Broken with ppx using ppx_driver "Error: Attribute `with' was not used"

[ejgallego]

When using ppx_import with some other ppx rewriters such as ppx_sexp_conv we get:

ocamlfind ocamldep -package threads -package ppx_import -package ppx_sexp_conv -package str -package coq.intf -package sexplib -package coq.stm -package unix -package num -modules serlib/ser_declarations.ml > serlib/ser_declarations.ml.depends
File "serlib/ser_declarations.ml", line 59, characters 4-8:
Error: Attribute `with' was not used

Thanks!

[whitequark]

OK, ppx_deriving and ppx_sexp_conv coexistence is currently completely unusable. This is bad.
cc @diml

[ejgallego]

Edit: Adding -ppxopt "ppx_sexp_conv,-no-check" does not seem to fix the issue.

[ejgallego]

Ups, I was wrong, I was not able to fix the problem with -no-check.

[ejgallego]

I traced this back to ppx_deriving 4.2. Downgrading to 4.1 solves the problem.

[ejgallego]

That has been working fine for some time; thanks to all who have helped!

[ejgallego]

Well, the v0.10.0 versions of the JS stuff has broken ppx_import again:

File "sertop/sertop_sexp.ml", line 134, characters 4-8:
Error: Attribute `with' was not used

the situation continues to be a bit frustrating I'm afraid :(

[gasche]

If I understand things correctly, we (people willing to fix bugs in ppx_import) have no control/agency over what the drivers that you use decide to do, and to fix the problem you observe. So it's good to open the PR here to track progress, but you should really creating an issue with the people who released "the v0.10.0 versions of the JS stuff", because the fix may be on their side.

[ejgallego]

Thanks for you help @gasche , I am afraid that even after reading ocaml-ppx/ppx_deriving#153 , I don't understand what is going on, and how to even start looking at the problem.

All that I have is a simple _tags file with:

<...>: package(ppx_import), package(ppx_sexp_conv)

and a declaration such as:

type regular_inductive_arity =
  [%import: Declarations.regular_inductive_arity
  [@with Term.sorts := Sorts.t;]]
  [@@deriving sexp]

that was working fine, now I just did opam upgrade, and everything breaks again...

How am I supposed to provide a working package? I am just naive trying to combine two ppx?

What is the proper package to report the bug? In my system I see:

ppx_ast                       v0.10.0  OCaml AST used by Jane Street ppx rewrite
ppx_base                      v0.10.0  Base set of ppx rewriters
ppx_compare                   v0.10.0  Generation of comparison functions from t
ppx_core                      v0.10.0  Standard library for ppx rewriters
ppx_derivers                      1.0  Shared [@@deriving] plugin registry
ppx_deriving                    4.2.1  Type-driven code generation for OCaml >=4
ppx_driver                    v0.10.0  Feature-full driver for OCaml AST transfo
ppx_enumerate                 v0.10.0  Generate a list containing all values of 
ppx_hash                      v0.10.0  A ppx rewriter that generates hash functi
ppx_import                        1.4  A syntax extension for importing declarat
ppx_js_style                  v0.10.0  Code style checker for Jane Street Packag
ppx_metaquot                  v0.10.0  Write OCaml AST fragment using OCaml synt
ppx_optcomp                   v0.10.0  Optional compilation for OCaml
ppx_sexp_conv                 v0.10.0  Generation of S-expression conversion fun
ppx_tools                  5.1+4.06.0  Tools for authors of ppx rewriters and ot
ppx_tools_versioned             5.0.1  A variant of ppx_tools based on ocaml-mig
ppx_traverse_builtins         v0.10.0  Builtins for Ppx_traverse
ppx_type_conv                 v0.10.0  Support Library for type-driven code gene

I am having trouble to track which package is the one to blame here.
Thanks for you time and sorry for bugging you again.

[ghost]

It seems that a change in ppx_driver.v0.9 wasn't properly integrated in the development version. Hopefully this should be fixed by ocaml/opam-repository#11078

[gasche]

@diml thanks! I was about to ping you.

[ejgallego]

Thanks @diml !

[ejgallego]

v0.10.1 seems to solve the problem, uff, what a relief! XD. Thanks to both again!