Merge pull request #10249 from jlhawn/distribution_version_header_10247

Split API Version header when checking for v2

registry/endpoint.go

@@ -231,10 +231,13 @@ func (e *Endpoint) pingV2() (RegistryInfo, error) {
 	// Ensure it supports the v2 Registry API.
 	var supportsV2 bool
 
-	for _, versionName := range resp.Header[http.CanonicalHeaderKey("Docker-Distribution-API-Version")] {
-		if versionName == "registry/2.0" {
-			supportsV2 = true
-			break
+HeaderLoop:
+	for _, supportedVersions := range resp.Header[http.CanonicalHeaderKey("Docker-Distribution-API-Version")] {
+		for _, versionName := range strings.Fields(supportedVersions) {
+			if versionName == "registry/2.0" {
+				supportsV2 = true
+				break HeaderLoop
+			}
 		}
 	}
 

registry/endpoint_test.go

@@ -42,7 +42,9 @@ func TestValidateEndpointAmbiguousAPIVersion(t *testing.T) {
 	})
 
 	requireBasicAuthHandlerV2 := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Add("Docker-Distribution-API-Version", "registry/2.0")
+		// This mock server supports v2.0, v2.1, v42.0, and v100.0
+		w.Header().Add("Docker-Distribution-API-Version", "registry/100.0 registry/42.0")
+		w.Header().Add("Docker-Distribution-API-Version", "registry/2.0 registry/2.1")
 		requireBasicAuthHandler.ServeHTTP(w, r)
 	})