feat: candid subtype check, during deserialization (tests)

[crusso]

builds on #3151
bumps candid dependency to see which tests are failing, if any.

[nomeata]

NB: I don't think the candid test suite has been updated to dfinity/candid#311, which I believe you are implementing.

Maybe open a PR against candid so that you can fix the test suite as you go?

Let me know if you need help running the test suite locally for faster iteration.

[crusso]

NB: I don't think the candid test suite has been updated to dfinity/candid#311, which I believe you are implementing.

Yeah, @chenyan-dfinity warned me but suggested I try bumping anyway.

Maybe open a PR against candid so that you can fix the test suite as you go?

Yeah, makes sense. But I need to do some more plumbing first (like the failing, not trapping) and other fixes. I think I'll use a global type table for all types involved in subtype checks, and then construct a fresh cache for each outer call to deserialize, shared between inner calls to sub type checks (to speed up the check for e.g. vectors of functions)

Let me know if you need help running the test suite locally for faster iteration.

I'm doing nix-build -A tests.candid? Is there another way?

[nomeata]

I'm doing nix-build -A tests.candid? Is there another way?

Yes! nix-build is usually only what you want on CI, or maybe for final checks. For incremental development it’s probably too slow.

Just run

candid-tests -i ../path/to/candid/tests

in the nix shell and

• if you make changes to motoko, run make -C src moc
• if you make changes to the tests directory, candid-tests will pick them up

You can use candid-tests -p "too long" or run just a few tests, for quick iteration

This way you don’t have to recompile more than needed as you develop, and only need to git commit at the end.