fix: Propagate JNI callback failures instead of silently discarding them

Replace the deprecated `into_outcome()` pattern with jni-rs 0.22's
`resolve::<ThrowRuntimeExAndDefault>()` for scan result reporting,
FnAdapter call/close callbacks, and test initialization.

In `adapter_on_connection_state_changed`, errors were previously
swallowed with `let _ =`. Now Rust-side errors are thrown as Java
RuntimeExceptions when no JNI exception is already pending.

Author: qdot

src/droidplug/jni/mod.rs

@@ -1,6 +1,7 @@
 pub mod objects;
 
 use ::jni::{Env, EnvUnowned, NativeMethod, jni_str, native_method, objects::{JObject, Reference}};
+use ::jni::errors::ThrowRuntimeExAndDefault;
 use jni::{objects::JString, sys::jboolean};
 use std::ffi::c_void;
 use std::sync::Once;
@@ -105,11 +106,8 @@ extern "C" fn adapter_report_scan_result<'local>(
     obj: JObject<'local>,
     scan_result: JObject<'local>,
 ) {
-    let outcome = env.with_env(|env| {
-        let _ = super::adapter::adapter_report_scan_result_internal(env, &obj, scan_result);
-        Ok::<_, jni::errors::Error>(())
-    });
-    let _ = outcome.into_outcome();
+    env.with_env(|env| super::adapter::adapter_report_scan_result_internal(env, &obj, scan_result))
+        .resolve::<ThrowRuntimeExAndDefault>();
 }
 
 fn adapter_on_connection_state_changed<'local>(
@@ -118,6 +116,12 @@ fn adapter_on_connection_state_changed<'local>(
     addr: JString<'local>,
     connected: jboolean,
 ) -> jni::errors::Result<()> {
-    let _ = super::adapter::adapter_on_connection_state_changed_internal(env, &obj, addr, connected);
+    if let Err(e) =
+        super::adapter::adapter_on_connection_state_changed_internal(env, &obj, addr, connected)
+    {
+        if !env.exception_check() {
+            let _ = env.throw(format!("Rust error: {e}"));
+        }
+    }
     Ok(())
 }

src/droidplug/jni_utils/ops.rs

@@ -5,6 +5,7 @@ use ::jni::{
     jni_sig, jni_str,
     objects::{JObject, Reference},
 };
+use ::jni::errors::ThrowRuntimeExAndDefault;
 use std::sync::{Arc, Mutex};
 
 bind_java_type! {
@@ -313,7 +314,7 @@ pub(crate) extern "C" fn fn_adapter_call_internal<'local>(
 ) -> JObject<'local> {
     use std::panic::{AssertUnwindSafe, catch_unwind};
 
-    let outcome = env.with_env(|env| -> std::result::Result<JObject<'local>, jni::errors::Error> {
+    env.with_env(|env| -> std::result::Result<JObject<'local>, jni::errors::Error> {
         let arc =
             if let Ok(f) = unsafe { env.get_rust_field::<_, _, FnWrapper>(&obj1, jni_str!("data")) } {
                 AssertUnwindSafe(f.0.clone())
@@ -327,24 +328,21 @@ pub(crate) extern "C" fn fn_adapter_call_internal<'local>(
                 Ok(JObject::null())
             }
         }
-    });
-    match outcome.into_outcome() {
-        jni::Outcome::Ok(obj) => obj,
-        _ => JObject::null(),
-    }
+    })
+    .resolve::<ThrowRuntimeExAndDefault>()
 }
 
 pub(crate) extern "C" fn fn_adapter_close_internal(mut env: EnvUnowned, obj: JObject) {
     use std::panic::{AssertUnwindSafe, catch_unwind};
 
-    let outcome = env.with_env(|env| {
+    env.with_env(|env| {
         let result = catch_unwind(AssertUnwindSafe(|| {
             let _ = unsafe { env.take_rust_field::<_, _, FnWrapper>(&obj, jni_str!("data")) };
         }));
         if let Err(panic) = result {
-            let _ = super::exceptions::throw_panic(env, panic);
+            super::exceptions::throw_panic(env, panic)?;
         }
         Ok::<(), jni::errors::Error>(())
-    });
-    let _ = outcome.into_outcome();
+    })
+    .resolve::<ThrowRuntimeExAndDefault>();
 }

tests/android/rust/src/lib.rs

@@ -42,6 +42,7 @@ pub fn find_descriptor(
 
 use jni::objects::JClass;
 use jni::{Env, EnvUnowned, jni_str};
+use jni::errors::ThrowRuntimeExAndDefault;
 use std::sync::OnceLock;
 use tokio::runtime::Runtime;
 
@@ -95,11 +96,8 @@ pub extern "system" fn Java_com_nonpolynomial_btleplug_test_NativeTests_initBtle
             .with_max_level(log::LevelFilter::Debug)
             .with_tag("btleplug-test"),
     );
-    let outcome = env.with_env(|env| {
-        btleplug::platform::init(env).expect("failed to initialize btleplug");
-        Ok::<_, jni::errors::Error>(())
-    });
-    let _ = outcome.into_outcome();
+    env.with_env(|env| btleplug::platform::init(env))
+        .resolve::<ThrowRuntimeExAndDefault>();
 }
 
 // ── Test JNI exports ────────────────────────────────────────────────
@@ -111,11 +109,11 @@ macro_rules! jni_test {
     ($jni_name:ident, $test_fn:path) => {
         #[unsafe(no_mangle)]
         pub extern "system" fn $jni_name(mut env: EnvUnowned, _class: JClass) {
-            let outcome = env.with_env(|env| {
+            env.with_env(|env| {
                 run_test(env, stringify!($test_fn), $test_fn());
                 Ok::<_, jni::errors::Error>(())
-            });
-            let _ = outcome.into_outcome();
+            })
+            .resolve::<ThrowRuntimeExAndDefault>();
         }
     };
 }