+ old.releaseResult()
 }
 
 // release releases the edge resources
@@ -128,6 +131,10 @@ func (e *edge) release() {
  e.releaserCount--
  return
  }
+ e.releaseResult()
+}
+
+func (e *edge) releaseResult() {
  e.index.Release(e)
  if e.result != nil {
  go e.result.Release(context.TODO())

solver/jobs.go

@@ -141,6 +141,9 @@ func (s *state) getEdge(index Index) *edge {
  s.mu.Lock()
  defer s.mu.Unlock()
  if e, ok := s.edges[index]; ok {
+ for e.owner != nil {
+ e = e.owner
+ }
  return e
  }
 
@@ -153,19 +156,22 @@ func (s *state) getEdge(index Index) *edge {
  return e
 }
 
-func (s *state) setEdge(index Index, newEdge *edge) {
+func (s *state) setEdge(index Index, targetEdge *edge) {
  s.mu.Lock()
  defer s.mu.Unlock()
  e, ok := s.edges[index]
  if ok {
- if e == newEdge {
+ for e.owner != nil {
+ e = e.owner
+ }
+ if e == targetEdge {
  return
  }
- e.release()
+ } else {
+ e = newEdge(Edge{Index: index, Vertex: s.vtx}, s.op, s.index)
+ s.edges[index] = e
  }
-
- newEdge.incrementReferenceCount()
- s.edges[index] = newEdge
+ targetEdge.takeOwnership(e)
 }
 
 func (s *state) combinedCacheManager() CacheManager {
@@ -186,6 +192,9 @@ func (s *state) combinedCacheManager() CacheManager {
 
 func (s *state) Release() {
  for _, e := range s.edges {
+ for e.owner != nil {
+ e = e.owner
+ }
  e.release()
  }
  if s.op != nil {