Fix: mix format crashes in umbrella projects (#230)

Skips compilation at umbrella root to avoid Mix.ProjectStack violations.
The compile task added in 9eddbeb (fixing #228) causes crashes in umbrella
projects because Mix.ProjectStack doesn't support recursive compilation
during format operations.

* Apply suggestion from @zachdaniel

* fix: replace explicit try with implicit try and remove deprecated unless

Author: matthewsinclair

lib/mix/tasks/spark.formatter.ex

@@ -10,7 +10,11 @@ if Code.ensure_loaded?(Sourceror) do
 
     @spec run(term) :: no_return
     def run(opts) do
-      Mix.Task.run("compile")
+      # Compile if safe to do so (not at umbrella root)
+      if not Mix.Project.umbrella?() do
+        Mix.Task.run("compile")
+      end
+
       {opts, []} = OptionParser.parse!(opts, strict: [check: :boolean, extensions: :string])
 
       unless opts[:extensions] do
@@ -25,8 +29,24 @@ if Code.ensure_loaded?(Sourceror) do
       locals_without_parens =
         Enum.flat_map(extensions, fn extension_mod ->
           case Code.ensure_compiled(extension_mod) do
-            {:module, _module} -> :ok
-            other -> raise "Error ensuring extension compiled #{inspect(other)}"
+            {:module, _module} ->
+              :ok
+
+            other ->
+              error_msg =
+                if Mix.Project.umbrella?() do
+                  """
+                  Error ensuring extension compiled: #{inspect(other)}
+
+                  You are running this task from an umbrella project root.
+                  Try running this task from within a sub-app directory, or compile the project first:
+                    cd apps/<your_app> && mix spark.formatter --extensions #{opts[:extensions]}
+                  """
+                else
+                  "Error ensuring extension compiled #{inspect(other)}"
+                end
+
+              raise error_msg
           end
 
           all_entity_builders_everywhere(

lib/spark/formatter.ex

@@ -58,10 +58,7 @@ if Code.ensure_loaded?(Sourceror) do
     end
 
     def format(contents, opts) do
-      Mix.Task.reenable("compile")
-      Mix.Task.reenable("loadpaths")
-      Mix.Task.run("compile")
-      Mix.Task.run("loadpaths")
+      safe_compile()
 
       config =
         :spark
@@ -100,6 +97,18 @@ if Code.ensure_loaded?(Sourceror) do
       end
     end
 
+    # Compiles the project if safe to do so.
+    # Skips compilation when running at umbrella root to avoid Mix.ProjectStack violations.
+    # See: https://github.com/elixir-lang/elixir/issues/11759
+    defp safe_compile do
+      if not Mix.Project.umbrella?() do
+        Mix.Task.reenable("compile")
+        Mix.Task.reenable("loadpaths")
+        Mix.Task.run("compile")
+        Mix.Task.run("loadpaths")
+      end
+    end
+
     defp format_resources(parsed, opts, config) do
       {_, patches} =
         Spark.CodeHelpers.prewalk(parsed, [], false, fn
@@ -305,7 +314,7 @@ if Code.ensure_loaded?(Sourceror) do
         end)
       end)
       |> Enum.concat(config[:extensions] || [])
-      |> Enum.concat(type.default_extensions() || [])
+      |> Enum.concat(safe_get_default_extensions(type))
       |> Enum.flat_map(fn extension ->
         try do
           [extension | extension.add_extensions()]
@@ -315,6 +324,21 @@ if Code.ensure_loaded?(Sourceror) do
       end)
     end
 
+    defp safe_get_default_extensions(type) do
+      type.default_extensions() || []
+    rescue
+      error ->
+        Logger.warning("""
+        Spark.Formatter: Could not load default_extensions for #{inspect(type)}.
+        This can happen in umbrella projects when running format from the root.
+        Try running format from within the sub-app, or compile first with: mix compile
+
+        Error: #{inspect(error)}
+        """)
+
+        []
+    end
+
     defp opts_without_plugin(opts) do
       Keyword.update(opts, :plugins, [], &(&1 -- [__MODULE__]))
     end

test/formatter_test.exs

@@ -97,4 +97,49 @@ defmodule Spark.Test.FormatterTest do
            end
            """
   end
+
+  test "it works in umbrella projects without crashing", %{opts: opts} do
+    config_contact(section_order: [:address, :personal_details])
+
+    # Mock Mix.Project.umbrella?() to return true
+    # We can't easily mock this, but we can at least verify the formatter
+    # doesn't crash when umbrella? returns true by testing the safe_compile function
+    # indirectly through normal formatting (which should work regardless)
+
+    # This test verifies that formatting works even if compilation is skipped
+    result =
+      Spark.Formatter.format(
+        """
+        defmodule IncredibleHulk do
+          use Spark.Test.Contact
+
+          personal_details do
+            first_name("Incredible")
+            last_name("Hulk")
+          end
+
+          address do
+            street("Avenger Lane")
+          end
+        end
+        """,
+        opts
+      )
+
+    # Should format successfully without crashing
+    assert result == """
+           defmodule IncredibleHulk do
+             use Spark.Test.Contact
+
+             address do
+               street "Avenger Lane"
+             end
+
+             personal_details do
+               first_name "Incredible"
+               last_name "Hulk"
+             end
+           end
+           """
+  end
 end