Re-enable the "next" build using the "next" host feature.

[graydon]

Just what it says -- lets us do next-builds again.

[marta-lokhova]

@graydon Is this PR still relevant? It looks like vnext runs are enabled at this point.

[graydon]

Hmm, I think it's not totally irrelevant yet. Though parts of it are no longer relevant.

We re-enabled vnext with a core-vnext feature in the stellar-core rust crate, but we do not propagate it to the next feature of soroban currently. So we still need to do something here if we want to support next-like functionality in soroban. Some amount of the next functionality in soroban was disabled/broken late in the release cycle, so we probably need to have a meeting about the strategy for re-enabling it / using it going forward; I know @dmkozh and @sisuresh have both expressed opinions!)

The key hunk in this change is this one in src/rust/Cargo.toml:

# This `next` feature switches the `curr` host (and bundled test wasms) to the
# `next` xdr definitions (and protocol number), which is something we trigger
# from core's `configure` script, and do only when building and experimenting
# with prerelease versions of core and the protocol, not something that should
# ever be released. It is therefore not related to the `prev` mechanism, which
# is for release builds that perform protocol cutovers as described above.
next = ["soroban-env-host-curr/next", "soroban-test-wasms/next"]

[sisuresh]

Hmm, I think it's not totally irrelevant yet. Though parts of it are no longer relevant.

We re-enabled vnext with a core-vnext feature in the stellar-core rust crate, but we do not propagate it to the next feature of soroban currently. So we still need to do something here if we want to support next-like functionality in soroban. Some amount of the next functionality in soroban was disabled/broken late in the release cycle, so we probably need to have a meeting about the strategy for re-enabling it / using it going forward; I know @dmkozh and @sisuresh have both expressed opinions!)

The key hunk in this change is this one in src/rust/Cargo.toml:

# This `next` feature switches the `curr` host (and bundled test wasms) to the
# `next` xdr definitions (and protocol number), which is something we trigger
# from core's `configure` script, and do only when building and experimenting
# with prerelease versions of core and the protocol, not something that should
# ever be released. It is therefore not related to the `prev` mechanism, which
# is for release builds that perform protocol cutovers as described above.
next = ["soroban-env-host-curr/next", "soroban-test-wasms/next"]

We actually made this change in a separate PR, and then removed soroban-test-wasms/next because we removed the next feature from test wasms (sorry I missed your PR back then).