Publish smaller Android APKs for each architecture (#2349)

* feat(android): support F-Droid ABI-split builds

* test(android): remove source-fragment ABI assertions

docs/android.md

@@ -120,6 +120,16 @@ PASEO_FDROID_BUILD=1 ./gradlew assembleRelease --no-daemon --max-workers=1 -Dorg
 
 The flag must be present for both prebuild and Gradle because Gradle starts Metro for the release bundle. Keep the source build serial and daemon-free as shown above: compiling every Expo module can exhaust memory when Gradle workers run in parallel. The profile enables source-built Expo modules, excludes the proprietary camera, Firebase notification, and Expo development-client native modules, disables EAS updates and Gradle dependency metadata, and substitutes JavaScript stubs for camera and notifications. The resulting app supports direct and pasted-link pairing but not QR scanning or push notifications.
 
+For a single-ABI APK, pass React Native's architecture property to Gradle:
+
+```bash
+PASEO_FDROID_BUILD=1 ./gradlew assembleRelease \
+  -PreactNativeArchitectures=arm64-v8a \
+  --no-daemon --max-workers=1 -Dorg.gradle.parallel=false
+```
+
+Supported values are `armeabi-v7a`, `arm64-v8a`, `x86`, and `x86_64`. The F-Droid profile filters native libraries to that ABI and changes the APK version code to `baseVersionCode * 10 + abiSuffix`, where the suffixes are ordered `1` through `4` in that same sequence. F-Droid metadata should use four build blocks with `VercodeOperation` entries `10 * %c + 1` through `10 * %c + 4` and pass the matching `reactNativeArchitectures` value in each build command. Builds without a single architecture keep the base version code.
+
 Keep the excluded npm packages installed. Normal builds use them, while the F-Droid profile removes only their Android native modules and config plugins. Paseo always applies `expo-gradle-jvmargs` with `-Xmx4096m` and `-XX:MaxMetaspaceSize=1024m` so local Expo prebuilds have enough Gradle heap whether they use precompiled AARs or source-built Expo modules.
 
 The EAS `production-apk` profile uses the large Android resource class. Release builds compile the native ABIs and run Hermes bundling in the same Gradle invocation; the default worker can exhaust its remaining memory and kill Hermes with exit code 137 even when Gradle's own heap is correctly sized.

packages/app/plugins/with-fdroid-autolinking.js

@@ -11,6 +11,51 @@ const EXCLUDED_ANDROID_MODULES = [
   "expo-dev-menu-interface",
 ];
 
+const FDROID_ABI_VERSION_CODE_BLOCK = `// Paseo F-Droid single-ABI version codes
+def paseoAbiVersionCodes = [
+    "armeabi-v7a": 1,
+    "arm64-v8a": 2,
+    "x86": 3,
+    "x86_64": 4,
+]
+def paseoArchitectures = (findProperty("reactNativeArchitectures") ?: "")
+    .toString()
+    .split(",")
+    .collect { it.trim() }
+    .findAll { !it.isEmpty() }
+
+if (paseoArchitectures.size() == 1) {
+    def paseoAbi = paseoArchitectures[0]
+    def paseoAbiVersionCode = paseoAbiVersionCodes[paseoAbi]
+    if (paseoAbiVersionCode == null) {
+        throw new GradleException("Unsupported Paseo Android ABI: " + paseoAbi)
+    }
+    android.defaultConfig.versionCode = android.defaultConfig.versionCode * 10 + paseoAbiVersionCode
+}
+`;
+
+function configureFdroidAppBuildGradle(contents) {
+  let configuredContents = contents;
+
+  if (!configuredContents.includes("dependenciesInfo {")) {
+    const androidBlock = "android {";
+    if (!configuredContents.includes(androidBlock)) {
+      throw new Error("Could not disable F-Droid dependency metadata in app/build.gradle");
+    }
+
+    configuredContents = configuredContents.replace(
+      androidBlock,
+      `${androidBlock}\n    dependenciesInfo {\n        includeInApk = false\n        includeInBundle = false\n    }`,
+    );
+  }
+
+  if (!configuredContents.includes("// Paseo F-Droid single-ABI version codes")) {
+    configuredContents = `${configuredContents.trimEnd()}\n\n${FDROID_ABI_VERSION_CODE_BLOCK}`;
+  }
+
+  return configuredContents;
+}
+
 function withFdroidAutolinking(config) {
   config = withDangerousMod(config, [
     "android",
@@ -65,19 +110,7 @@ function withFdroidAutolinking(config) {
   });
 
   return withAppBuildGradle(config, (modConfig) => {
-    if (modConfig.modResults.contents.includes("dependenciesInfo {")) {
-      return modConfig;
-    }
-
-    const androidBlock = "android {";
-    if (!modConfig.modResults.contents.includes(androidBlock)) {
-      throw new Error("Could not disable F-Droid dependency metadata in app/build.gradle");
-    }
-
-    modConfig.modResults.contents = modConfig.modResults.contents.replace(
-      androidBlock,
-      `${androidBlock}\n    dependenciesInfo {\n        includeInApk = false\n        includeInBundle = false\n    }`,
-    );
+    modConfig.modResults.contents = configureFdroidAppBuildGradle(modConfig.modResults.contents);
     return modConfig;
   });
 }