[master] Auto-update dependencies (#252)

Produced via:
  `./hack/update-deps.sh --upgrade && ./hack/update-codegen.sh`
/assign n3wscott vagababov
/cc n3wscott vagababov

Gopkg.lock

@@ -966,7 +966,7 @@
 
 [[projects]]
   branch = "master"
-  digest = "1:0dad40d47b86a73d04830e077504d31f508d6e13b802ca53521a5d5d0e4fa4ed"
+  digest = "1:518e5e7cb6aa149f3ea33bbfdfd367e4ab413d3405e33d85e09ac1f9b7a74c1f"
   name = "knative.dev/pkg"
   packages = [
     "apis",
@@ -986,7 +986,7 @@
     "reconciler",
   ]
   pruneopts = "T"
-  revision = "9d7c06b6ab647bcb2e414e90d740b26915917cbf"
+  revision = "9320e44d1bf75c228b98b30cedcb98bb6e1424ee"
 
 [[projects]]
   branch = "master"
@@ -997,7 +997,7 @@
     "tools/dep-collector",
   ]
   pruneopts = "UT"
-  revision = "2f62d241ccc085436d060ad5f6764333a50ccf49"
+  revision = "000a646b850e6f86e3360e7d376edd9c545d31c1"
 
 [[projects]]
   digest = "1:8730e0150dfb2b7e173890c8b9868e7a273082ef8e39f4940e3506a481cf895c"

vendor/knative.dev/pkg/apis/duck/cached.go

@@ -29,7 +29,7 @@ type CachedInformerFactory struct {
 	Delegate InformerFactory
 
 	m     sync.Mutex
-	cache map[schema.GroupVersionResource]*result
+	cache map[schema.GroupVersionResource]*informerCache
 }
 
 // Check that CachedInformerFactory implements InformerFactory.
@@ -38,27 +38,41 @@ var _ InformerFactory = (*CachedInformerFactory)(nil)
 // Get implements InformerFactory.
 func (cif *CachedInformerFactory) Get(gvr schema.GroupVersionResource) (cache.SharedIndexInformer, cache.GenericLister, error) {
 	cif.m.Lock()
+
 	if cif.cache == nil {
-		cif.cache = make(map[schema.GroupVersionResource]*result)
+		cif.cache = make(map[schema.GroupVersionResource]*informerCache)
 	}
-	elt, ok := cif.cache[gvr]
+
+	ic, ok := cif.cache[gvr]
 	if !ok {
-		elt = &result{}
-		elt.init = func() {
-			elt.inf, elt.lister, elt.err = cif.Delegate.Get(gvr)
+		ic = &informerCache{}
+		ic.init = func() {
+			ic.Lock()
+			defer ic.Unlock()
+
+			// double-checked lock to ensure we call the Delegate
+			// only once even if multiple goroutines end up inside
+			// init() simultaneously
+			if ic.hasInformer() {
+				return
+			}
+
+			ic.inf, ic.lister, ic.err = cif.Delegate.Get(gvr)
 		}
-		cif.cache[gvr] = elt
+		cif.cache[gvr] = ic
 	}
+
 	// If this were done via "defer", then TestDifferentGVRs will fail.
 	cif.m.Unlock()
 
 	// The call to the delegate could be slow because it syncs informers, so do
 	// this outside of the main lock.
-	return elt.Get()
+	return ic.Get()
 }
 
-type result struct {
-	sync.Once
+type informerCache struct {
+	sync.RWMutex
+
 	init func()
 
 	inf    cache.SharedIndexInformer
@@ -66,7 +80,21 @@ type result struct {
 	err    error
 }
 
-func (t *result) Get() (cache.SharedIndexInformer, cache.GenericLister, error) {
-	t.Do(t.init)
-	return t.inf, t.lister, t.err
+// Get returns the cached informer. If it does not yet exist, we first try to
+// acquire one by executing the cache's init function.
+func (ic *informerCache) Get() (cache.SharedIndexInformer, cache.GenericLister, error) {
+	if !ic.initialized() {
+		ic.init()
+	}
+	return ic.inf, ic.lister, ic.err
+}
+
+func (ic *informerCache) initialized() bool {
+	ic.RLock()
+	defer ic.RUnlock()
+	return ic.hasInformer()
+}
+
+func (ic *informerCache) hasInformer() bool {
+	return ic.inf != nil && ic.lister != nil
 }