Handle non-existing input files

[sarranz]

[vbgl]

This also prints the “usage” help message; is this expected?

[sarranz]

I think it could be a good idea, as the error might come from the user not actually pointing to a file that's not there but using an option incorrectly.

[vbgl]

Also, do not forget to rebase on top of a recent version of main.

[bgregoir]

I don't understand why the CI is not happy!

[vbgl]

I guess it’s an instance of #190.

[bgregoir]

But why it is a problem for this branch and not for main ?

[vbgl]

This branch defines one new exception.

[vbgl]

The following patches hides the problem again:

--- a/compiler/src/main_compiler.ml
+++ b/compiler/src/main_compiler.ml
@@ -4,14 +4,13 @@ open Glob_options

 (* -------------------------------------------------------------------- *)
 exception UsageError
-exception InputError of input_error

 let parse () =
   let error () = raise UsageError in
   let set_in s =
     if !infile <> "" then error();
-    if not (BatSys.file_exists s) then raise (InputError (FileNotFound s));
-    if BatSys.is_directory s then raise (InputError (FileIsDirectory s));
+    if not (BatSys.file_exists s) then raise (Invalid_argument (pp_input_error (FileNotFound s)));
+    if BatSys.is_directory s then raise (Invalid_argument (pp_input_error (FileIsDirectory s)));
     infile := s  in
   (* Set default option values *)
   if Arch.os = Some `Windows then set_cc "windows";
@@ -533,8 +532,8 @@ let main () =
     Arg.usage options usage_msg;
     exit 1

-  | InputError ie ->
-    Format.eprintf "Error: %s\n" (pp_input_error ie);
+  | Invalid_argument ie ->
+    Format.eprintf "Error: %s\n" ie;
     exit 1

 (* -------------------------------------------------------------------- *)

[vbgl]

This issue should vanish once #227 is merged.