Compile in-process on OCaml domains in OCaml rewatch

CONTRIBUTING.md

@@ -284,14 +284,14 @@ npm link rescript
 
 #### Use Local BSC with Existing ReScript Installation
 
-Alternatively, you can set the `RESCRIPT_BSC_EXE` environment variable to point to your locally compiled `bsc.exe`.
+The `rescript` build system has the compiler built in, so to test a local compiler change, link the local package as shown above.
+
+The Rust build system, `rescript-rust`, still runs `bsc.exe` and accepts the `RESCRIPT_BSC_EXE` environment variable pointing to your locally compiled `bsc.exe`:
 
 ```sh
-RESCRIPT_BSC_EXE=your-rescript-repo/packages/@rescript/darwin-arm64/bin/bsc.exe npx rescript
+RESCRIPT_BSC_EXE=your-rescript-repo/packages/@rescript/darwin-arm64/bin/bsc.exe npx rescript-rust
 ```
 
-This will test the local compiler while still using the build system from the installed Node module.
-
 ### Running Automatic Tests
 
 We provide different test suites for different levels of the compiler and build system infrastructure. Always make sure to locally build your compiler before running any tests.

analysis/src/completion_back_end.ml

@@ -967,16 +967,28 @@ and get_completions_for_context_path ~state ~debug ~full ~opens ~raw_opens ~pos
   match context_path with
   | CPString ->
     if Debug.verbose () then print_endline "[ctx_path]--> CPString";
-    [Completion.create "dummy" ~env ~kind:(Completion.Value Predef.type_string)]
+    [
+      Completion.create "dummy" ~env
+        ~kind:(Completion.Value (Predef.type_string ()));
+    ]
   | CPBool ->
     if Debug.verbose () then print_endline "[ctx_path]--> CPBool";
-    [Completion.create "dummy" ~env ~kind:(Completion.Value Predef.type_bool)]
+    [
+      Completion.create "dummy" ~env
+        ~kind:(Completion.Value (Predef.type_bool ()));
+    ]
   | CPInt ->
     if Debug.verbose () then print_endline "[ctx_path]--> CPInt";
-    [Completion.create "dummy" ~env ~kind:(Completion.Value Predef.type_int)]
+    [
+      Completion.create "dummy" ~env
+        ~kind:(Completion.Value (Predef.type_int ()));
+    ]
   | CPFloat ->
     if Debug.verbose () then print_endline "[ctx_path]--> CPFloat";
-    [Completion.create "dummy" ~env ~kind:(Completion.Value Predef.type_float)]
+    [
+      Completion.create "dummy" ~env
+        ~kind:(Completion.Value (Predef.type_float ()));
+    ]
   | CPArray None ->
     if Debug.verbose () then print_endline "[ctx_path]--> CPArray (no payload)";
     [
@@ -1984,7 +1996,9 @@ let rec complete_typed_value ?(type_arg_context : type_arg_context option)
     if prefix = "" then
       [
         create "\"\"" ~includes_snippets:true ~insert_text:"\"$0\""
-          ~sort_text:"A" ~kind:(Value Predef.type_string) ~env;
+          ~sort_text:"A"
+          ~kind:(Value (Predef.type_string ()))
+          ~env;
       ]
     else []
   | Tfunction {env; typ; args; return_type}

analysis/src/module_resolution.ml

@@ -3,7 +3,7 @@ let ( /+ ) = Filename.concat
 let rec resolve_node_module_path ~start_path name =
   if name = "@rescript/runtime" then
     (* Hack: we need a reliable way to resolve modules in monorepos. *)
-    Some !Runtime_package.path
+    Some (Runtime_package.get_path ())
   else
     let scope = Filename.dirname name in
     let name = Filename.basename name in

changes/in-process-compilation.polish.md

@@ -0,0 +1 @@
+- Speed up `rescript` builds by compiling modules inside the build system on several CPU cores, instead of starting `bsc` for every file. https://github.com/rescript-lang/rescript/pull/8781

changes/ppx-temp-file-cleanup.fix.md

@@ -0,0 +1 @@
+- Remove the temporary PPX files when a PPX fails or a build is interrupted. https://github.com/rescript-lang/rescript/pull/8781

compiler/bsc/build_identity_gen.ml

@@ -0,0 +1,38 @@
+let () =
+  let relevant file =
+    Filename.basename file = "dune"
+    || List.exists (Filename.check_suffix file) [".ml"; ".mli"; ".c"; ".h"]
+  in
+  let files =
+    Array.to_list Sys.argv |> List.tl |> List.filter relevant
+    |> List.sort String.compare
+  in
+  let normalize path =
+    String.map
+      (function
+        | '\\' -> '/'
+        | character -> character)
+      path
+  in
+  let has_suffix suffix =
+    List.exists
+      (fun file -> Filename.check_suffix (normalize file) suffix)
+      files
+  in
+  [
+    "/flow_parser/parser/expression_parser.ml";
+    "/ext/ext_platform_primitives_stubs.c";
+    "/ext/platform/native/ext_platform_primitives.ml";
+    "/core/platform/native/js_name_of_module_id.ml";
+    "/syntax/src/res_driver.ml";
+    "/syntax/src/dune";
+  ]
+  |> List.iter (fun suffix ->
+      if not (has_suffix suffix) then
+        failwith ("compiler identity is missing required input " ^ suffix));
+  let digest =
+    files
+    |> List.map (fun file -> file ^ "\000" ^ Digest.file file)
+    |> String.concat "\000" |> Digest.string
+  in
+  Printf.printf "let value = %S\n" (Digest.to_hex digest)

compiler/bsc/dune

@@ -3,10 +3,46 @@
   (flags
    (:standard -ccopt -static))))
 
+(executable
+ (name build_identity_gen)
+ (modules build_identity_gen))
+
+(rule
+ (target rescript_compiler_build_identity.ml)
+ (deps
+  build_identity_gen.ml
+  dune
+  rescript_compiler_driver.ml
+  rescript_compiler_driver.mli
+  rescript_compiler_main.ml
+  rescript_compiler_main.mli
+  (source_tree ../common)
+  (source_tree ../core)
+  (source_tree ../depends)
+  (source_tree ../ext)
+  (source_tree ../flow_parser)
+  (source_tree ../frontend)
+  (source_tree ../gentype)
+  (source_tree ../ml)
+  (source_tree ../syntax))
+ (action
+  (with-stdout-to
+   %{target}
+   (run ./build_identity_gen.exe %{deps}))))
+
+(library
+ (name rescript_compiler_driver)
+ (wrapped false)
+ (modules rescript_compiler_driver rescript_compiler_build_identity)
+ (instrumentation
+  (backend bisect_ppx))
+ (libraries common core depends flow_parser gentype syntax unix))
+
 (executable
  (name rescript_compiler_main)
+ (modules rescript_compiler_main)
  (public_name bsc)
  (package rescript)
  (instrumentation
   (backend bisect_ppx))
- (libraries common core depends flow_parser gentype syntax))
+ (libraries rescript_compiler_driver))