Windows: /NODEFAULTLIB:pythonXY_d.lib; Android: hoist pythonStagingRoot

Windows: Py_NO_LINK_LIB is only honored by Python 3.14+'s pyconfig.h —
3.12 and 3.13 don't guard the `pragma comment(lib, "pythonXY_d.lib")`
auto-link directive with that macro, so the Debug pragma fired regardless
and the link failed with LNK1104. Add `/NODEFAULTLIB:pythonXY_d.lib` at
link time to both serious_python_windows_plugin and flet_bridge — works
across every supported Python version. Keep the Py_NO_LINK_LIB define
too, for 3.14+ cleanliness.

Android: gradle errored with "unknown property 'pythonStagingRoot'"
because the variable was defined after the `android {}` block but
referenced inside it (in the cmake.arguments expression). Hoist the
definition above `android {}`.

Author: FeodorFitsner

src/serious_python_bridge/android/build.gradle

@@ -25,6 +25,10 @@ rootProject.allprojects {
 apply plugin: 'com.android.library'
 apply plugin: 'de.undercouch.download'
 
+// Hoisted before `android { ... }` so the cmake.arguments block below can
+// reference it. Mirrors the same expression used later for the extract task.
+def pythonStagingRoot = new File(buildDir, 'python-dist')
+
 android {
     namespace "com.flet.serious_python_bridge"
 
@@ -80,8 +84,8 @@ def pythonCacheDir = new File(
 // tarball that serious_python_android uses. We extract into a build-time
 // scratch dir (not jniLibs/) because we do NOT want to ship libpython
 // ourselves — serious_python_android ships it; we just link against it at
-// build time.
-def pythonStagingRoot = new File(buildDir, 'python-dist')
+// build time. (`pythonStagingRoot` is defined above the android{} block so
+// it can be passed into the cmake arguments.)
 
 // Single tarball contains all 4 Android ABIs' Python installs WITH headers
 // and the libpython3.so abi3 stub. The python-android-dart variant is just

src/serious_python_bridge/native/CMakeLists.txt

@@ -55,6 +55,13 @@ if(WIN32)
   # Debug builds, which makes MSVC auto-link the Debug variant of libpython
   # even though we explicitly linked python3.lib above. python-build-standalone
   # doesn't ship a Debug lib, so the link fails (LNK1104). Py_NO_LINK_LIB
-  # suppresses that pragma (Python 3.12+).
+  # suppresses the pragma in Python 3.14+, but 3.12 and 3.13 pyconfig.h don't
+  # honor it — use /NODEFAULTLIB:pythonXY_d.lib to explicitly exclude the
+  # Debug lib at link time. Works on every supported version.
   target_compile_definitions(flet_bridge PRIVATE Py_NO_LINK_LIB)
+  if(Python3_VERSION_MAJOR AND Python3_VERSION_MINOR)
+    target_link_options(flet_bridge PRIVATE
+      "/NODEFAULTLIB:python${Python3_VERSION_MAJOR}${Python3_VERSION_MINOR}_d.lib"
+    )
+  endif()
 endif()

src/serious_python_windows/windows/CMakeLists.txt

@@ -76,13 +76,19 @@ target_link_libraries(${PLUGIN_NAME} PRIVATE flutter flutter_wrapper_plugin)
 # python-build-standalone also doesn't ship a Debug variant in the same shape,
 # so a single Release Python is the consistent ABI target.
 #
-# Py_NO_LINK_LIB (set on the plugin target) suppresses pyconfig.h's
-# `#pragma comment(lib, "pythonXY_d.lib")` that fires in Debug builds, so the
-# explicit link to pythonXY.lib below is honored.
+# In Debug Flutter builds, pyconfig.h emits `#pragma comment(lib,
+# "pythonXY_d.lib")` to ask MSVC to auto-link the Debug Python lib. That lib
+# isn't shipped by python-build-standalone, so the link fails with LNK1104.
+# Py_NO_LINK_LIB (Python 3.14+) would suppress that pragma but 3.12 and 3.13
+# pyconfig.h doesn't honor it — so use /NODEFAULTLIB to explicitly exclude
+# the Debug lib request at link time. Works across all supported versions.
 target_link_libraries(${PLUGIN_NAME} PRIVATE
   "${PYTHON_PACKAGE}/libs/python${PYTHON_VERSION_NODOT}.lib"
 )
 target_compile_definitions(${PLUGIN_NAME} PRIVATE Py_NO_LINK_LIB)
+target_link_options(${PLUGIN_NAME} PRIVATE
+  "/NODEFAULTLIB:python${PYTHON_VERSION_NODOT}_d.lib"
+)
 
 # List of absolute paths to libraries that should be bundled with the plugin.
 # This list could contain prebuilt libraries, or libraries created by an