Add a host-only path for refreshing the Kotlin bindings

README.md

@@ -68,6 +68,17 @@ git clone https://github.com/privkeyio/keep keep
 
 APK output: `app/build/outputs/apk/debug/app-debug.apk`. Gradle rebuilds the Rust libraries automatically when sources change. Set `KEEP_REPO` if the `keep` checkout lives elsewhere.
 
+## Typechecking against a changed core
+
+Changing keep-mobile's FFI leaves the generated Kotlin bindings stale, and regenerating them normally means a full Android cross-compile even though the Kotlin itself is platform independent. To refresh them from a plain host build instead:
+
+```bash
+KEEP_REPO=../keep ./scripts/refresh-bindings.sh
+./gradlew compileDebugKotlin
+```
+
+This needs no NDK, no `cargo-ndk` and no Android targets. It writes no `jniLibs`, so the app compiles but fails at runtime with an `UnsatisfiedLinkError` — use it while iterating on a core change, and `./gradlew assembleDebug` to run anything.
+
 Run `scripts/check-toolchain-pins.sh` to verify pinned versions are consistent across build scripts and CI workflows.
 
 # Contributing

scripts/refresh-bindings.sh

@@ -0,0 +1,76 @@
+#!/bin/bash
+# Regenerate the Kotlin FFI bindings without the Android toolchain.
+#
+# `build-rust.sh` cross-compiles keep-mobile for each Android ABI and then
+# generates bindings from one of the resulting .so files. That is what a
+# runnable APK needs, but it means a change to keep-mobile's FFI cannot be
+# typechecked here without the NDK, cargo-ndk and the Android targets, even
+# though the Kotlin it produces is platform independent.
+#
+# uniffi reads interface metadata from the library, not machine code, so a
+# plain host build carries the same metadata as a cross-compiled one. This
+# builds for the host and generates from that.
+#
+# This does NOT replace build-rust.sh. It writes no jniLibs, so the app will
+# compile and will fail at runtime with an UnsatisfiedLinkError. Use it to
+# typecheck against a changed core; use build-rust.sh to run anything.
+set -euo pipefail
+
+KEEP_REPO="${KEEP_REPO:-./keep}"
+if [ ! -d "$KEEP_REPO" ]; then
+    echo "error: KEEP_REPO path does not exist: $KEEP_REPO" >&2
+    exit 1
+fi
+KEEP_REPO="$(cd "$KEEP_REPO" && pwd)"
+SCRIPT_DIR="$(cd "$(dirname "$0")/.." && pwd)"
+RUST_PROJECT="$KEEP_REPO/keep-mobile"
+
+PROFILE="${PROFILE:-debug}"
+case "$PROFILE" in
+    debug) CARGO_PROFILE_ARGS=() ;;
+    release) CARGO_PROFILE_ARGS=(--release) ;;
+    *) echo "error: PROFILE must be debug or release, got: $PROFILE" >&2; exit 1 ;;
+esac
+
+cd "$RUST_PROJECT"
+
+echo "Building keep-mobile for the host ($PROFILE)..."
+cargo build "${CARGO_PROFILE_ARGS[@]}"
+
+# Resolve the target dir rather than assuming ../target: a workspace may set
+# CARGO_TARGET_DIR, and guessing would produce a confusing not-found on a
+# library that was built successfully.
+TARGET_DIR="$(cargo metadata --format-version 1 --no-deps | sed -nE 's/.*"target_directory":"([^"]*)".*/\1/p')"
+if [ -z "$TARGET_DIR" ]; then
+    echo "error: could not resolve cargo target directory" >&2
+    exit 1
+fi
+
+case "$(uname -s)" in
+    Darwin) LIB_NAME="libkeep_mobile.dylib" ;;
+    *)      LIB_NAME="libkeep_mobile.so" ;;
+esac
+LIB="$TARGET_DIR/$PROFILE/$LIB_NAME"
+if [ ! -f "$LIB" ]; then
+    echo "error: expected a cdylib at $LIB but it is not there." >&2
+    echo "keep-mobile must build as a cdylib for uniffi to read its metadata." >&2
+    exit 1
+fi
+
+echo "Generating Kotlin bindings from $LIB..."
+cargo run --features cli --bin uniffi-bindgen generate \
+    --library "$LIB" \
+    --language kotlin \
+    --out-dir "$SCRIPT_DIR/app/src/main/kotlin"
+
+GENERATED_KT="$SCRIPT_DIR/app/src/main/kotlin/io/privkey/keep/uniffi/keep_mobile.kt"
+if [ ! -f "$GENERATED_KT" ]; then
+    echo "error: bindings were not written to $GENERATED_KT" >&2
+    exit 1
+fi
+# Same suppression list build-rust.sh applies, so the two paths produce the
+# same file and switching between them does not show up as a diff.
+sed -i.bak 's/@file:Suppress([^)]*)/@file:Suppress("NAME_SHADOWING", "REDUNDANT_CALL_OF_CONVERSION_METHOD", "NOTHING_TO_INLINE", "UNUSED_PARAMETER", "UNUSED_EXPRESSION")/' "$GENERATED_KT"
+rm -f "$GENERATED_KT.bak"
+
+echo "Done. Bindings refreshed; no jniLibs were built, so this typechecks but does not run."