Make plugin load failures less verbose

In general you don't care unless you may have attempted to use one.

compiler/driver.ml

@@ -1102,7 +1102,9 @@ let main () =
   let open Cmdliner in
   match Cmd.eval_value ~catch:false ~argv command with
   | Ok _ -> exit Cmd.Exit.ok
-  | Error _ -> exit Cmd.Exit.cli_error
+  | Error e ->
+    if e = `Term then Plugin.print_failures ();
+    exit Cmd.Exit.cli_error
   | exception Cli.Exit_with n -> exit n
   | exception Message.CompilerError content ->
     let bt = Printexc.get_raw_backtrace () in

compiler/plugin.ml

@@ -29,6 +29,13 @@ let register info term =
 let list () = Hashtbl.to_seq_values backend_plugins |> List.of_seq
 let names () = Hashtbl.to_seq_keys backend_plugins |> List.of_seq
 
+let load_failures = Hashtbl.create 17
+
+let print_failures () =
+  if Hashtbl.length load_failures > 0 then
+    Message.emit_warning "Some plugins could not be loaded:@,%a"
+      (Format.pp_print_seq (fun ppf -> Format.fprintf ppf "  - %s")) (Hashtbl.to_seq_values load_failures)
+
 let load_file f =
   try
     Dynlink.loadfile f;
@@ -36,6 +43,10 @@ let load_file f =
   with
   | Dynlink.Error (Dynlink.Module_already_loaded s) ->
     Message.emit_debug "Plugin %S (%s) was already loaded, skipping" f s
+  | Dynlink.Error err ->
+    let msg = Dynlink.error_message err in
+    Message.emit_debug "Could not load plugin %S: %s" f msg;
+    Hashtbl.add load_failures f msg
   | e ->
     Message.emit_warning "Could not load plugin %S: %s" f (Printexc.to_string e)
 

compiler/plugin.mli

@@ -41,3 +41,6 @@ val load_file : string -> unit
 
 val load_dir : string -> unit
 (** Load all plugins found in the given directory *)
+
+val print_failures : unit -> unit
+(** Dynlink errors may be silenced at startup time if not in --debug mode, this prints them as warnings *)

compiler/scalc/from_lcalc.ml

@@ -543,6 +543,7 @@ and translate_statements (ctxt : 'm ctxt) (block_expr : 'm L.expr) : A.block =
           Expr.pos block_expr );
       ]
   | _ -> (
+    Message.emit_debug "E: %a" Expr.format block_expr;
     let e_stmts, new_e = translate_expr ctxt block_expr in
     e_stmts
     @