feat(extension): credo (#163)

Proves Credo diagnostics for projects that include Credo.

Closes #16 

TODO: Code actions

Author: mhanberg

Diff for: lib/next_ls.ex

@@ -63,7 +63,8 @@ defmodule NextLS do
     dynamic_supervisor = Keyword.fetch!(args, :dynamic_supervisor)
 
     registry = Keyword.fetch!(args, :registry)
-    extensions = Keyword.get(args, :extensions, [NextLS.ElixirExtension])
+
+    extensions = Keyword.get(args, :extensions, [NextLS.ElixirExtension, NextLS.CredoExtension])
     cache = Keyword.fetch!(args, :cache)
     {:ok, logger} = DynamicSupervisor.start_child(dynamic_supervisor, {NextLS.Logger, lsp: lsp})
 
@@ -363,7 +364,11 @@ defmodule NextLS do
       {:ok, _} =
         DynamicSupervisor.start_child(
           lsp.assigns.dynamic_supervisor,
-          {extension, cache: lsp.assigns.cache, registry: lsp.assigns.registry, publisher: self()}
+          {extension,
+           cache: lsp.assigns.cache,
+           registry: lsp.assigns.registry,
+           publisher: self(),
+           task_supervisor: lsp.assigns.runtime_task_supervisor}
         )
     end
 
@@ -411,7 +416,14 @@ defmodule NextLS do
                if status == :ready do
                  Progress.stop(lsp, token, "NextLS runtime for folder #{name} has initialized!")
                  GenLSP.log(lsp, "[NextLS] Runtime for folder #{name} is ready...")
-                 send(parent, {:runtime_ready, name, self()})
+
+                 msg = {:runtime_ready, name, self()}
+
+                 dispatch(lsp.assigns.registry, :extensions, fn entries ->
+                   for {pid, _} <- entries, do: send(pid, msg)
+                 end)
+
+                 send(parent, msg)
                else
                  Progress.stop(lsp, token)
                  GenLSP.error(lsp, "[NextLS] Runtime for folder #{name} failed to initialize")
@@ -526,7 +538,13 @@ defmodule NextLS do
                  if status == :ready do
                    Progress.stop(lsp, token, "NextLS runtime for folder #{name} has initialized!")
                    GenLSP.log(lsp, "[NextLS] Runtime for folder #{name} is ready...")
-                   send(parent, {:runtime_ready, name, self()})
+                   msg = {:runtime_ready, name, self()}
+
+                   dispatch(lsp.assigns.registry, :extensions, fn entries ->
+                     for {pid, _} <- entries, do: send(pid, msg)
+                   end)
+
+                   send(parent, msg)
                  else
                    Progress.stop(lsp, token)
                    GenLSP.error(lsp, "[NextLS] Runtime for folder #{name} failed to initialize")
@@ -596,8 +614,6 @@ defmodule NextLS do
   end
 
   def handle_info(:publish, lsp) do
-    GenLSP.log(lsp, "[NextLS] Compiled!")
-
     all =
       for {_namespace, cache} <- DiagnosticCache.get(lsp.assigns.cache), {file, diagnostics} <- cache, reduce: %{} do
         d -> Map.update(d, file, diagnostics, fn value -> value ++ diagnostics end)

Diff for: lib/next_ls/db.ex

@@ -162,6 +162,12 @@ defmodule NextLS.DB do
       is_atom(arg) and String.starts_with?(to_string(arg), "Elixir.") ->
         Macro.to_string(arg)
 
+      arg in [nil, :undefined] ->
+        arg
+
+      is_atom(arg) ->
+        to_string(arg)
+
       true ->
         arg
     end

Diff for: lib/next_ls/extensions/credo_extension.ex

@@ -0,0 +1,160 @@
+defmodule NextLS.CredoExtension do
+  @moduledoc false
+  use GenServer
+
+  alias GenLSP.Enumerations.DiagnosticSeverity
+  alias GenLSP.Structures.CodeDescription
+  alias GenLSP.Structures.Diagnostic
+  alias GenLSP.Structures.Position
+  alias GenLSP.Structures.Range
+  alias NextLS.DiagnosticCache
+  alias NextLS.Runtime
+
+  def start_link(args) do
+    GenServer.start_link(
+      __MODULE__,
+      Keyword.take(args, [:cache, :registry, :publisher, :task_supervisor]),
+      Keyword.take(args, [:name])
+    )
+  end
+
+  @impl GenServer
+  def init(args) do
+    cache = Keyword.fetch!(args, :cache)
+    registry = Keyword.fetch!(args, :registry)
+    publisher = Keyword.fetch!(args, :publisher)
+    task_supervisor = Keyword.fetch!(args, :task_supervisor)
+
+    Registry.register(registry, :extensions, :credo)
+
+    {:ok,
+     %{
+       runtimes: Map.new(),
+       cache: cache,
+       registry: registry,
+       task_supervisor: task_supervisor,
+       publisher: publisher,
+       refresh_refs: Map.new()
+     }}
+  end
+
+  @impl GenServer
+
+  def handle_info({:runtime_ready, _, _}, state), do: {:noreply, state}
+
+  def handle_info({:compiler, _diagnostics}, state) do
+    {state, refresh_refs} =
+      dispatch(state.registry, :runtimes, fn entries ->
+        # loop over runtimes
+        for {runtime, %{path: path}} <- entries, reduce: {state, %{}} do
+          {state, refs} ->
+            # determine the existence of Credo and memoize the result
+            state =
+              if not Map.has_key?(state.runtimes, runtime) do
+                case Runtime.call(runtime, {Code, :ensure_loaded?, [Credo]}) do
+                  {:ok, true} ->
+                    :next_ls
+                    |> :code.priv_dir()
+                    |> Path.join("monkey/_next_ls_private_credo.ex")
+                    |> then(&Runtime.call(runtime, {Code, :compile_file, [&1]}))
+
+                    Runtime.call(runtime, {Application, :ensure_all_started, [:credo]})
+                    Runtime.call(runtime, {GenServer, :call, [Credo.CLI.Output.Shell, {:suppress_output, true}]})
+
+                    put_in(state.runtimes[runtime], true)
+
+                  _ ->
+                    state
+                end
+              else
+                state
+              end
+
+            # if runtime has Credo
+            if state.runtimes[runtime] do
+              namespace = {:credo, path}
+              DiagnosticCache.clear(state.cache, namespace)
+
+              task =
+                Task.Supervisor.async_nolink(state.task_supervisor, fn ->
+                  case Runtime.call(runtime, {:_next_ls_private_credo, :issues, [path]}) do
+                    {:ok, issues} -> issues
+                    _error -> []
+                  end
+                end)
+
+              {state, Map.put(refs, task.ref, namespace)}
+            else
+              {state, refs}
+            end
+        end
+      end)
+
+    send(state.publisher, :publish)
+
+    {:noreply, put_in(state.refresh_refs, refresh_refs)}
+  end
+
+  def handle_info({ref, issues}, %{refresh_refs: refs} = state) when is_map_key(refs, ref) do
+    Process.demonitor(ref, [:flush])
+    {{:credo, path} = namespace, refs} = Map.pop(refs, ref)
+
+    for issue <- issues do
+      diagnostic = %Diagnostic{
+        range: %Range{
+          start: %Position{
+            line: issue.line_no - 1,
+            character: (issue.column || 1) - 1
+          },
+          end: %Position{
+            line: issue.line_no - 1,
+            character: 999
+          }
+        },
+        severity: category_to_severity(issue.category),
+        data: %{check: issue.check, file: issue.filename},
+        source: "credo",
+        code: Macro.to_string(issue.check),
+        code_description: %CodeDescription{
+          href: "https://hexdocs.pm/credo/#{Macro.to_string(issue.check)}.html"
+        },
+        message: issue.message
+      }
+
+      DiagnosticCache.put(state.cache, namespace, Path.join(path, issue.filename), diagnostic)
+    end
+
+    send(state.publisher, :publish)
+
+    {:noreply, put_in(state.refresh_refs, refs)}
+  end
+
+  def handle_info({:DOWN, ref, :process, _pid, _reason}, %{refresh_refs: refs} = state) when is_map_key(refs, ref) do
+    {_, refs} = Map.pop(refs, ref)
+
+    {:noreply, put_in(state.refresh_refs, refs)}
+  end
+
+  defp dispatch(registry, key, callback) do
+    ref = make_ref()
+    me = self()
+
+    Registry.dispatch(registry, key, fn entries ->
+      result = callback.(entries)
+
+      send(me, {ref, result})
+    end)
+
+    receive do
+      {^ref, result} -> result
+    end
+  end
+
+  defp category_to_severity(:refactor), do: DiagnosticSeverity.error()
+  defp category_to_severity(:warning), do: DiagnosticSeverity.warning()
+  defp category_to_severity(:design), do: DiagnosticSeverity.information()
+
+  defp category_to_severity(:consistency), do: DiagnosticSeverity.information()
+
+  defp category_to_severity(:readability), do: DiagnosticSeverity.information()
+end

Diff for: lib/next_ls/extensions/elixir_extension.ex

@@ -24,6 +24,10 @@ defmodule NextLS.ElixirExtension do
   end
 
   @impl GenServer
+  def handle_info({:runtime_ready, _path, _pid}, state) do
+    {:noreply, state}
+  end
+
   def handle_info({:compiler, diagnostics}, state) when is_list(diagnostics) do
     DiagnosticCache.clear(state.cache, :elixir)
 

Diff for: lib/next_ls/runtime.ex

@@ -50,7 +50,7 @@ defmodule NextLS.Runtime do
     on_initialized = Keyword.fetch!(opts, :on_initialized)
     db = Keyword.fetch!(opts, :db)
 
-    Registry.register(registry, :runtimes, %{name: name, uri: uri, db: db})
+    Registry.register(registry, :runtimes, %{name: name, uri: uri, path: working_dir, db: db})
 
     pid =
       cond do
@@ -214,6 +214,8 @@ defmodule NextLS.Runtime do
               for {pid, _} <- entries, do: send(pid, {:compiler, diagnostics})
             end)
 
+            NextLS.Logger.log(state.logger, "Compiled #{state.name}!")
+
             diagnostics
 
           unknown ->

Diff for: priv/monkey/_next_ls_private_credo.ex

@@ -0,0 +1,9 @@
+defmodule :_next_ls_private_credo do
+  @moduledoc false
+
+  def issues(dir) do
+    ["--strict", "--all", "--working-dir", dir]
+    |> Credo.run()
+    |> Credo.Execution.get_issues()
+  end
+end

Diff for: test/next_ls/dependency_test.exs

@@ -59,10 +59,6 @@ defmodule NextLS.DependencyTest do
       def bar() do
         42
       end
-
-      def call_baz() do
-        Baz.baz()
-      end
     end
     """)
 
@@ -264,7 +260,6 @@ defmodule NextLS.DependencyTest do
           elixir: "~> 1.10",
           deps: [
             {:bar, path: "../bar"},
-            {:baz, path: "../baz"}
           ]
         ]
       end