ic-platform

Controlled Candid and executor dependencies. Enable candid for external protocol DTOs and bounded replies; enable executor for the selected CDK executor. ic_platform::Principal is unconditional; no features are enabled by default.

ic_platform::candid::{DecodeLimits, DecodeError, decode_one, decode_args, decode_exactly_one} preserves Testkit's explicit limits and typed failures. decode_one and decode_args allow bounded skipping of additional arguments; decode_exactly_one requires one actual wire argument. All select compact Candid diagnostics, which are not a redaction guarantee. Callers retain raw bytes, aggregate accounting, trust, resource policy and domain errors.

Use ic_platform::candid::contract for Candid DTO derives and encoding. Add #[candid_path("ic_platform::candid::contract")] to derived types, and #[serde(crate = "ic_platform::candid::contract::serde")] when deriving Deserialize through the boundary's Serde export. These are external protocol types, not an application-wide requirement. Principal-only users import ic_platform::Principal without selecting a feature or declaring ic_principal directly. The root and Candid contract exports have the same upstream type identity.

Enable certification for ic_platform::certification: upstream Certificate, Delegation, HashTree, Label, LookupResult, empty, fork, labeled, leaf, pruned and fork_hash, with upstream Serde support. This feature is independent of Candid and the executor. Host retains its strict bounded CBOR decoder; consumers own trust roots, authentication, budgets and leaf meanings. Neither construction nor deserialization authenticates a certificate. This centralizes dependency control without removing upstream code or promising smaller Wasm artifacts.

The contract also exports ArgumentEncoder/ArgumentDecoder for generic call helpers, Nat/Int for arbitrary-precision external values, and Reserved for partial projections. The candid feature includes upstream big-number support. Use Result<T, contract::Error> for encoding errors and DecodeError for bounded decoding failures. Existing wire labels and caller-owned limits remain unchanged.

executor exports the exact selected task/context types and operations. It owns no independent task registry. Callers must preserve context placement, callbacks and trap cleanup; native compilation does not qualify installed IC behavior. No full CDK entrypoint macros, call facade, parser, scheduler or transport exists in this initial package. Both upstream dependencies remain transitive dependencies.