Vendor the Ironwood (NU6.3) pre-release SDK, building libzcashlc from source

[j0ntz]

CHANGELOG

Does this branch warrant an entry to the CHANGELOG?

• Yes
• No

Dependencies

Upstream: ECC's unreleased Ironwood branch zcash/zcash-swift-wallet-sdk harry/ironwood-nu6.3-deps (pinned by commit), which itself pins zcash/librustzcash feat/ironwood. No published NU6.3 mobile SDK release exists yet on either platform.

Description

Asana task

DRAFT: eager integration of the Zcash Ironwood (NU6.3) network upgrade, activating July 28, 2026 at block 3,428,143. Kept as a draft until ECC publishes the audited NU6.3 mobile SDK release (expected imminently; librustzcash core shipped NU6.3 on 2026-07-09), or until we decide to ship this pre-release pin. Un-draft and repoint at the release tag when it lands.

What this does:

• Pins scripts/updateSources.ts to ECC's Ironwood integration branch commit 6668193 and builds libzcashlc from the SDK's in-repo Rust source (cargo, aarch64-apple-ios + aarch64-apple-ios-sim, cbindgen header), replacing the prebuilt libzcashlc.xcframework.zip download that has no NU6.3 release asset to point at. Restoring the prebuilt download when ECC publishes is a small revert (see git history).
• Excludes the SDK's self-contained voting backend Swift (Rust/Voting/) from vendoring: upstream defers the voting cargo feature on this branch (its zcash_voting dep does not resolve against the feat/ironwood pins), so the FFI has no zcashlc_voting_* symbols. Nothing in react-native-zcash's API uses voting. Without the exclusion the app fails to link.
• No RNZcash.swift changes needed: every consumed SDK symbol keeps a compatible signature on this branch (the 2.6.0-alpha Broadcaster redesign is confined to the separate Broadcaster protocol; the streaming createProposedTransactions convenience the bridge uses remains). The new Ironwood surface is the planOrchardDenominationSplit/DenominationPlan migration-planning API; AccountBalance gains no new pool, so the existing transparent/sapling/orchard BalanceEvent stays correct.
• Android stays on the published zcash-android-sdk 2.5.2 (NU6.2): no NU6.3 artifact exists on Maven, and building the Android SDK from source needs an NDK/cargo-ndk toolchain. Documented in android/build.gradle; bump when ECC publishes.
• Checkpoints refreshed through mainnet block 3,410,000.

Verified in Edge (edge-react-gui, iOS sim): full app build and link against the vendored Ironwood kit, launch, login, and a maestro-driven open of the funded Zcash wallet: balance 0.00798102 ZEC rendered by the NU6.3 SDK's synchronizer with sync in progress (test evidence attached below). The FFI binary was symbol-verified: 201 zcashlc_* symbols including the Ironwood migration API, zero voting symbols.

For Edge, Ironwood requires no user action and no new UI: the Orchard to Ironwood turnstile migration is handled inside the SDK's proposal logic. This upgrade is purely at the SDK layer.

Asana: https://app.asana.com/1/9976422036640/project/1213843652804305/task/1216467071647813

[j0ntz]

📸 Test evidence: Edge iOS build on the Ironwood (NU6.3) SDK

agent proof 1216467071647813 02 zcash balance ironwood sdk

agent proof 1216467071647813 03 zcash wallet detail ironwood sdk

Captured by the agent's in-app test run (build-and-test).

[j0ntz]

Superseded by EdgeApp/react-native-zcash#71, which carries the Ironwood (NU6.3) SDK plus the Orchard to Ironwood migration bridge. This draft was an initial pass at vendoring the pre-release SDK; closing in favor of that work.