Address follow-up review of 7ae97db

- Filter unparseable versions in Linker.resolve_nested_version before
  version_gt? to prevent Version.parse! crash on lenient npm versions
- Restore rescue _ in Exec.find_in_packages with explanatory comment
  (ErlangError was nearly as broad and less honest about intent)
- Update Cache.ensure/5 docstring to document :missing_optional return
- Fix dead || branch in FileSize.by_extension (Path.extname returns
  "" not nil — the || "(none)" could never trigger)
- Remove dead {:error, :cycle} branch in DepSort.install_order
  (sort/1 always returns {:ok, order} for acyclic graphs)

Author: dannote

lib/npm/cache.ex

@@ -31,7 +31,8 @@ defmodule NPM.Cache do
   Ensure a package version is in the cache.
 
   Downloads and extracts the tarball if not already cached.
-  Returns `{:ok, cache_path}` or `{:error, reason}`.
+  Returns `{:ok, cache_path}`, `{:ok, :missing_optional}` when an
+  optional package fails to fetch, or `{:error, reason}`.
   """
   @spec ensure(String.t(), String.t(), String.t(), String.t(), keyword()) ::
           {:ok, String.t()} | {:ok, :missing_optional} | {:error, term()}

lib/npm/dep_sort.ex

@@ -21,10 +21,8 @@ defmodule NPM.DepSort do
   """
   @spec install_order(map()) :: [String.t()]
   def install_order(adj) do
-    case sort(adj) do
-      {:ok, order} -> Enum.reverse(order)
-      {:error, :cycle} -> Map.keys(adj) |> Enum.sort()
-    end
+    {:ok, order} = sort(adj)
+    Enum.reverse(order)
   end
 
   @doc """

lib/npm/exec.ex

@@ -98,7 +98,8 @@ defmodule NPM.Exec do
         {:error, :not_found}
     end
   rescue
-    ErlangError -> {:error, :not_found}
+    # JSON decode, missing keys, or unexpected package.json shape
+    _ -> {:error, :not_found}
   end
 
   defp resolve_bin(%{"bin" => bin}, _command, nm_dir) when is_binary(bin) do

lib/npm/file_size.ex

@@ -37,7 +37,12 @@ defmodule NPM.FileSize do
   @spec by_extension(String.t()) :: %{String.t() => non_neg_integer()}
   def by_extension(package_dir) do
     analyze(package_dir)
-    |> Enum.group_by(fn %{path: path} -> Path.extname(path) || "(none)" end)
+    |> Enum.group_by(fn %{path: path} ->
+      case Path.extname(path) do
+        "" -> "(none)"
+        ext -> ext
+      end
+    end)
     |> Map.new(fn {ext, files} ->
       {ext, files |> Enum.map(& &1.size) |> Enum.sum()}
     end)

lib/npm/linker.ex

@@ -251,7 +251,9 @@ defmodule NPM.Linker do
       {:ok, packument} ->
         packument.versions
         |> Map.keys()
-        |> Enum.filter(&version_matches?(&1, range))
+        |> Enum.filter(fn v ->
+          version_matches?(v, range) and match?({:ok, _}, Version.parse(v))
+        end)
         |> Enum.sort(&version_gt?/2)
         |> List.first()