unikernel/duniverse/ppxlib/test/driver/ocaml-ppx-context-load-path-migration/driver.ml

@@ -0,0 +1,92 @@
+module To_before_502 =
+  Ppxlib_ast.Convert (Ppxlib_ast.Js) (Ppxlib_ast__.Versions.OCaml_501)
+
+module From_before_502 =
+  Ppxlib_ast.Convert (Ppxlib_ast__.Versions.OCaml_501) (Ppxlib_ast.Js)
+
+module Before_502_to_ocaml =
+  Ppxlib_ast.Convert
+    (Ppxlib_ast__.Versions.OCaml_501)
+    (Ppxlib_ast.Compiler_version)
+
+module OCaml_501 = Ppxlib_ast__.Versions.OCaml_501.Ast
+
+let rec unfold_list_lit x next =
+  let open OCaml_501.Parsetree in
+  let open Astlib.Longident in
+  match next.pexp_desc with
+  | Pexp_construct ({ txt = Lident "[]"; _ }, None) -> [ x ]
+  | Pexp_construct
+      ( { txt = Lident "::"; _ },
+        Some { pexp_desc = Pexp_tuple [ elm; rest ]; _ } ) ->
+      x :: unfold_list_lit elm rest
+  | _ -> invalid_arg "list_lit"
+
+(* Only deals with the basic blocks needed for ocaml.ppx.context *)
+let rec basic_expr_to_string expr =
+  let open OCaml_501.Parsetree in
+  let open Astlib.Longident in
+  match expr.pexp_desc with
+  | Pexp_constant (Pconst_string (s, _, None)) -> Printf.sprintf "%S" s
+  | Pexp_ident { txt = Lident name; _ } -> name
+  | Pexp_tuple l ->
+      let strs = List.map basic_expr_to_string l in
+      "(" ^ String.concat ", " strs ^ ")"
+  | Pexp_construct ({ txt = Lident s; _ }, None) -> s
+  | Pexp_construct
+      ( { txt = Lident "::"; _ },
+        Some { pexp_desc = Pexp_tuple [ elm; rest ]; _ } ) ->
+      let exprs = unfold_list_lit elm rest in
+      let strs = List.map basic_expr_to_string exprs in
+      "[" ^ String.concat "; " strs ^ "]"
+  | _ -> invalid_arg "basic_expr_to_string"
+
+let print_field (lident_loc, expr) =
+  match lident_loc with
+  | { OCaml_501.Asttypes.txt = Astlib.Longident.Lident name; _ } ->
+      Printf.printf "    %s: %s;\n" name (basic_expr_to_string expr)
+  | _ -> ()
+
+let print_ocaml_ppx_context stri =
+  let open OCaml_501.Parsetree in
+  match stri.pstr_desc with
+  | Pstr_attribute
+      {
+        attr_payload =
+          PStr
+            [
+              {
+                pstr_desc =
+                  Pstr_eval ({ pexp_desc = Pexp_record (fields, None); _ }, _);
+                _;
+              };
+            ];
+        _;
+      } ->
+      Printf.printf "[@@@ocaml.ppx.context\n";
+      Printf.printf "  {\n";
+      List.iter print_field fields;
+      Printf.printf "  }\n";
+      Printf.printf "]\n"
+  | _ -> ()
+
+let is_ppx_context stri =
+  let open OCaml_501.Parsetree in
+  match stri.pstr_desc with
+  | Pstr_attribute
+      { attr_name = { OCaml_501.Asttypes.txt = "ocaml.ppx.context"; _ }; _ } ->
+      true
+  | _ -> false
+
+let impl _ctxt str =
+  let before_502_ast = To_before_502.copy_structure str in
+  let ppx_context = List.find is_ppx_context before_502_ast in
+  Printf.printf "ocaml.ppx.context before 5.02:\n";
+  print_ocaml_ppx_context ppx_context;
+  let round_trip = Before_502_to_ocaml.copy_structure_item ppx_context in
+  Printf.printf "ocaml.ppx.context round tripped:\n";
+  Ocaml_common.Pprintast.structure_item Format.std_formatter round_trip;
+  str
+
+let () = Ppxlib.Driver.V2.register_transformation ~impl "ocaml.ppx.context-test"
+let () = Ppxlib.Driver.standalone ()

unikernel/duniverse/ppxlib/test/driver/ocaml-ppx-context-load-path-migration/dune

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+(executable
+ (name driver)
+ (enabled_if
+  (>= %{ocaml_version} "5.2"))
+ (libraries
+  ppxlib
+  ppxlib.ast
+  ppxlib.astlib
+  ocaml-compiler-libs.common
+  compiler-libs.common))
+
+(cram
+ (package ppxlib)
+ (enabled_if
+  (>= %{ocaml_version} "5.2"))
+ (deps driver.exe))

unikernel/duniverse/ppxlib/test/driver/ocaml-ppx-context-load-path-migration/run.t

@@ -0,0 +1,73 @@
+In 5.2 the format of ocaml.ppx.context load_path changed.
+To ensure compat, we defined migration for ocaml.ppx.context attributes
+
+We write such an attribute to an .ml file. The compiler will add its own
+and it should be consumed by the driver but our handwritten attribute will
+be migrated as well and should remain in the AST.
+  $ cat > test.ml << EOF
+  > let x = 1
+  > [@@@ocaml.ppx.context
+  >   {
+  >     tool_name = "ocaml";
+  >     include_dirs = ["foo"];
+  >     hidden_include_dirs = [];
+  >     load_path = (["foo"; "bar"], ["baz"]);
+  >     open_modules = [];
+  >     for_package = None;
+  >     debug = true;
+  >     use_threads = false;
+  >     use_vmthreads = false;
+  >     recursive_types = false;
+  >     principal = false;
+  >     transparent_modules = false;
+  >     unboxed_types = false;
+  >     unsafe_string = false;
+  >     cookies = []
+  >   }]
+  > EOF
+
+We then run a custom driver that will read our ast, migrate it back to 5.01,
+pretty print the ocaml.ppx.context, convert it back to the latest version and
+pretty print it again. This last, round-tripped version should be identical to
+the one above.
+
+  $ ./driver.exe --impl test.ml -o ignore.ml
+  ocaml.ppx.context before 5.02:
+  [@@@ocaml.ppx.context
+    {
+      tool_name: "ocaml";
+      include_dirs: ["foo"];
+      hidden_include_dirs: [];
+      load_path: ["foo"; "bar"; "baz"];
+      open_modules: [];
+      for_package: None;
+      debug: true;
+      use_threads: false;
+      use_vmthreads: false;
+      recursive_types: false;
+      principal: false;
+      transparent_modules: false;
+      unboxed_types: false;
+      unsafe_string: false;
+      cookies: [];
+    }
+  ]
+  ocaml.ppx.context round tripped:
+  [@@@ocaml.ppx.context
+    {
+      tool_name = "ocaml";
+      include_dirs = ["foo"];
+      hidden_include_dirs = [];
+      load_path = (["foo"; "bar"], ["baz"]);
+      open_modules = [];
+      for_package = None;
+      debug = true;
+      use_threads = false;
+      use_vmthreads = false;
+      recursive_types = false;
+      principal = false;
+      transparent_modules = false;
+      unboxed_types = false;
+      unsafe_string = false;
+      cookies = []
+    }]