Add fallback for backwards compatibility (and hide state)

Author: benmandrew

src/build.ml

@@ -31,7 +31,7 @@ let notify ?channel ~web_ui ~service ~commit ~repo x =
   | None -> x
   | Some { Slack_channel.uri; mode; repositories = _ } ->
     let s =
-      let+ state = Current.state x
+      let+ state = Current.state ~hidden:true x
       and+ commit in
       match state, mode with
       | Error (`Msg _), Slack_channel.Failure

src/slack_channel.ml

@@ -40,5 +40,7 @@ let parse_json s =
   in
   try
     from_string s |> Util.to_list |> List.map read_channel
-  with ex ->
-    Fmt.failwith "Failed to parse slack URIs '%S': %a" s Fmt.exn ex
+  with _ ->
+    let uri = Current_slack.channel @@ Uri.of_string @@ String.trim s in
+    [ { uri; mode = All; repositories = All_repos } ]
+    (* Fmt.failwith "Failed to parse slack URIs '%S': %a" s Fmt.exn e *)