[Mono.Android] handle exceptions in RegisterNativeMembers #6672
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Context: dotnet/maui#4262 `dotnet new maui-blazor` crashes at runtime, if you do: dotnet build -t:Run -c Release You can turn *off* the linker to solve this issue: dotnet build -t:Run -c Release -p:AndroidLinkMode=None (or `PublishTrimmed=false`) The app crashes in way that you get a native crash: backtrace: #00 pc 000000000065d8fc /apex/com.android.art/lib64/libart.so (void art::StackVisitor::WalkStack<(art::StackVisitor::CountTransitions)0>(bool)+156) (BuildId: 7fbaf2a1a3317bd634b00eb90e32291e) #1 pc 000000000069b25d /apex/com.android.art/lib64/libart.so (art::Thread::GetCurrentMethod(unsigned int*, bool, bool) const+157) (BuildId: 7fbaf2a1a3317bd634b00eb90e32291e) #2 pc 0000000000430fed /apex/com.android.art/lib64/libart.so (art::JNI<false>::FindClass(_JNIEnv*, char const*)+765) (BuildId: 7fbaf2a1a3317bd634b00eb90e32291e) #3 pc 0000000000047e5a /data/app/~~0Qm6D1S0sO3f1lwfakN0PA==/com.companyname.mauiapp2-08UokVCH5k_PlbZEH_hhkA==/split_config.x86_64.apk!libmono-android.release.so (offset 0x11e000) (java_interop_jnienv_find_class+26) (BuildId: 3d04f8b946590175e97b89aee2e3b19ceed4b524) #4 pc 00000000000128ac <anonymous:41640000> After much investigation... We found that `Java.IO.InputStreamHandler.GetReadHandler()` was linked away. This is because: 1. `Mono.Android.dll` has it's Java stubs precompiled into `mono.android.jar` and `mono.android.dex`. 2. Since `Mono.Android.dll` doesn't go through `GenerateJavaStubs`, the linker has no way to know if the missing method is used -- it is only called from Java in the crashing app. To make the crash better, we need to `try-catch` *all* exceptions in `RegisterNativeMembers()` and pass them to `AndroidRuntime.RaisePendingException()`. This is because `RegisterNativeMembers()` is called directly from Java. Now the crash shows: 01-26 12:20:20.290 29264 29264 I MonoDroid: Android.Runtime.JavaProxyThrowable: Exception_WasThrown, Android.Runtime.JavaProxyThrowable 01-26 12:20:20.290 29264 29264 I MonoDroid: 01-26 12:20:20.290 29264 29264 I MonoDroid: --- End of managed Android.Runtime.JavaProxyThrowable stack trace --- 01-26 12:20:20.290 29264 29264 I MonoDroid: android.runtime.JavaProxyThrowable: System.ArgumentException: Arg_DlgtTargMeth 01-26 12:20:20.290 29264 29264 I MonoDroid: at System.Delegate.CreateDelegate(Type , Type , String , Boolean , Boolean ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at System.Delegate.CreateDelegate(Type , Type , String ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.AndroidTypeManager.RegisterNativeMembers(JniType , Type , String ) 01-26 12:20:20.290 29264 29264 I MonoDroid: --- End of stack trace from previous location --- 01-26 12:20:20.290 29264 29264 I MonoDroid: at Java.Interop.JniEnvironment.StaticMethods.CallStaticObjectMethod(JniObjectReference , JniMethodInfo , JniArgumentValue* ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.JNIEnv.CallStaticObjectMethod(IntPtr , IntPtr , JValue* ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.JNIEnv.CallStaticObjectMethod(IntPtr , IntPtr , JValue[] ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.JNIEnv.FindClass(String ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.JNIEnv.AllocObject(String ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.JNIEnv.StartCreateInstance(String , String , JValue* ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.JNIEnv.StartCreateInstance(String , String , JValue[] ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.InputStreamAdapter..ctor(Stream ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.InputStreamAdapter.ToLocalJniHandle(Stream ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Webkit.WebResourceResponse..ctor(String , String , Int32 , String , IDictionary`2 , Stream ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Microsoft.AspNetCore.Components.WebView.Maui.WebKitWebViewClient.ShouldInterceptRequest(WebView view, IWebResourceRequest request) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Webkit.WebViewClient.n_ShouldInterceptRequest_Landroid_webkit_WebView_Landroid_webkit_WebResourceRequest_(IntPtr , IntPtr , IntPtr , IntPtr ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at crc64d693e2d9159537db.WebKitWebViewClient.n_shouldInterceptRequest(Native Method) 01-26 12:20:20.290 29264 29264 I MonoDroid: at crc64d693e2d9159537db.WebKitWebViewClient.shouldInterceptRequest(WebKitWebViewClient.java:39) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Rr.a(chromium-TrichromeWebViewGoogle.apk-stable-410410686:16) 01-26 12:20:20.290 29264 29264 I MonoDroid: at org.chromium.android_webview.AwContentsBackgroundThreadClient.shouldInterceptRequestFromNative(chromium-TrichromeWebViewGoogle.apk-stable-410410686:2) 01-26 12:20:20.290 29264 29264 I MonoDroid: 01-26 12:20:20.290 29264 29264 I MonoDroid: --- End of managed Android.Runtime.JavaProxyThrowable stack trace --- 01-26 12:20:20.290 29264 29264 I MonoDroid: android.runtime.JavaProxyThrowable: System.ArgumentException: Arg_DlgtTargMeth 01-26 12:20:20.290 29264 29264 I MonoDroid: at System.Delegate.CreateDelegate(Type , Type , String , Boolean , Boolean ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at System.Delegate.CreateDelegate(Type , Type , String ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.AndroidTypeManager.RegisterNativeMembers(JniType , Type , String ) 01-26 12:20:20.290 29264 29264 I MonoDroid: --- End of stack trace from previous location --- 01-26 12:20:20.290 29264 29264 I MonoDroid: at Java.Interop.JniEnvironment.StaticMethods.CallStaticObjectMethod(JniObjectReference , JniMethodInfo , JniArgumentValue* ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.JNIEnv.CallStaticObjectMethod(IntPtr , IntPtr , JValue* ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.JNIEnv.CallStaticObjectMethod(IntPtr , IntPtr , JValue[] ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.JNIEnv.FindClass(String ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.JNIEnv.AllocObject(String ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.JNIEnv.StartCreateInstance(String , String , JValue* ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.JNIEnv.StartCreateInstance(String , String , JValue[] ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.InputStreamAdapter..ctor(Stream ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Runtime.InputStreamAdapter.ToLocalJniHandle(Stream ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Webkit.WebResourceResponse..ctor(String , String , Int32 , String , IDictionary`2 , Stream ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Microsoft.AspNetCore.Components.WebView.Maui.WebKitWebViewClient.ShouldInterceptRequest(WebView view, IWebResourceRequest request) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Android.Webkit.WebViewClient.n_ShouldInterceptRequest_Landroid_webkit_WebView_Landroid_webkit_WebResourceRequest_(IntPtr , IntPtr , IntPtr , IntPtr ) 01-26 12:20:20.290 29264 29264 I MonoDroid: at crc64d693e2d9159537db.WebKitWebViewClient.n_shouldInterceptRequest(Native Method) 01-26 12:20:20.290 29264 29264 I MonoDroid: at crc64d693e2d9159537db.WebKitWebViewClient.shouldInterceptRequest(WebKitWebViewClient.java:39) 01-26 12:20:20.290 29264 29264 I MonoDroid: at Rr.a(chromium-TrichromeWebViewGoogle.apk-stable-410410686:16) 01-26 12:20:20.290 29264 29264 I MonoDroid: at org.chromium.android_webview.AwContentsBackgroundThreadClient.shouldInterceptRequestFromNative(chromium-TrichromeWebViewGoogle.apk-stable-410410686:2) This is much easier to reason about, and will save us time in the future. A fix to the actual linker problem will be coming in another PR.
|
The diff is easier to view if you hide whitespace: https://github.com/xamarin/xamarin-android/pull/6672/files?w=1 |
Context: https://github.com/dotnet/maui/issues/4262
Context: https://github.com/xamarin/xamarin-android/pull/6675
If you run the `maui-blazor` template in a Release build:
dotnet build -t:Run -c Release
it crashes at runtime:
D monodroid-assembly: typemap: type with token 33555274 (0x200034a) in module {C7B4CC8F-7A03-4A3F-A34A-DC66EDC548B9} (Mono.Android) corresponds to Java type 'android/runtime/JavaProxyThrowable'
…
F DEBUG : backtrace:
F DEBUG : #00 pc 000000000065d8fc /apex/com.android.art/lib64/libart.so (void art::StackVisitor::WalkStack<(art::StackVisitor::CountTransitions)0>(bool)+156) (BuildId: 7fbaf2a1a3317bd634b00eb90e32291e)
F DEBUG : #01 pc 000000000069b25d /apex/com.android.art/lib64/libart.so (art::Thread::GetCurrentMethod(unsigned int*, bool, bool) const+157) (BuildId: 7fbaf2a1a3317bd634b00eb90e32291e)
F DEBUG : #02 pc 0000000000430fed /apex/com.android.art/lib64/libart.so (art::JNI<false>::FindClass(_JNIEnv*, char const*)+765) (BuildId: 7fbaf2a1a3317bd634b00eb90e32291e)
F DEBUG : #03 pc 0000000000047e5a /data/app/~~0Qm6D1S0sO3f1lwfakN0PA==/com.companyname.mauiapp2-08UokVCH5k_PlbZEH_hhkA==/split_config.x86_64.apk!libmono-android.release.so (offset 0x11e000) (java_interop_jnienv_find_class+26) (BuildId: 3d04f8b946590175e97b89aee2e3b19ceed4b524)
F DEBUG : #04 pc 00000000000128ac <anonymous:41640000>
The crash can be avoided by disabling the linker:
dotnet build -t:Run -c Release -p:AndroidLinkMode=None
# -or-
dotnet build -t:Run -c Release -p:PublishTrimmed=false
However, let us return to the crash: *why* is it crashing?
This isn't a "good debugging experience"; we have no useful context.
Lots of investigation later -- all hail printf debugging -- and we
found that the cause of the crash was an unhandled exception:
1. `Mono.Android.dll` has it's Java Callable Wrappers generated
from the *unlinked* assembly, into `mono.android.jar` and
`mono.android.dex` files. The Java Callable Wrapper for
`Android.Runtime.InputStreamAdapter` thus includes *all*
`Read()` method overloads.
2. When the app is built in Release configuration, linking is
enabled, and *some* of the `InputStreamAdapter.Read()` methods
are removed by the linker, along with the
`Java.IO.InputStream.Read()` methods that were overridden.
3. At runtime, we perform [Java Type Registration][0] for the
`Android.Runtime.InputStreamAdapter` type, which eventually calls
`AndroidTypeManager.RegisterNativeMembers()`, which eventually
attempts to *effectively* do:
Delegate.CreateDelegate (
typeof(Func<Delegate>),
typeof(InputStreamAdapter),
"GetReadHandler");
4. Because of (2), `Java.IO.InputStream.GetReadHandler()`
*does not exist*, and thus `Delegate.CreateDelegate()` throws an
`ArgumentException`.
So far, so reasonable, but…
5. `AndroidTypeManager.RegisterNativeMembers()` didn't catch any
exceptions, nor did any other method between the original Java
`Runtime.register()` invocation and
`AndroidTypeManager.RegisterNativeMembers()`. The result is that
a C# exception was "in flight", and Mono then proceeded to
*tear down the stack frame* as it unwound the callstack looking
for `catch` handlers.
At this point, the process is toast: the runtime stack is FUBAR.
This is also why the `backtrace:` is "rooted" in
`JNIEnv::FindClass()`: `JNIEnv::FindClass()` invokes Java static
constructors before returning, which is how the static constructor in
the Java Callable Wrapper for `InputStreamAdapter` called
`Runtime.register()` in the first place.
All of this makes for a miserable debugging experience.
Fixing the "original" linker issue will be done in
xamarin/xamarin-android#6675.
What we want to do *here* is improve this debugging experience, by
"wrapping" `AndroidTypeManager.RegisterNativeMembers()` in a
`try`/`catch` block, which can then *marshal the thrown exception*
back to Java. This *prevents* Mono from unwinding the callstack past
a JNI boundary, and avoids the annoying-to-debug app crash.
After this change, we get a much friendlier unhandled exception crash:
I MonoDroid: Android.Runtime.JavaProxyThrowable: Exception_WasThrown, Android.Runtime.JavaProxyThrowable
I MonoDroid:
I MonoDroid: --- End of managed Android.Runtime.JavaProxyThrowable stack trace ---
I MonoDroid: android.runtime.JavaProxyThrowable: System.ArgumentException: Arg_DlgtTargMeth
I MonoDroid: at System.Delegate.CreateDelegate(Type , Type , String , Boolean , Boolean )
I MonoDroid: at System.Delegate.CreateDelegate(Type , Type , String )
I MonoDroid: at Android.Runtime.AndroidTypeManager.RegisterNativeMembers(JniType , Type , String )
I MonoDroid: --- End of stack trace from previous location ---
I MonoDroid: at Java.Interop.JniEnvironment.StaticMethods.CallStaticObjectMethod(JniObjectReference , JniMethodInfo , JniArgumentValue* )
I MonoDroid: at Android.Runtime.JNIEnv.CallStaticObjectMethod(IntPtr , IntPtr , JValue* )
I MonoDroid: at Android.Runtime.JNIEnv.CallStaticObjectMethod(IntPtr , IntPtr , JValue[] )
I MonoDroid: at Android.Runtime.JNIEnv.FindClass(String )
I MonoDroid: at Android.Runtime.JNIEnv.AllocObject(String )
I MonoDroid: at Android.Runtime.JNIEnv.StartCreateInstance(String , String , JValue* )
I MonoDroid: at Android.Runtime.JNIEnv.StartCreateInstance(String , String , JValue[] )
I MonoDroid: at Android.Runtime.InputStreamAdapter..ctor(Stream )
I MonoDroid: at Android.Runtime.InputStreamAdapter.ToLocalJniHandle(Stream )
I MonoDroid: at Android.Webkit.WebResourceResponse..ctor(String , String , Int32 , String , IDictionary`2 , Stream )
I MonoDroid: at Microsoft.AspNetCore.Components.WebView.Maui.WebKitWebViewClient.ShouldInterceptRequest(WebView view, IWebResourceRequest request)
I MonoDroid: at Android.Webkit.WebViewClient.n_ShouldInterceptRequest_Landroid_webkit_WebView_Landroid_webkit_WebResourceRequest_(IntPtr , IntPtr , IntPtr , IntPtr )
I MonoDroid: at crc64d693e2d9159537db.WebKitWebViewClient.n_shouldInterceptRequest(Native Method)
I MonoDroid: at crc64d693e2d9159537db.WebKitWebViewClient.shouldInterceptRequest(WebKitWebViewClient.java:39)
I MonoDroid: at Rr.a(chromium-TrichromeWebViewGoogle.apk-stable-410410686:16)
I MonoDroid: at org.chromium.android_webview.AwContentsBackgroundThreadClient.shouldInterceptRequestFromNative(chromium-TrichromeWebViewGoogle.apk-stable-410410686:2)
I MonoDroid:
I MonoDroid: --- End of managed Android.Runtime.JavaProxyThrowable stack trace ---
I MonoDroid: android.runtime.JavaProxyThrowable: System.ArgumentException: Arg_DlgtTargMeth
I MonoDroid: at System.Delegate.CreateDelegate(Type , Type , String , Boolean , Boolean )
I MonoDroid: at System.Delegate.CreateDelegate(Type , Type , String )
I MonoDroid: at Android.Runtime.AndroidTypeManager.RegisterNativeMembers(JniType , Type , String )
I MonoDroid: --- End of stack trace from previous location ---
I MonoDroid: at Java.Interop.JniEnvironment.StaticMethods.CallStaticObjectMethod(JniObjectReference , JniMethodInfo , JniArgumentValue* )
I MonoDroid: at Android.Runtime.JNIEnv.CallStaticObjectMethod(IntPtr , IntPtr , JValue* )
I MonoDroid: at Android.Runtime.JNIEnv.CallStaticObjectMethod(IntPtr , IntPtr , JValue[] )
I MonoDroid: at Android.Runtime.JNIEnv.FindClass(String )
I MonoDroid: at Android.Runtime.JNIEnv.AllocObject(String )
I MonoDroid: at Android.Runtime.JNIEnv.StartCreateInstance(String , String , JValue* )
I MonoDroid: at Android.Runtime.JNIEnv.StartCreateInstance(String , String , JValue[] )
I MonoDroid: at Android.Runtime.InputStreamAdapter..ctor(Stream )
I MonoDroid: at Android.Runtime.InputStreamAdapter.ToLocalJniHandle(Stream )
I MonoDroid: at Android.Webkit.WebResourceResponse..ctor(String , String , Int32 , String , IDictionary`2 , Stream )
I MonoDroid: at Microsoft.AspNetCore.Components.WebView.Maui.WebKitWebViewClient.ShouldInterceptRequest(WebView view, IWebResourceRequest request)
I MonoDroid: at Android.Webkit.WebViewClient.n_ShouldInterceptRequest_Landroid_webkit_WebView_Landroid_webkit_WebResourceRequest_(IntPtr , IntPtr , IntPtr , IntPtr )
I MonoDroid: at crc64d693e2d9159537db.WebKitWebViewClient.n_shouldInterceptRequest(Native Method)
I MonoDroid: at crc64d693e2d9159537db.WebKitWebViewClient.shouldInterceptRequest(WebKitWebViewClient.java:39)
I MonoDroid: at Rr.a(chromium-TrichromeWebViewGoogle.apk-stable-410410686:16)
I MonoDroid: at org.chromium.android_webview.AwContentsBackgroundThreadClient.shouldInterceptRequestFromNative(chromium-TrichromeWebViewGoogle.apk-stable-410410686:2)
This is much easier to reason about, and will save us time in
the future.
[0]: https://github.com/xamarin/xamarin-android/wiki/Blueprint#java-type-registration |
jonathanpeppers
added a commit
that referenced
this pull request
Jan 27, 2022
Context: dotnet/maui#4262 Context: #6675 If you run the `maui-blazor` template in a Release build: dotnet build -t:Run -c Release it crashes at runtime: D monodroid-assembly: typemap: type with token 33555274 (0x200034a) in module {C7B4CC8F-7A03-4A3F-A34A-DC66EDC548B9} (Mono.Android) corresponds to Java type 'android/runtime/JavaProxyThrowable' … F DEBUG : backtrace: F DEBUG : #00 pc 000000000065d8fc /apex/com.android.art/lib64/libart.so (void art::StackVisitor::WalkStack<(art::StackVisitor::CountTransitions)0>(bool)+156) (BuildId: 7fbaf2a1a3317bd634b00eb90e32291e) F DEBUG : #1 pc 000000000069b25d /apex/com.android.art/lib64/libart.so (art::Thread::GetCurrentMethod(unsigned int*, bool, bool) const+157) (BuildId: 7fbaf2a1a3317bd634b00eb90e32291e) F DEBUG : #2 pc 0000000000430fed /apex/com.android.art/lib64/libart.so (art::JNI<false>::FindClass(_JNIEnv*, char const*)+765) (BuildId: 7fbaf2a1a3317bd634b00eb90e32291e) F DEBUG : #3 pc 0000000000047e5a /data/app/~~0Qm6D1S0sO3f1lwfakN0PA==/com.companyname.mauiapp2-08UokVCH5k_PlbZEH_hhkA==/split_config.x86_64.apk!libmono-android.release.so (offset 0x11e000) (java_interop_jnienv_find_class+26) (BuildId: 3d04f8b946590175e97b89aee2e3b19ceed4b524) F DEBUG : #4 pc 00000000000128ac <anonymous:41640000> The crash can be avoided by disabling the linker: dotnet build -t:Run -c Release -p:AndroidLinkMode=None # -or- dotnet build -t:Run -c Release -p:PublishTrimmed=false However, let us return to the crash: *why* is it crashing? This isn't a "good debugging experience"; we have no useful context. Lots of investigation later -- all hail printf debugging -- and we found that the cause of the crash was an unhandled exception: 1. `Mono.Android.dll` has it's Java Callable Wrappers generated from the *unlinked* assembly, into `mono.android.jar` and `mono.android.dex` files. The Java Callable Wrapper for `Android.Runtime.InputStreamAdapter` thus includes *all* `Read()` method overloads. 2. When the app is built in Release configuration, linking is enabled, and *some* of the `InputStreamAdapter.Read()` methods are removed by the linker, along with the `Java.IO.InputStream.Read()` methods that were overridden. 3. At runtime, we perform [Java Type Registration][0] for the `Android.Runtime.InputStreamAdapter` type, which eventually calls `AndroidTypeManager.RegisterNativeMembers()`, which eventually attempts to *effectively* do: Delegate.CreateDelegate ( typeof(Func<Delegate>), typeof(InputStreamAdapter), "GetReadHandler"); 4. Because of (2), `Java.IO.InputStream.GetReadHandler()` *does not exist*, and thus `Delegate.CreateDelegate()` throws an `ArgumentException`. So far, so reasonable, but… 5. `AndroidTypeManager.RegisterNativeMembers()` didn't catch any exceptions, nor did any other method between the original Java `Runtime.register()` invocation and `AndroidTypeManager.RegisterNativeMembers()`. The result is that a C# exception was "in flight", and Mono then proceeded to *tear down the stack frame* as it unwound the callstack looking for `catch` handlers. At this point, the process is toast: the runtime stack is FUBAR. This is also why the `backtrace:` is "rooted" in `JNIEnv::FindClass()`: `JNIEnv::FindClass()` invokes Java static constructors before returning, which is how the static constructor in the Java Callable Wrapper for `InputStreamAdapter` called `Runtime.register()` in the first place. All of this makes for a miserable debugging experience. Fixing the "original" linker issue will be done in #6675. This hasn't been an issue in "Classic" Xamarin.Android, presumably because the classic linker isn't as good as the net6 linker. What we want to do *here* is improve this debugging experience, by "wrapping" `AndroidTypeManager.RegisterNativeMembers()` in a `try`/`catch` block, which can then *marshal the thrown exception* back to Java. This *prevents* Mono from unwinding the callstack past a JNI boundary, and avoids the annoying-to-debug app crash. After this change, we get a much friendlier unhandled exception crash: I MonoDroid: Android.Runtime.JavaProxyThrowable: Exception_WasThrown, Android.Runtime.JavaProxyThrowable I MonoDroid: I MonoDroid: --- End of managed Android.Runtime.JavaProxyThrowable stack trace --- I MonoDroid: android.runtime.JavaProxyThrowable: System.ArgumentException: Arg_DlgtTargMeth I MonoDroid: at System.Delegate.CreateDelegate(Type , Type , String , Boolean , Boolean ) I MonoDroid: at System.Delegate.CreateDelegate(Type , Type , String ) I MonoDroid: at Android.Runtime.AndroidTypeManager.RegisterNativeMembers(JniType , Type , String ) I MonoDroid: --- End of stack trace from previous location --- I MonoDroid: at Java.Interop.JniEnvironment.StaticMethods.CallStaticObjectMethod(JniObjectReference , JniMethodInfo , JniArgumentValue* ) I MonoDroid: at Android.Runtime.JNIEnv.CallStaticObjectMethod(IntPtr , IntPtr , JValue* ) I MonoDroid: at Android.Runtime.JNIEnv.CallStaticObjectMethod(IntPtr , IntPtr , JValue[] ) I MonoDroid: at Android.Runtime.JNIEnv.FindClass(String ) I MonoDroid: at Android.Runtime.JNIEnv.AllocObject(String ) I MonoDroid: at Android.Runtime.JNIEnv.StartCreateInstance(String , String , JValue* ) I MonoDroid: at Android.Runtime.JNIEnv.StartCreateInstance(String , String , JValue[] ) I MonoDroid: at Android.Runtime.InputStreamAdapter..ctor(Stream ) I MonoDroid: at Android.Runtime.InputStreamAdapter.ToLocalJniHandle(Stream ) I MonoDroid: at Android.Webkit.WebResourceResponse..ctor(String , String , Int32 , String , IDictionary`2 , Stream ) I MonoDroid: at Microsoft.AspNetCore.Components.WebView.Maui.WebKitWebViewClient.ShouldInterceptRequest(WebView view, IWebResourceRequest request) I MonoDroid: at Android.Webkit.WebViewClient.n_ShouldInterceptRequest_Landroid_webkit_WebView_Landroid_webkit_WebResourceRequest_(IntPtr , IntPtr , IntPtr , IntPtr ) I MonoDroid: at crc64d693e2d9159537db.WebKitWebViewClient.n_shouldInterceptRequest(Native Method) I MonoDroid: at crc64d693e2d9159537db.WebKitWebViewClient.shouldInterceptRequest(WebKitWebViewClient.java:39) I MonoDroid: at Rr.a(chromium-TrichromeWebViewGoogle.apk-stable-410410686:16) I MonoDroid: at org.chromium.android_webview.AwContentsBackgroundThreadClient.shouldInterceptRequestFromNative(chromium-TrichromeWebViewGoogle.apk-stable-410410686:2) I MonoDroid: I MonoDroid: --- End of managed Android.Runtime.JavaProxyThrowable stack trace --- I MonoDroid: android.runtime.JavaProxyThrowable: System.ArgumentException: Arg_DlgtTargMeth I MonoDroid: at System.Delegate.CreateDelegate(Type , Type , String , Boolean , Boolean ) I MonoDroid: at System.Delegate.CreateDelegate(Type , Type , String ) I MonoDroid: at Android.Runtime.AndroidTypeManager.RegisterNativeMembers(JniType , Type , String ) I MonoDroid: --- End of stack trace from previous location --- I MonoDroid: at Java.Interop.JniEnvironment.StaticMethods.CallStaticObjectMethod(JniObjectReference , JniMethodInfo , JniArgumentValue* ) I MonoDroid: at Android.Runtime.JNIEnv.CallStaticObjectMethod(IntPtr , IntPtr , JValue* ) I MonoDroid: at Android.Runtime.JNIEnv.CallStaticObjectMethod(IntPtr , IntPtr , JValue[] ) I MonoDroid: at Android.Runtime.JNIEnv.FindClass(String ) I MonoDroid: at Android.Runtime.JNIEnv.AllocObject(String ) I MonoDroid: at Android.Runtime.JNIEnv.StartCreateInstance(String , String , JValue* ) I MonoDroid: at Android.Runtime.JNIEnv.StartCreateInstance(String , String , JValue[] ) I MonoDroid: at Android.Runtime.InputStreamAdapter..ctor(Stream ) I MonoDroid: at Android.Runtime.InputStreamAdapter.ToLocalJniHandle(Stream ) I MonoDroid: at Android.Webkit.WebResourceResponse..ctor(String , String , Int32 , String , IDictionary`2 , Stream ) I MonoDroid: at Microsoft.AspNetCore.Components.WebView.Maui.WebKitWebViewClient.ShouldInterceptRequest(WebView view, IWebResourceRequest request) I MonoDroid: at Android.Webkit.WebViewClient.n_ShouldInterceptRequest_Landroid_webkit_WebView_Landroid_webkit_WebResourceRequest_(IntPtr , IntPtr , IntPtr , IntPtr ) I MonoDroid: at crc64d693e2d9159537db.WebKitWebViewClient.n_shouldInterceptRequest(Native Method) I MonoDroid: at crc64d693e2d9159537db.WebKitWebViewClient.shouldInterceptRequest(WebKitWebViewClient.java:39) I MonoDroid: at Rr.a(chromium-TrichromeWebViewGoogle.apk-stable-410410686:16) I MonoDroid: at org.chromium.android_webview.AwContentsBackgroundThreadClient.shouldInterceptRequestFromNative(chromium-TrichromeWebViewGoogle.apk-stable-410410686:2) This is much easier to reason about, and will save us time in the future. [0]: https://github.com/xamarin/xamarin-android/wiki/Blueprint#java-type-registration
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Context: dotnet/maui#4262
dotnet new maui-blazorcrashes at runtime, if you do:You can turn off the linker to solve this issue:
(or
PublishTrimmed=false)The app crashes in way that you get a native crash:
After much investigation... We found that
Java.IO.InputStream.GetReadHandler()was linked away.This is because:
Mono.Android.dllhas it's Java stubs precompiled intomono.android.jarandmono.android.dex.Since
Mono.Android.dlldoesn't go throughGenerateJavaStubs,the linker has no way to know if the missing method is used -- it
is only called from Java in the crashing app.
To make the crash better, we need to
try-catchall exceptions inRegisterNativeMembers()and pass them toAndroidRuntime.RaisePendingException(). This is becauseRegisterNativeMembers()is called directly from Java.Now the crash shows:
This is much easier to reason about, and will save us time in the future.
A fix to the actual linker problem will be coming in another PR.