fix: update document store on didchange even without the engine running (#326)

We were dropping this event if the engine for that project wasn't
running because it would attempt to trigger a document compilation.

Skipping the document compilation is correct, but we should still be
updating the document store with the new document contents.

Author: doorgan

apps/expert/lib/expert/state.ex

@@ -128,30 +128,23 @@ defmodule Expert.State do
     projects = ActiveProjects.projects()
     project = Project.project_for_uri(projects, uri)
 
-    with true <- ActiveProjects.active?(project),
-         {:ok, updated_source} <-
-           Document.Store.get_and_update(
-             uri,
-             # TODO: this function needs to accept the GenLSP data structure
-             &Document.apply_content_changes(&1, version, params.content_changes)
-           ) do
-      updated_message =
-        file_changed(
-          uri: updated_source.uri,
-          open?: true,
-          from_version: version,
-          to_version: updated_source.version
-        )
-
-      EngineApi.broadcast(project, updated_message)
-      EngineApi.compile_document(project, updated_source)
-      {:ok, state}
-    else
-      false ->
-        GenLSP.info(
-          Expert.get_lsp(),
-          "Received request textDocument/didChange before engine for #{Project.name(project)} was initialized. Ignoring."
-        )
+    case Document.Store.get_and_update(
+           uri,
+           &Document.apply_content_changes(&1, version, params.content_changes)
+         ) do
+      {:ok, updated_source} ->
+        updated_message =
+          file_changed(
+            uri: updated_source.uri,
+            open?: true,
+            from_version: version,
+            to_version: updated_source.version
+          )
+
+        if ActiveProjects.active?(project) do
+          EngineApi.broadcast(project, updated_message)
+          EngineApi.compile_document(project, updated_source)
+        end
 
         {:ok, state}
 

apps/expert/test/expert/expert_test.exs

@@ -561,4 +561,63 @@ defmodule ExpertTest do
       assert_project_alive?(nested_subproject)
     end
   end
+
+  describe "text document changes" do
+    test "updates document store even when project engine is not active", %{
+      client: client,
+      project_root: project_root
+    } do
+      spy(Expert.EngineApi)
+
+      patch(Expert.Project.Supervisor, :ensure_node_started, fn _project ->
+        {:ok, nil}
+      end)
+
+      assert :ok = request(client, initialize_request(project_root, id: 1, projects: []))
+      assert_result(1, _)
+
+      file_uri = Document.Path.to_uri(Path.join(project_root, "lib/test_file.ex"))
+      initial_text = "defmodule Test do\nend"
+
+      assert :ok =
+               notify(client, %{
+                 method: "textDocument/didOpen",
+                 jsonrpc: "2.0",
+                 params: %{
+                   textDocument: %{
+                     uri: file_uri,
+                     languageId: "elixir",
+                     version: 1,
+                     text: initial_text
+                   }
+                 }
+               })
+
+      Process.sleep(50)
+
+      assert {:ok, doc} = Document.Store.fetch(file_uri)
+      assert Document.to_string(doc) == initial_text
+
+      new_text = "defmodule Updated do\nend"
+
+      assert :ok =
+               notify(client, %{
+                 method: "textDocument/didChange",
+                 jsonrpc: "2.0",
+                 params: %{
+                   textDocument: %{uri: file_uri, version: 2},
+                   contentChanges: [%{text: new_text}]
+                 }
+               })
+
+      Process.sleep(50)
+
+      assert {:ok, updated_doc} = Document.Store.fetch(file_uri)
+      assert updated_doc.version == 2
+      assert Document.to_string(updated_doc) == new_text
+
+      refute_any_call(Expert.EngineApi.broadcast())
+      refute_any_call(Expert.EngineApi.compile_document())
+    end
+  end
 end