From 1de18f0e0438656f8328123f2bb009f24c47d8ee Mon Sep 17 00:00:00 2001
From: Louis Gesbert <louis.gesbert@ocamlpro.com>
Date: Mon, 15 Apr 2024 23:00:56 +0200
Subject: [PATCH] Preserve the capitalisation of module filenames

Module names must be capitalised (start with a capital letter), and the name of
the file on disk must match ; however, matching up to capitalisation is allowed,
i.e. the file on disk can start with a lowercase letter.

A mismatch between Clerk assuming generated module artifacts would match the
capitalised module name, and `catala depends` matching the names of files on
disk (because it would otherwise mean treating dependencies differently
depending on if they originate from modules or not) was causing "file not found"
errors later on in the compilation chain.

This patch enforces that the capitalisation of the original file name on
disk (which is always known) takes precedence in Clerk, matching the behaviour
of `catala depends` and fixing the issue. It's also actually a small
simplification in Clerk code.
---
 build_system/clerk_driver.ml       | 40 +++++++++++-------------------
 compiler/shared_ast/interpreter.ml |  5 +---
 2 files changed, 15 insertions(+), 30 deletions(-)

diff --git a/build_system/clerk_driver.ml b/build_system/clerk_driver.ml
index 52024aef..c5998f80 100644
--- a/build_system/clerk_driver.ml
+++ b/build_system/clerk_driver.ml
@@ -607,16 +607,16 @@ let[@ocamlformat "disable"] static_base_rules =
 
 let gen_build_statements
     (include_dirs : string list)
-    (same_dir_modules : string list)
+    (same_dir_modules : (string * File.t) list)
     (item : Scan.item) : Nj.ninja =
   let open File in
   let ( ! ) = Var.( ! ) in
   let src = item.file_name in
   let modules = List.rev item.used_modules in
   let modfile ext modname =
-    if List.mem modname same_dir_modules then
-      (!Var.builddir / src /../ modname) ^ ext
-    else modname ^ ext
+    match List.assoc_opt modname same_dir_modules with
+    | Some f -> (!Var.builddir / Filename.remove_extension f) ^ ext
+    | None -> modname ^ ext
   in
   let inc x = !Var.builddir / x in
   let modd x = modfile "@module" x in
@@ -627,24 +627,15 @@ let gen_build_statements
       ~implicit_in:(List.map inc item.included_files @ List.map modd modules)
       ~outputs:[inc srcv]
   in
+  let target_file ext = (!Var.builddir / !Var.src) ^ "." ^ ext in
   let module_deps =
     Option.map
       (fun m ->
         Nj.build "phony"
-          ~inputs:
-            [
-              inc srcv;
-              (!Var.builddir / src /../ m) ^ ".cmi";
-              (!Var.builddir / src /../ m) ^ ".cmxs";
-            ]
+          ~inputs:[inc srcv; target_file "cmi"; target_file "cmxs"]
           ~outputs:[modd m])
       item.module_def
   in
-  let target_file ext =
-    match item.module_def with
-    | Some m -> (!Var.builddir / src /../ m) ^ "." ^ ext
-    | None -> (!Var.builddir / !Var.src) ^ "." ^ ext
-  in
   let ml_file = target_file "ml" in
   let py_file = target_file "py" in
   let ocaml, python =
@@ -667,15 +658,9 @@ let gen_build_statements
   in
   let ocamlopt =
     let obj =
-      let m =
-        match item.module_def with
-        | Some m -> m
-        | None -> Filename.(basename (remove_extension src))
-      in
-      let target ext = (!Var.builddir / src /../ m) ^ "." ^ ext in
       Nj.build "ocaml-object" ~inputs:[ml_file]
         ~implicit_in:(!Var.catala_exe :: List.map modd modules)
-        ~outputs:(List.map target ["mli"; "cmi"; "cmo"; "cmx"; "cmt"; "o"])
+        ~outputs:(List.map target_file ["mli"; "cmi"; "cmo"; "cmx"; "cmt"; "o"])
         ~vars:
           [
             ( Var.ocaml_flags,
@@ -715,9 +700,9 @@ let gen_build_statements
     !Var.catala_exe
     :: List.map
          (fun m ->
-           if List.mem m same_dir_modules then
-             (!Var.builddir / src /../ m) ^ ".cmxs"
-           else m ^ "@module")
+           match List.assoc_opt m same_dir_modules with
+           | Some f -> (!Var.builddir / Filename.remove_extension f) ^ ".cmxs"
+           | None -> m ^ "@module")
          modules
   in
   let interpret =
@@ -819,7 +804,10 @@ let gen_build_statements_dir
     (include_dirs : string list)
     (items : Scan.item list) : Nj.ninja =
   let same_dir_modules =
-    List.filter_map (fun item -> item.Scan.module_def) items
+    List.filter_map
+      (fun item ->
+        Option.map (fun name -> name, item.Scan.file_name) item.Scan.module_def)
+      items
   in
   Seq.flat_map
     (gen_build_statements include_dirs same_dir_modules)
diff --git a/compiler/shared_ast/interpreter.ml b/compiler/shared_ast/interpreter.ml
index ae011b4f..7cd255a8 100644
--- a/compiler/shared_ast/interpreter.ml
+++ b/compiler/shared_ast/interpreter.ml
@@ -1090,10 +1090,7 @@ let load_runtime_modules prg =
   let load m =
     let obj_file =
       Dynlink.adapt_filename
-        File.(
-          Pos.get_file (Mark.get (ModuleName.get_info m))
-          /../ ModuleName.to_string m
-          ^ ".cmo")
+        File.(Pos.get_file (Mark.get (ModuleName.get_info m)) -.- "cmo")
     in
     if not (Sys.file_exists obj_file) then
       Message.error