CHANGES.md

Ppx_deriving becomes an optional dependency of ppx_type_conv

There are two ways of using the ppx_sexp_conv ppx rewriter:

• the legacy way, with:

  $ ocamlfind ocamlc -package ppx_sexp_conv ...
  

• the new way, with a driver. Since the v0.9.0 version of ppx_sexp_conv one can use either the ocaml-migrate-parsetree driver or ppx_driver. Before v0.9.0 one could only use ppx_driver

Using the legacy way requires using ppx_deriving. ppx_deriving used to be a hard dependency of ppx_sexp_conv through ppx_type_conv. Since v0.9.0 it is an optional one. As a result pacakges building using the legacy way must declare an explicit dependency on ppx_deriving.

Many packages didn't at the time ppx_sexp_conv v0.9.0 was released. To fix builds failure, a ppx_deriving dependency was added to all packages depending on ppx_sexp_conv but not ppx_deriving.

Split build and install steps (2016-05-18)

The opam tool has been separating the "build" and "install" steps of packages since version 1.2.2, but historically packages could only define a "build:" field in their metadata, that did both steps. There are many usages and tools that can benefit from the split (like tracking of installed files without losing build parallelism), and it is cleaner overall.

To upgrade older packages that didn't make the move yet, an heuristic has been applied to automatically do the split. It's in the admin-scripts/split-install.ml script and simply reads commands from the end, detecting calls to install, cp to appropriate destinations, and commands mentioning install.

The main invariant to respect is that the build stage should never write outside of its build directory and the temp dir, while the install stage should be as fast as possible. So in case of doubt, it is better to put everything in install: instead (but we don't do that automatically, since many correct packages only have build: and a .install file, which we can't detect from the metadata alone).

In turn, opam guarantees that install and remove commands are never run concurrently.

Please remember to correctly split the two stages from now on, as advised by opam lint; tools to check the invariants are being put in place.

Camlp4 syntax extensions split from Jane Street packages (2016-01-11)

Jane Street packages no longer support camlp4 after the 113.09.00 series.

For Jane Street packages that contain both a library and a camlp4 syntax extension, the latter is extracted to its own package.

The following table summarize the changes:

Package	Old findlib name of syntax	New camlp4-only package	version
sexplib	sexplib.syntax	pa_sexp_conv	113.00.00
bin_prot	bin_prot.syntax	pa_bin_prot	113.00.00
typerep	typerep.syntax	pa_typerep_conv	113.00.00
fieldslib	fieldslib.syntax	pa_fields_conv	113.00.00
variantslib	variantslib.syntax	pa_variants_conv	109.15.03

Upgrading

For the long term it is recommended to switch to the corresponding ppx alternative (replace the pa_ prefix by ppx_ to get the ppx package name).

Until then packages that are using one of the camlp4 syntax extension must upgrade their build system to refer to the new package name. Simply replace the name in the second column by the one in the third column.

Running the following shell command on the sources should do:

sed -ri 's/\<sexplib\.syntax\>/pa_sexp_conv/g;
         s/\<bin_prot\.syntax\>/pa_bin_prot/g;
         s/\<typerep\.syntax\>/pa_typerep_conv/g;
         s/\<fieldslib\.syntax\>/pa_fields_conv/g;
         s/\<variantslib\.syntax\>/pa_variants_conv/g' \
  `ag -l .`

The new dependency must also be added to the opam file.

Automatic upgrade of the opam-repository

To avoid the opam-repository being in a inconsistent state once the camlp4-free Jane Street packages are released, the following automatic change is applied to the opam repository:

for js_pkg in "sexplib" "bin_prot" "type_conv" "variantslib" "fieldslib":
  for pkg in all_packages():
    if pkg depends on js_pkg and "type_conv":
      pkg.add_constraint(js_pkg < next-version-of(js_pkg))

This is an over-approximation as some package might not use the syntax extension at all.

Following this automatic change maintainers should:

• just remove the constraint if the package doesn't use the syntax extension
• do a new release that depend on the new camlp4-only package