Merge pull request #332 from alexarchambault/topic/fix

Fix plugin handling

cache/src/main/scala/coursier/Cache.scala

@@ -1,7 +1,7 @@
 package coursier
 
 import java.math.BigInteger
-import java.net.{ HttpURLConnection, URL, URLConnection, URLStreamHandler }
+import java.net.{ HttpURLConnection, URL, URLConnection, URLStreamHandler, URLStreamHandlerFactory }
 import java.nio.channels.{ OverlappingFileLockException, FileLock }
 import java.nio.file.{ StandardCopyOption, Files => NioFiles }
 import java.security.MessageDigest
@@ -243,21 +243,24 @@ object Cache {
     Option(handlerClsCache.get(protocol)) match {
       case None =>
         val clsName = s"coursier.cache.protocol.${protocol.capitalize}Handler"
-        val clsOpt =
-          try Some(Thread.currentThread().getContextClassLoader.loadClass(clsName))
+        def clsOpt(loader: ClassLoader) =
+          try Some(loader.loadClass(clsName))
           catch {
             case _: ClassNotFoundException =>
               None
           }
 
+        val clsOpt0 = clsOpt(Thread.currentThread().getContextClassLoader)
+          .orElse(clsOpt(getClass.getClassLoader))
+
         def printError(e: Exception): Unit =
           scala.Console.err.println(
             s"Cannot instantiate $clsName: $e${Option(e.getMessage).fold("")(" ("+_+")")}"
           )
 
-        val handlerOpt = clsOpt.flatMap {
+        val handlerFactoryOpt = clsOpt0.flatMap {
           cls =>
-            try Some(cls.newInstance().asInstanceOf[URLStreamHandler])
+            try Some(cls.newInstance().asInstanceOf[URLStreamHandlerFactory])
             catch {
               case e: InstantiationException =>
                 printError(e)
@@ -271,6 +274,18 @@ object Cache {
             }
         }
 
+        val handlerOpt = handlerFactoryOpt.flatMap {
+          factory =>
+            try Some(factory.createURLStreamHandler(protocol))
+            catch {
+              case NonFatal(e) =>
+                scala.Console.err.println(
+                  s"Cannot get handler for $protocol from $clsName: $e${Option(e.getMessage).fold("")(" ("+_+")")}"
+                )
+                None
+            }
+        }
+
         val prevOpt = Option(handlerClsCache.putIfAbsent(protocol, handlerOpt))
         prevOpt.getOrElse(handlerOpt)
 

tests/jvm/src/test/scala/coursier/cache/protocol/TestprotocolHandler.scala

@@ -1,19 +1,22 @@
 package coursier.cache.protocol
 
-import java.net.{ URL, URLConnection, URLStreamHandler }
+import java.net.{ URL, URLConnection, URLStreamHandler, URLStreamHandlerFactory }
 
-class TestprotocolHandler extends URLStreamHandler {
-  protected def openConnection(url: URL): URLConnection = {
-    val resPath = "/test-repo/http/abc.com" + url.getPath
-    val resURLOpt = Option(getClass.getResource(resPath))
+class TestprotocolHandler extends URLStreamHandlerFactory {
 
-    resURLOpt match {
-      case None =>
-        new URLConnection(url) {
-          def connect() = throw new NoSuchElementException(s"Resource $resPath")
-        }
-      case Some(resURL) =>
-        resURL.openConnection()
+  def createURLStreamHandler(protocol: String): URLStreamHandler = new URLStreamHandler {
+    protected def openConnection(url: URL): URLConnection = {
+      val resPath = "/test-repo/http/abc.com" + url.getPath
+      val resURLOpt = Option(getClass.getResource(resPath))
+
+      resURLOpt match {
+        case None =>
+          new URLConnection(url) {
+            def connect() = throw new NoSuchElementException(s"Resource $resPath")
+          }
+        case Some(resURL) =>
+          resURL.openConnection()
+      }
     }
   }
 }