diff --git a/pkgs/build-support/fetchzip/default.nix b/pkgs/build-support/fetchzip/default.nix
index a1744b48deb9..d2f3bb48bbc2 100644
--- a/pkgs/build-support/fetchzip/default.nix
+++ b/pkgs/build-support/fetchzip/default.nix
@@ -45,16 +45,17 @@
     '' else ''
       mv "$unpackDir" "$out"
     '')
-    + extraPostFetch
-    # Remove write permissions for files unpacked with write bits set
-    # Fixes https://github.com/NixOS/nixpkgs/issues/38649
-    #
-    # However, we should (for the moment) retain write permission on the directory
-    # itself, to avoid tickling https://github.com/NixOS/nix/issues/4295 in
-    # single-user Nix installations. This is because in sandbox mode we'll try to
-    # move the path, and if we don't have write permissions on the directory,
-    # then we can't update the ".." entry.
     + ''
+      ${extraPostFetch}
+
+      # Remove write permissions for files unpacked with write bits set
+      # Fixes https://github.com/NixOS/nixpkgs/issues/38649
+      #
+      # However, we should (for the moment) retain write permission on the directory
+      # itself, to avoid tickling https://github.com/NixOS/nix/issues/4295 in
+      # single-user Nix installations. This is because in sandbox mode we'll try to
+      # move the path, and if we don't have write permissions on the directory,
+      # then we can't update the ".." entry.
       chmod -R a-w "$out"
       chmod u+w "$out"
     '';