Module host_imports 

The authoritative list of WASM host imports this crate declares.

Why this exists

A Rust extern "C" declaration becomes a WASM import only if something calls it, and it is resolved by name at module instantiation. So a crate can declare an import no host provides, and nothing notices: the SDK compiles, the host compiles, both publish, and CI stays green on both sides. It surfaces only when someone writes a contract or delegate that calls the function and watches it fail to instantiate — by which point the SDK has been telling authors to use it, in released documentation.

That is not hypothetical. freenet-stdlib 0.10.0 shipped seven delegate host imports that freenet-core 0.2.136 does not register: three withdrawn by freenet-core#5638, and four that no released node ever provided. One of the four, __frnt__delegate__subscribe_contract_checked, was documented as the preferred alternative to a function that did work. They accumulated because nothing compared the two sides. See freenet-stdlib#133.

What this gives you

DECLARED_HOST_IMPORTS is a hand-maintained list, and host_import_manifest_tests parses this crate’s own source to check that the list and the extern "C" blocks agree. Adding or removing an import therefore cannot be silent: it fails the build until someone edits this list, which puts the change in the diff a reviewer reads.

The other half lives in freenet-core

This guard proves only that the list matches what the SDK declares. It cannot see what the host registers. freenet-core should assert its own linker registration set against this constant — it is pub, and compiled into the crate freenet-core already depends on, precisely so that check needs no cross-repo file plumbing. Tracked in freenet-core#5717.

As of this release the two sets agree exactly: the 13 __frnt__delegate__* entries below are the 13 registered by WasmtimeEngine::register_host_functions at freenet-core 0.2.136.

Structs

HostImport

One WASM host import: the import module it is resolved in, and its name.

Constants

DECLARED_HOST_IMPORTS

Every WASM host import declared by this crate, sorted by (module, name).