Restrict ppx_deriving_yojson dependency to yojson < 1.6

[NathanReb]

Yojson 1.6 deprecates the type json in favor of the new type t.
This shouldn't be an issue but users of ppx_deriving_yojson and
dune are gonna have a hard time working with yojson 1.6 since warning 3
is fatal in the default dune profile and they can't change
ppx_deriving_yojson output.

[NathanReb]

Looks like the usual revdeps failures, let me know if I missed one that I actually broke!

[camelus]

☀️ All lint checks passed 4208249

• These packages passed lint tests: ppx_deriving_yojson.1.0, ppx_deriving_yojson.1.1, ppx_deriving_yojson.2.0, ppx_deriving_yojson.2.1, ppx_deriving_yojson.2.2, ppx_deriving_yojson.2.3, ppx_deriving_yojson.2.4, ppx_deriving_yojson.3.0, ppx_deriving_yojson.3.1, ppx_deriving_yojson.3.3

---

☀️ Installability check (10326 → 10326)

[NathanReb]

Pushed some changes to hopefully make the linter happy and fix the broken builds for the older versions of ppx_deriving_yojson.

[NathanReb]

Ouh my bad, missed the camelus notification on Friday!

[NathanReb]

Hmm now there's an issue with ppx_import, I'll look into it!

[mseri]

Looks like the only remaining issue is with ppx_import for ppx_deriving_yojson.1.0 on ocaml-4.03.0.

The rest:

• nsq seems to have been fixed yesterday with nsq breaks with Lwt_log being separate, so upper bound on lwt #13394
• some old versions of ocaml-jupyter have issues with omp, probably a missing upper bound or just plain incompatibility with newer compilers
• links is not compatible with newer compilers

[kit-ty-kate]

Everything seems fine except on 4.02.3:

#=== ERROR while compiling ppx_deriving_yojson.1.0 ============================#
# context     2.0.0 | linux/x86_64 | ocaml-base-compiler.4.02.3 | file:///home/travis/build/ocaml/opam-repository
# path        ~/.opam/ocaml-base-compiler.4.02.3/.opam-switch/build/ppx_deriving_yojson.1.0
# command     ~/.opam/opam-init/hooks/sandbox.sh build ocamlbuild -classic-display -use-ocamlfind src_test/test_ppx_yojson.byte --
# exit-code   10
# env-file    ~/.opam/log/ppx_deriving_yojson-15051-03b1a4.env
# output-file ~/.opam/log/ppx_deriving_yojson-15051-03b1a4.out
### output ###
# ocamlfind ocamldep -package oUnit -package yojson -modules src_test/test_ppx_yojson.ml > src_test/test_ppx_yojson.ml.depends
# ocamlfind ocamlc -c -g -bin-annot -safe-string -ppx 'ocamlfind ppx_import/ppx_import' -ppx 'ocamlfind ppx_deriving/ppx_deriving src/ppx_deriving_yojson.cma' -package oUnit -package yojson -w @5@8@10@11@12@14@23@24@26@29@40 -I src_test -I src -o src_test/test_ppx_yojson.cmo src_test/test_ppx_yojson.ml
# + ocamlfind ocamlc -c -g -bin-annot -safe-string -ppx 'ocamlfind ppx_import/ppx_import' -ppx 'ocamlfind ppx_deriving/ppx_deriving src/ppx_deriving_yojson.cma' -package oUnit -package yojson -w @5@8@10@11@12@14@23@24@26@29@40 -I src_test -I src -o src_test/test_ppx_yojson.cmo src_test/test_ppx_yojson.ml
# ocamlfind: Package `ppx_import' not found
# File "src_test/test_ppx_yojson.ml", line 1:
# Error: Error while running external preprocessor
# Command line: ocamlfind ppx_import/ppx_import '/tmp/camlppxf2b7c6' '/tmp/camlppx741f78'
# 
# Command exited with code 2.

I'm not sure how this change introduces a failure as it seems that it was working in 3ae7241: http://check.ocamllabs.io/4.02.3/good/ppx_deriving_yojson.1.0

[kit-ty-kate]

ah, got it.. this package tests during normal compilation

[NathanReb]

Ouh sorry, got carried away, will have a look at it, thanks for the help!

[NathanReb]

I added a missing test dependency in the 1.1 package but that won't solve the issue. At this point I don't see what I could do beside removing the test build since the tests appear to be broken.

[NathanReb]

I tried running opam install -t for various versions of ppx_deriving_yojson on a local 4.02.3 switch and several of them are somehow broken so this is indeed unrelated to this PR.

I'll disable the test builds for the broken versions.

[NathanReb]

There's still an issue with 3.x which tests won't build on 4.02 for some reason but will for later versions of ocaml.

Not sure what the best solution is here, maybe add an ocaml >= 4.03 lower bound on 3.0.

Considering that the package was already broken before this PR it might be worth considering merging it. I'm happy to fix those old versions but not at the expense of the important part (ie the upper bound on yojson).

[mseri]

If it does not compile, why not adding ocaml >= 4.03?
Then I'd be happy to merge. Thanks for the help

[NathanReb]

It does compile, the tests don't ie opam install will work but opam install -t won't. That's why the CI fails from what I understood.

[kit-ty-kate]

it looks like this works. I'll let the CI complete but it seems good

[NathanReb]

I'd expect the 4.02.3 build to still fail, just on a later version, 2.x ones have being fixed indeed. If I'm wrong and it actually goes through then that's even better !

[kit-ty-kate]

I'd expect the 4.02.3 build to still fail, just on a later version, 2.x ones have being fixed indeed. If I'm wrong and it actually goes through then that's even better !

well no, the build is already finished and everything is fine on 4.02.3 ^^

[kit-ty-kate]

all green. Thanks a lot