Handle compilation exiting

apps/common/lib/elixir/features.ex

@@ -10,4 +10,8 @@ defmodule Elixir.Features do
   def config_reader? do
     Version.match?(System.version(), ">= 1.11.0")
   end
+
+  def after_verify? do
+    Version.match?(System.version(), ">= 1.14.0")
+  end
 end

apps/remote_control/lib/lexical/remote_control/build/document.ex

@@ -1,11 +1,23 @@
 defmodule Lexical.RemoteControl.Build.Document do
   alias Lexical.Document
+  alias Lexical.RemoteControl.Build
   alias Lexical.RemoteControl.Build.Document.Compilers
+  alias Lexical.RemoteControl.Build.Isolation
 
   @compilers [Compilers.Config, Compilers.Elixir, Compilers.EEx, Compilers.HEEx, Compilers.NoOp]
 
   def compile(%Document{} = document) do
     compiler = Enum.find(@compilers, & &1.recognizes?(document))
-    compiler.compile(document)
+    compile_fun = fn -> compiler.compile(document) end
+
+    case Isolation.invoke(compile_fun) do
+      {:ok, result} ->
+        result
+
+      {:error, {exception, stack}} ->
+        diagnostic = Build.Error.error_to_diagnostic(document, exception, stack, nil)
+        diagnostics = Build.Error.refine_diagnostics([diagnostic])
+        {:error, diagnostics}
+    end
   end
 end

apps/remote_control/lib/lexical/remote_control/build/isolation.ex

@@ -0,0 +1,25 @@
+defmodule Lexical.RemoteControl.Build.Isolation do
+  @moduledoc """
+  Runs functions in an isolated, monitored process
+  """
+
+  @spec invoke((() -> term())) :: {:ok, term()} | {:error, term()}
+  def invoke(function) when is_function(function, 0) do
+    me = self()
+
+    {pid, ref} =
+      spawn_monitor(fn ->
+        send(me, {:result, function.()})
+      end)
+
+    receive do
+      {:result, result} ->
+        # clean up the DOWN message from the above process in the mailbox.
+        Process.demonitor(ref, [:flush])
+        {:ok, result}
+
+      {:DOWN, ^ref, :process, ^pid, reason} ->
+        {:error, reason}
+    end
+  end
+end

apps/remote_control/lib/lexical/remote_control/build/project.ex

@@ -2,7 +2,9 @@ defmodule Lexical.RemoteControl.Build.Project do
   alias Lexical.Project
   alias Lexical.RemoteControl
   alias Lexical.RemoteControl.Build
+  alias Lexical.RemoteControl.Build.Isolation
   alias Lexical.RemoteControl.Plugin
+  alias Mix.Task.Compiler.Diagnostic
 
   use Build.Progress
   require Logger
@@ -17,7 +19,7 @@ defmodule Lexical.RemoteControl.Build.Project do
         Mix.Task.clear()
 
         with_progress building_label(project), fn ->
-          result = Mix.Task.run(:compile, mix_compile_opts(force?))
+          result = compile_in_isolation(force?)
           Mix.Task.run(:loadpaths)
           result
         end
@@ -44,6 +46,26 @@ defmodule Lexical.RemoteControl.Build.Project do
     end)
   end
 
+  defp compile_in_isolation(force?) do
+    compile_fun = fn -> Mix.Task.run(:compile, mix_compile_opts(force?)) end
+
+    case Isolation.invoke(compile_fun) do
+      {:ok, result} ->
+        result
+
+      {:error, {exception, [{_mod, _fun, _arity, meta} | _]}} ->
+        diagnostic = %Diagnostic{
+          file: Keyword.get(meta, :file),
+          severity: :error,
+          message: Exception.message(exception),
+          compiler_name: "Elixir",
+          position: Keyword.get(meta, :line, 1)
+        }
+
+        {:error, [diagnostic]}
+    end
+  end
+
   defp prepare_for_project_build(false = _force?) do
     :ok
   end

apps/remote_control/test/fixtures/compilation_callback_errors/.formatter.exs

@@ -0,0 +1,4 @@
+# Used by "mix format"
+[
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]

apps/remote_control/test/fixtures/compilation_callback_errors/.gitignore

@@ -0,0 +1,26 @@
+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where third-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
+/.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez
+
+# Ignore package tarball (built via "mix hex.build").
+compilation_errors-*.tar
+
+# Temporary files, for example, from tests.
+/tmp/

apps/remote_control/test/fixtures/compilation_callback_errors/lib/compile_callback_error.ex

@@ -0,0 +1,6 @@
+defmodule CompileCallbackError do
+  @after_verify __MODULE__
+  def __after_verify__(_) do
+    raise "boom"
+  end
+end

apps/remote_control/test/fixtures/compilation_callback_errors/mix.exs

@@ -0,0 +1,25 @@
+defmodule CompilationCallbackErrors.MixProject do
+  use Mix.Project
+
+  def project do
+    Code.put_compiler_option(:ignore_module_conflict, true)
+
+    [
+      app: :compilation_callback_errors,
+      version: "0.1.0",
+      elixir: "~> 1.13",
+      start_permanent: Mix.env() == :prod,
+      deps: deps()
+    ]
+  end
+
+  def application do
+    [
+      extra_applications: [:logger]
+    ]
+  end
+
+  defp deps do
+    []
+  end
+end