diff --git a/pkgs/build-support/fetchzip/default.nix b/pkgs/build-support/fetchzip/default.nix
index 7c6e16a05892..12fb69ba8efd 100644
--- a/pkgs/build-support/fetchzip/default.nix
+++ b/pkgs/build-support/fetchzip/default.nix
@@ -13,9 +13,7 @@
 , ... } @ args:
 
 fetchurl ({
-  # Remove the extension, because otherwise unpackPhase will get
-  # confused. FIXME: fix unpackPhase.
-  name = args.name or lib.removeSuffix ".zip" (lib.removeSuffix ".tar.gz" (baseNameOf url));
+  name = args.name or (baseNameOf url);
 
   recursiveHash = true;
 
diff --git a/pkgs/stdenv/generic/setup.sh b/pkgs/stdenv/generic/setup.sh
index 286e9e019b1d..c3ebc3e9b5f0 100644
--- a/pkgs/stdenv/generic/setup.sh
+++ b/pkgs/stdenv/generic/setup.sh
@@ -475,32 +475,36 @@ unpackFile() {
 
     header "unpacking source archive $curSrc" 3
 
-    case "$curSrc" in
-        *.tar.xz | *.tar.lzma)
-            # Don't rely on tar knowing about .xz.
-            xz -d < $curSrc | tar xf -
-            ;;
-        *.tar | *.tar.* | *.tgz | *.tbz2)
-            # GNU tar can automatically select the decompression method
-            # (info "(tar) gzip").
-            tar xf $curSrc
-            ;;
-        *.zip)
-            unzip -qq $curSrc
-            ;;
-        *)
-            if [ -d "$curSrc" ]; then
-                stripHash $curSrc
-                cp -prd --no-preserve=timestamps $curSrc $strippedName
-            else
+    if [ -d "$curSrc" ]; then
+
+        stripHash $curSrc
+        cp -prd --no-preserve=timestamps $curSrc $strippedName
+
+    else
+
+        case "$curSrc" in
+            *.tar.xz | *.tar.lzma)
+                # Don't rely on tar knowing about .xz.
+                xz -d < $curSrc | tar xf -
+                ;;
+            *.tar | *.tar.* | *.tgz | *.tbz2)
+                # GNU tar can automatically select the decompression method
+                # (info "(tar) gzip").
+                tar xf $curSrc
+                ;;
+            *.zip)
+                unzip -qq $curSrc
+                ;;
+            *)
                 if [ -z "$unpackCmd" ]; then
                     echo "source archive $curSrc has unknown type"
                     exit 1
                 fi
                 runSingleHook unpackCmd
-            fi
-            ;;
-    esac
+                ;;
+        esac
+
+    fi
 
     stopNest
 }