Prevent initializing stereotool with two different libraries. (#4182)

src/core/operators/stereotool_op.ml

@@ -171,10 +171,18 @@ let _ =
       let preset = Lang.to_valued_option Lang.to_string preset_val in
       let handler =
         let library = Utils.check_readable ~pos:(Lang.pos p) library in
-        try Stereotool.init ?license_key ~filename:library ()
-        with Stereotool.Library_not_found ->
-          Runtime_error.raise ~pos:(Lang.pos p)
-            ~message:"Invalid stereotool library" "invalid"
+        try Stereotool.init ?license_key ~filename:library () with
+          | Stereotool.Library_not_found ->
+              Runtime_error.raise ~pos:(Lang.pos p)
+                ~message:"Invalid stereotool library" "invalid"
+          | Stereotool.Library_initialized f ->
+              Runtime_error.raise ~pos:(Lang.pos p)
+                ~message:
+                  (Printf.sprintf
+                     "Stereotool already initialized with a different library: \
+                      %s"
+                     (Lang_string.quote_string f))
+                "invalid"
       in
       (match preset with
         | None -> ()

src/stereotool/stereotool.ml

@@ -10,6 +10,7 @@ module type Config = sig
 end
 
 exception Library_not_found
+exception Library_initialized of string
 
 let strnlen = foreign "strnlen" (ocaml_bytes @-> int @-> returning int)
 
@@ -78,7 +79,12 @@ let int_of_load_type = function
   | `Repair_no_pnr -> 11069
   | `Sublevel_pnr -> 10699
 
+let initialized = Atomic.make None
+
 let init ?license_key ~filename () =
+  (match Atomic.get initialized with
+    | Some f when f <> filename -> raise (Library_initialized f)
+    | _ -> Atomic.set initialized (Some filename));
   try
     let module C = C (struct
       let filename = filename

src/stereotool/stereotool.mli

@@ -15,6 +15,7 @@ type load_type =
   | `Sublevel_pnr ]
 
 exception Library_not_found
+exception Library_initialized of string
 
 val init : ?license_key:string -> filename:string -> unit -> t
 val software_version : t -> int