Fix logging for Android

src/serious_python/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.9.8
+
+* Fix logging on Android.
+
 ## 0.9.7
 
 * Fix app restart on Android 10.

src/serious_python/pubspec.yaml

@@ -2,7 +2,7 @@ name: serious_python
 description: A cross-platform plugin for adding embedded Python runtime to your Flutter apps.
 homepage: https://flet.dev
 repository: https://github.com/flet-dev/serious-python
-version: 0.9.7
+version: 0.9.8
 
 platforms:
   ios:

src/serious_python_android/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.9.8
+
+* Fix logging on Android.
+
 ## 0.9.7
 
 * Fix app restart on Android 10.

src/serious_python_android/android/build.gradle

@@ -1,5 +1,5 @@
 group 'com.flet.serious_python_android'
-version '0.9.7'
+version '0.9.8'
 
 def python_version = '3.12'
 

src/serious_python_android/lib/src/cpython.dart

@@ -12,8 +12,22 @@ export 'gen.dart';
 
 CPython? _cpython;
 String? _logcatForwardingError;
+Future<void> _pythonRunQueue = Future<void>.value();
+
+Future<T> _enqueuePythonRun<T>(Future<T> Function() action) {
+  final completer = Completer<T>();
+  _pythonRunQueue = _pythonRunQueue.then((_) async {
+    try {
+      completer.complete(await action());
+    } catch (e, st) {
+      completer.completeError(e, st);
+    }
+  });
+  return completer.future;
+}
+
 const _logcatInitScript = r'''
-import sys, logging
+import logging,sys
 
 # Make this init idempotent across Dart isolate restarts.
 if not getattr(sys, "__serious_python_logcat_configured__", False):
@@ -41,7 +55,7 @@ if not getattr(sys, "__serious_python_logcat_configured__", False):
     handler.setFormatter(logging.Formatter("%(levelname)s %(message)s"))
     root = logging.getLogger()
     root.handlers[:] = [handler]
-    root.setLevel(logging.DEBUG)
+    root.setLevel(logging.ERROR)
 ''';
 
 CPython getCPython(String dynamicLibPath) {
@@ -50,31 +64,33 @@ CPython getCPython(String dynamicLibPath) {
 
 Future<String> runPythonProgramFFI(bool sync, String dynamicLibPath,
     String pythonProgramPath, String script) async {
-  final receivePort = ReceivePort();
-  if (sync) {
-    // sync run
-    return await runPythonProgramInIsolate(
-        [receivePort.sendPort, dynamicLibPath, pythonProgramPath, script]);
-  } else {
-    var completer = Completer<String>();
-    // async run
-    final isolate = await Isolate.spawn(runPythonProgramInIsolate,
-        [receivePort.sendPort, dynamicLibPath, pythonProgramPath, script]);
-    receivePort.listen((message) {
-      receivePort.close();
-      isolate.kill();
-      completer.complete(message);
-    });
-    return completer.future;
-  }
+  return _enqueuePythonRun(() async {
+    spDebug(
+        "Python run start (sync=$sync, script=${script.isNotEmpty}, program=$pythonProgramPath)");
+    if (sync) {
+      // Sync run: do not involve ports (avoids GC/close races).
+      final result =
+          _runPythonProgram(dynamicLibPath, pythonProgramPath, script);
+      spDebug("Python run done (resultLength=${result.length})");
+      return result;
+    } else {
+      // Async run: use Isolate.run() to avoid manual port lifecycle issues.
+      try {
+        final result = await Isolate.run(
+            () => _runPythonProgram(dynamicLibPath, pythonProgramPath, script));
+        spDebug("Python run done (resultLength=${result.length})");
+        return result;
+      } catch (e, st) {
+        final message = "Dart error running Python: $e\n$st";
+        spDebug(message);
+        return message;
+      }
+    }
+  });
 }
 
-Future<String> runPythonProgramInIsolate(List<Object> arguments) async {
-  final sendPort = arguments[0] as SendPort;
-  final dynamicLibPath = arguments[1] as String;
-  final pythonProgramPath = arguments[2] as String;
-  final script = arguments[3] as String;
-
+String _runPythonProgram(
+    String dynamicLibPath, String pythonProgramPath, String script) {
   var programDirPath = p.dirname(pythonProgramPath);
   var programModuleName = p.basenameWithoutExtension(pythonProgramPath);
 
@@ -85,8 +101,8 @@ Future<String> runPythonProgramInIsolate(List<Object> arguments) async {
   final cpython = getCPython(dynamicLibPath);
   spDebug("CPython loaded");
   if (cpython.Py_IsInitialized() != 0) {
-    spDebug("Python already initialized, skipping execution.");
-    sendPort.send("");
+    spDebug(
+        "Python already initialized and another program is running, skipping execution.");
     return "";
   }
 
@@ -98,7 +114,6 @@ Future<String> runPythonProgramInIsolate(List<Object> arguments) async {
   final logcatSetupError = _setupLogcatForwarding(cpython);
   if (logcatSetupError != null) {
     cpython.Py_Finalize();
-    sendPort.send(logcatSetupError);
     return logcatSetupError;
   }
 
@@ -124,53 +139,88 @@ Future<String> runPythonProgramInIsolate(List<Object> arguments) async {
   cpython.Py_Finalize();
   spDebug("after Py_Finalize()");
 
-  sendPort.send(result);
-
   return result;
 }
 
 String getPythonError(CPython cpython) {
-  // get error object
-  var exPtr = cpython.PyErr_GetRaisedException();
+  final exPtr = cpython.PyErr_GetRaisedException();
+  if (exPtr == nullptr) return "Unknown Python error (no exception set).";
+
+  try {
+    final formatted = _formatPythonException(cpython, exPtr);
+    if (formatted != null && formatted.isNotEmpty) return formatted;
+
+    final fallback = _pyObjectToDartString(cpython, exPtr);
+    return fallback ?? "Unknown Python error (failed to stringify exception).";
+  } finally {
+    cpython.Py_DecRef(exPtr);
+    // Defensive: formatting can set a new Python error.
+    cpython.PyErr_Clear();
+  }
+}
 
-  // use 'traceback' module to format exception
+String? _formatPythonException(
+    CPython cpython, Pointer<PyObject> exceptionPtr) {
+  // Uses `traceback.format_exception(exc)` (Python 3.10+ signature).
   final tracebackModuleNamePtr = "traceback".toNativeUtf8();
-  var tracebackModulePtr =
+  final tracebackModulePtr =
       cpython.PyImport_ImportModule(tracebackModuleNamePtr.cast<Char>());
-  cpython.Py_DecRef(tracebackModuleNamePtr.cast());
-
-  if (tracebackModulePtr != nullptr) {
-    //spDebug("Traceback module loaded");
-
-    final formatFuncName = "format_exception".toNativeUtf8();
-    final pFormatFunc = cpython.PyObject_GetAttrString(
-        tracebackModulePtr, formatFuncName.cast());
-    cpython.Py_DecRef(tracebackModuleNamePtr.cast());
-
-    if (pFormatFunc != nullptr && cpython.PyCallable_Check(pFormatFunc) != 0) {
-      // call `traceback.format_exception()` method
-      final pArgs = cpython.PyTuple_New(1);
-      cpython.PyTuple_SetItem(pArgs, 0, exPtr);
-
-      // result is a list
-      var listPtr = cpython.PyObject_CallObject(pFormatFunc, pArgs);
-
-      // get and combine list items
-      var exLines = [];
-      var listSize = cpython.PyList_Size(listPtr);
-      for (var i = 0; i < listSize; i++) {
-        var itemObj = cpython.PyList_GetItem(listPtr, i);
-        var itemObjStr = cpython.PyObject_Str(itemObj);
-        var s =
-            cpython.PyUnicode_AsUTF8(itemObjStr).cast<Utf8>().toDartString();
-        exLines.add(s);
+  malloc.free(tracebackModuleNamePtr);
+  if (tracebackModulePtr == nullptr) return null;
+
+  try {
+    final formatFuncNamePtr = "format_exception".toNativeUtf8();
+    final formatFuncPtr = cpython.PyObject_GetAttrString(
+        tracebackModulePtr, formatFuncNamePtr.cast());
+    malloc.free(formatFuncNamePtr);
+    if (formatFuncPtr == nullptr) return null;
+
+    try {
+      if (cpython.PyCallable_Check(formatFuncPtr) == 0) return null;
+
+      final listPtr = cpython.PyObject_CallOneArg(formatFuncPtr, exceptionPtr);
+      if (listPtr == nullptr) return null;
+
+      try {
+        final listSize = cpython.PyList_Size(listPtr);
+        if (listSize < 0) return null;
+
+        final buffer = StringBuffer();
+        for (var i = 0; i < listSize; i++) {
+          final itemObj = cpython.PyList_GetItem(listPtr, i); // borrowed ref
+          if (itemObj == nullptr) continue;
+
+          final line = _pyUnicodeToDartString(cpython, itemObj) ??
+              _pyObjectToDartString(cpython, itemObj);
+          if (line == null) continue;
+          buffer.write(line);
+        }
+        return buffer.toString();
+      } finally {
+        cpython.Py_DecRef(listPtr);
       }
-      return exLines.join("");
-    } else {
-      return "traceback.format_exception() method not found.";
+    } finally {
+      cpython.Py_DecRef(formatFuncPtr);
     }
-  } else {
-    return "Error loading traceback module.";
+  } finally {
+    cpython.Py_DecRef(tracebackModulePtr);
+  }
+}
+
+String? _pyUnicodeToDartString(
+    CPython cpython, Pointer<PyObject> unicodeObjPtr) {
+  final cStr = cpython.PyUnicode_AsUTF8(unicodeObjPtr);
+  if (cStr == nullptr) return null;
+  return cStr.cast<Utf8>().toDartString();
+}
+
+String? _pyObjectToDartString(CPython cpython, Pointer<PyObject> objPtr) {
+  final strObj = cpython.PyObject_Str(objPtr);
+  if (strObj == nullptr) return null;
+  try {
+    return _pyUnicodeToDartString(cpython, strObj);
+  } finally {
+    cpython.Py_DecRef(strObj);
   }
 }
 

src/serious_python_android/pubspec.yaml

@@ -2,7 +2,7 @@ name: serious_python_android
 description: Android implementation of the serious_python plugin
 homepage: https://flet.dev
 repository: https://github.com/flet-dev/serious-python
-version: 0.9.7
+version: 0.9.8
 
 environment:
   sdk: ">=3.0.0 <4.0.0"

src/serious_python_darwin/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.9.8
+
+* Fix logging on Android.
+
 ## 0.9.7
 
 * Fix app restart on Android 10.

src/serious_python_darwin/darwin/serious_python_darwin.podspec

@@ -4,7 +4,7 @@
 #
 Pod::Spec.new do |s|
   s.name             = 'serious_python_darwin'
-  s.version          = '0.9.7'
+  s.version          = '0.9.8'
   s.summary          = 'A cross-platform plugin for adding embedded Python runtime to your Flutter apps.'
   s.description      = <<-DESC
   A cross-platform plugin for adding embedded Python runtime to your Flutter apps.

src/serious_python_darwin/pubspec.yaml

@@ -2,7 +2,7 @@ name: serious_python_darwin
 description: iOS and macOS implementations of the serious_python plugin
 homepage: https://flet.dev
 repository: https://github.com/flet-dev/serious-python
-version: 0.9.7
+version: 0.9.8
 
 environment:
   sdk: ">=3.0.0 <4.0.0"

src/serious_python_linux/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.9.8
+
+* Fix logging on Android.
+
 ## 0.9.7
 
 * Fix app restart on Android 10.

src/serious_python_linux/pubspec.yaml

@@ -2,7 +2,7 @@ name: serious_python_linux
 description: Linux implementations of the serious_python plugin
 homepage: https://flet.dev
 repository: https://github.com/flet-dev/serious-python
-version: 0.9.7
+version: 0.9.8
 
 environment:
   sdk: '>=3.1.3 <4.0.0'

src/serious_python_platform_interface/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.9.8
+
+* Fix logging on Android.
+
 ## 0.9.7
 
 * Fix app restart on Android 10.

src/serious_python_platform_interface/pubspec.yaml

@@ -2,7 +2,7 @@ name: serious_python_platform_interface
 description: A common platform interface for the serious_python plugin.
 homepage: https://flet.dev
 repository: https://github.com/flet-dev/serious-python
-version: 0.9.7
+version: 0.9.8
 
 environment:
   sdk: ">=3.0.0 <4.0.0"

src/serious_python_windows/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.9.8
+
+* Fix logging on Android.
+
 ## 0.9.7
 
 * Fix app restart on Android 10.

src/serious_python_windows/pubspec.yaml

@@ -2,7 +2,7 @@ name: serious_python_windows
 description: Windows implementations of the serious_python plugin
 homepage: https://flet.dev
 repository: https://github.com/flet-dev/serious-python
-version: 0.9.7
+version: 0.9.8
 
 environment:
   sdk: '>=3.1.3 <4.0.0'