action, state: clean up when receive PR closed event

Author: dombong

lib/action.ml

@@ -271,6 +271,12 @@ module Action (Github_api : Api.Github) (Slack_api : Api.Slack) = struct
       end
     | _ -> Lwt.return_unit
 
+  let cleanup_state (ctx : Context.t) (payload : Github.t) =
+    match payload with
+    | Github.Pull_request { action = Closed; pull_request = { number; _ }; repository = { url; _ }; _ } ->
+      State.close_issue ctx.state url number
+    | _ -> Lwt.return_unit
+
   let process_github_notification (ctx : Context.t) headers body =
     let validate_signature secrets payload =
       let repo = Github.repo_of_notification payload in
@@ -300,6 +306,7 @@ module Action (Github_api : Api.Github) (Slack_api : Api.Slack) = struct
             ( match ctx.state_filepath with
             | None -> Lwt.return_unit
             | Some path ->
+              let%lwt () = cleanup_state ctx payload in
               ( match%lwt State.save ctx.state path with
               | Ok () -> Lwt.return_unit
               | Error e -> action_error e

lib/state.ml

@@ -65,7 +65,7 @@ let get_review_msg { state; _ } repo_url ~issue_num review_id =
 let close_issue { state; lock } repo_url issue_num =
   Lwt_mutex.with_lock lock @@ fun () ->
   let repo_state = find_or_add_repo' state repo_url in
-  Stringtbl.remove repo_state.issue_tbl issue_num;
+  Stringtbl.remove repo_state.issue_tbl (Int.to_string issue_num);
   Lwt.return_unit
 
 let set_bot_user_id { state; _ } user_id = state.State_t.bot_user_id <- Some user_id