fix: fallback to heuristics if workspace_folders is not set

Author: doorgan

apps/expert/lib/expert/state.ex

@@ -63,10 +63,17 @@ defmodule Expert.State do
     response = initialize_result()
 
     projects =
-      for %{uri: uri} <- event.workspace_folders do
-        Project.new(uri)
+      case event.workspace_folders do
+        nil ->
+          find_projects(event.root_uri)
+
+        _ ->
+          for %{uri: uri} <- event.workspace_folders,
+              project = Project.new(uri),
+              project.mix_project? do
+            project
+          end
       end
-      |> Enum.filter(& &1.mix_project?)
 
     ActiveProjects.set_projects(projects)
 
@@ -89,6 +96,34 @@ defmodule Expert.State do
     Configuration.default(config)
   end
 
+  defp find_projects(root_uri) do
+    root_path = Forge.Document.Path.from_uri(root_uri)
+    root_mix_exs = Path.join(root_path, "mix.exs")
+
+    projects =
+      if File.exists?(root_mix_exs) do
+        [Project.new(root_uri)]
+      else
+        find_multiroot_projects(root_path)
+      end
+
+    if projects == [], do: [Project.new(root_uri)], else: projects
+  end
+
+  defp find_multiroot_projects(root_path) do
+    mix_exs_blob = Path.join([root_path, "**", "mix.exs"])
+
+    for mix_exs_path <- Path.wildcard(mix_exs_blob),
+        "deps" not in Path.split(mix_exs_path) do
+      project_uri =
+        mix_exs_path
+        |> Path.dirname()
+        |> Forge.Document.Path.to_uri()
+
+      Project.new(project_uri)
+    end
+  end
+
   def apply(%__MODULE__{initialized?: false}, request) do
     Logger.error("Received #{request.method} before server was initialized")
     {:error, :not_initialized}

apps/expert/test/expert/expert_test.exs

@@ -64,7 +64,14 @@ defmodule ExpertTest do
 
   def initialize_request(root_path, opts \\ []) do
     id = opts[:id] || 1
-    projects = opts[:projects] || []
+    projects = Keyword.get(opts, :projects, [])
+
+    workspace_folders =
+      if not is_nil(projects) do
+        Enum.map(projects, fn project ->
+          %{uri: project.root_uri, name: Project.name(project)}
+        end)
+      end
 
     %{
       method: "initialize",
@@ -78,10 +85,7 @@ defmodule ExpertTest do
             workspaceFolders: true
           }
         },
-        workspaceFolders:
-          Enum.map(projects, fn project ->
-            %{uri: project.root_uri, name: Project.name(project)}
-          end)
+        workspaceFolders: workspace_folders
       }
     }
   end
@@ -232,6 +236,31 @@ defmodule ExpertTest do
       assert [] = Expert.ActiveProjects.projects()
       assert_project_stopped?(main_project)
     end
+
+    test "supports missing workspace_folders in the request", %{
+      client: client,
+      project_root: project_root,
+      main_project: main_project,
+      secondary_project: secondary_project
+    } do
+      assert :ok =
+               request(
+                 client,
+                 initialize_request(project_root, id: 1, projects: nil)
+               )
+
+      assert_result(1, %{
+        "capabilities" => %{"workspace" => %{"workspaceFolders" => %{"supported" => true}}}
+      })
+
+      assert [_, _] = projects = Expert.ActiveProjects.projects()
+
+      for project <- projects do
+        assert project.root_uri in [main_project.root_uri, secondary_project.root_uri]
+
+        assert_project_alive?(project)
+      end
+    end
   end
 
   describe "opening files" do