fix: ensure id always exists while handling requests

lib/gen_lsp.ex

@@ -332,7 +332,7 @@ defmodule GenLSP do
         start = System.system_time(:microsecond)
         :telemetry.execute([:gen_lsp, :request, :client, :start], %{})
 
-        me = self()
+        id = request["id"]
 
         {:ok, task} =
           attempt(
@@ -352,7 +352,7 @@ defmodule GenLSP do
 
                 packet = %{
                   "jsonrpc" => "2.0",
-                  "id" => Process.get(:request_id),
+                  "id" => id,
                   "error" => output
                 }
 
@@ -363,10 +363,7 @@ defmodule GenLSP do
 
               _ ->
                 case GenLSP.Requests.new(request) do
-                  {:ok, %{id: id} = req} ->
-                    Process.put(:request_id, id)
-                    send(me, {:request_id, id})
-
+                  {:ok, req} ->
                     result =
                       :telemetry.span([:gen_lsp, :handle_request], %{method: req.method}, fn ->
                         {lsp.mod.handle_request(req, lsp), %{}}
@@ -455,7 +452,7 @@ defmodule GenLSP do
 
                     packet = %{
                       "jsonrpc" => "2.0",
-                      "id" => request["id"],
+                      "id" => id,
                       "error" => output
                     }
 
@@ -464,12 +461,6 @@ defmodule GenLSP do
             end
           )
 
-        id =
-          receive do
-            {:request_id, id} ->
-              id
-          end
-
         tasks = Map.put(lsp.tasks, id, task)
 
         lsp = put_in(lsp.tasks, tasks)

test/gen_lsp_test.exs

@@ -324,7 +324,7 @@ defmodule GenLSPTest do
     assert log =~ expected_msg
   end
 
-  test "returns an invalid request when the paylaod is not parseable, but is still deemed a request",
+  test "returns an invalid request when the payload is not parseable, but is still deemed a request",
        %{client: client} do
     assert :ok == request(client, %{"id" => "bingo", "random" => "stuff"})
 
@@ -336,6 +336,38 @@ defmodule GenLSPTest do
                  500
   end
 
+  test "gracefully recovers from invalid requests and continues to accept requests",
+       %{client: client} do
+    assert :ok == request(client, %{"id" => "whoops", "random" => "again"})
+
+    assert_error "whoops",
+                 %{
+                   "message" => "Invalid request from the client" <> _,
+                   "code" => -32600
+                 },
+                 500
+
+    id = System.unique_integer([:positive])
+
+    assert :ok ==
+             request(client, %{
+               "jsonrpc" => "2.0",
+               "method" => "initialize",
+               "params" => %{"capabilities" => %{}},
+               "id" => id
+             })
+
+    assert_result ^id,
+                  %{
+                    "capabilities" => %{
+                      "callHierarchyProvider" => %{"workDoneProgress" => true},
+                      "experimental" => nil
+                    },
+                    "serverInfo" => %{"name" => "Test LSP"}
+                  },
+                  500
+  end
+
   test "logs when an invalid payload is received", %{client: client} do
     assert capture_log(fn ->
              assert :ok == notify(client, %{"random" => "stuff"})