ndk-build,cargo-apk: Default target_sdk_version to 30 or lower

cargo-apk/CHANGELOG.md

@@ -2,6 +2,9 @@
 
 - Use `min_sdk_version` to select compiler target instead of `target_sdk_version` ([#197](https://github.com/rust-windowing/android-ndk-rs/pull/197)).
   See https://developer.android.com/ndk/guides/sdk-versions#minsdkversion for more details.
+- Default `target_sdk_version` to `30` or lower (instead of the highest supported SDK version by the detected NDK toolchain)
+  for more consistent interaction with Android backwards compatibility handling and its increasingly strict usage rules:
+  https://developer.android.com/distribute/best-practices/develop/target-sdk
 
 # 0.8.2 (2021-11-22)
 

cargo-apk/README.md

@@ -49,10 +49,10 @@ runtime_libs = "path/to/libs_folder"
 
 # See https://developer.android.com/guide/topics/manifest/uses-sdk-element
 #
-# Defaults to a `min_sdk_version` of 23 and `target_sdk_version` is based on the ndk's default platform.
+# Defaults to a `min_sdk_version` of 23 and `target_sdk_version` of 30 (or lower if the detected NDK doesn't support this).
 [package.metadata.android.sdk]
-min_sdk_version = 16
-target_sdk_version = 29
+min_sdk_version = 23
+target_sdk_version = 30
 max_sdk_version = 29
 
 # See https://developer.android.com/guide/topics/manifest/uses-feature-element

cargo-apk/src/apk.rs

@@ -59,13 +59,13 @@ impl<'a> ApkBuilder<'a> {
             .android_manifest
             .sdk
             .target_sdk_version
-            .get_or_insert(ndk.default_platform());
+            .get_or_insert_with(|| ndk.default_target_platform());
 
         manifest
             .android_manifest
             .application
             .debuggable
-            .get_or_insert(*cmd.profile() == Profile::Dev);
+            .get_or_insert_with(|| *cmd.profile() == Profile::Dev);
 
         Ok(Self {
             cmd,

ndk-build/CHANGELOG.md

@@ -1,5 +1,9 @@
 # Unreleased
 
+- Default `target_sdk_version` to `30` or lower (instead of the highest supported SDK version by the detected NDK toolchain)
+  for more consistent interaction with Android backwards compatibility handling and its increasingly strict usage rules:
+  https://developer.android.com/distribute/best-practices/develop/target-sdk
+
 # 0.4.3 (2021-11-22)
 
 - Provide NDK `build_tag` version from `source.properties` in the NDK root.
@@ -23,7 +27,7 @@
 
 # 0.2.0 (2021-04-20)
 
-- **Breaking:** refactored `Manifest` into a proper (de)serialization struct. `Manifest` now closely matches [`an android manifest file`](https://developer.android.com/guide/topics/manifest/manifest-element).
+- **Breaking:** refactored `Manifest` into a proper (de)serialization struct. `Manifest` now closely matches [an android manifest file](https://developer.android.com/guide/topics/manifest/manifest-element).
 - **Breaking:** removed `Config` in favor of using the new `Manifest` struct directly. Instead of using `Config::from_config` to create a `Manifest`, now you instantiate `Manifest` directly using, almost all, the same values.
 
 # 0.1.4 (2020-11-25)

ndk-build/src/apk.rs

@@ -40,7 +40,7 @@ impl ApkConfig {
             .manifest
             .sdk
             .target_sdk_version
-            .unwrap_or_else(|| self.ndk.default_platform());
+            .unwrap_or_else(|| self.ndk.default_target_platform());
         let mut aapt = self.build_tool(bin!("aapt"))?;
         aapt.arg("package")
             .arg("-f")

ndk-build/src/ndk.rs

@@ -159,10 +159,18 @@ impl Ndk {
         Ok(Command::new(dunce::canonicalize(path)?))
     }
 
-    pub fn default_platform(&self) -> u32 {
+    pub fn highest_supported_platform(&self) -> u32 {
         self.platforms().iter().max().cloned().unwrap()
     }
 
+    /// Returns platform `30` as currently [required by Google Play], or lower
+    /// when the detected SDK does not support it yet.
+    ///
+    /// [required by Google Play]: https://developer.android.com/distribute/best-practices/develop/target-sdk
+    pub fn default_target_platform(&self) -> u32 {
+        self.highest_supported_platform().min(30)
+    }
+
     pub fn platform_dir(&self, platform: u32) -> Result<PathBuf, NdkError> {
         let dir = self
             .sdk_path