[dkhawk]

Summary

Modernizes secrets-gradle-plugin for Gradle 8.x/9.x and Android Gradle Plugin (AGP) 8.x/9.x while preserving backwards compatibility, and adds a 3-tier automated test suite (including real-AGP Gradle TestKit functional tests).

Key Changes

• Plugin Application & Module Types (Properties are not injected if the plugin is applied before the Android plugin #62, Does not work with Android baselineprofile module #91): Replaces immediate extensions.findByType(...) lookups with project.pluginManager.withPlugin(...) across com.android.application, com.android.library, com.android.test, and com.android.dynamic-feature so plugins {} block ordering never silently no-ops.
• Unit Test & Android Test Manifest Placeholders (Merged Manifest error #41, Better support Gradle Configuration cache #89, Sample project does not work #96, Support Gradle Isolated Projects feature #104): Supports both variant.nestedComponents (AGP 8.3+/9.x) and HasUnitTest/HasAndroidTest (AGP 8.0–8.2) so :processDebugUnitTestManifest (Robolectric / isIncludeAndroidResources = true) and :processDebugAndroidTestManifest receive all secret placeholders.
• buildFeatures.buildConfig = false Guard (Warning in log : Accessing value buildConfigFields in variant has no effect as the feature buildConfig is disabled. #87): Checks project.isBuildConfigEnabled(component) before touching variant.buildConfigFields, eliminating AGP warnings when buildConfig is disabled while still injecting manifest placeholders.
• String Escaping & Sanitization (update readme to add buildConfig true which is required for BuildConfig generation #72, File leak in loadPropertiesFile() function within Extensions.kt #81, Create devcontainer.json"ghcr.io/wxw-matt/devcontainer-features/scrip… #99): Fixes String.addParenthesisIfNeeded() for empty strings ("" -> "") and escapes backslashes (\ -> \\) so Windows file paths compile cleanly in BuildConfig.java.
• 5-Level Property Precedence & Module-Local Fallback (Variant specific properties file #59): Supports defaultPropertiesFileName < propertiesFileName < ${variant.buildType}.properties < ${variant.flavorName}.properties < ${variant.name}.properties, with fallback from the root project directory to the module directory.
• Configuration Cache & Isolated Projects: Reads properties via project.providers.fileContents(...) and rootDir/projectDir so Gradle tracks secret files as configuration inputs and invalidates the configuration cache automatically when secrets rotate.
• Zero Runtime Classpath Leakage & POM Metadata (Add license, developer and scm to .pom when publishing #28): Compiles against com.android.tools.build:gradle-api with kotlin.stdlib.default.dependency=false and compileOnly(libs.kotlin.stdlib), and configures MavenPublication POM metadata.
• 3-Tier Test Suite:
  1. SecretsPluginTest (12 unit tests)
  2. SecretsPluginFunctionalTest (6 real-AGP Gradle TestKit GradleRunner end-to-end tests)
  3. :sample-app SecretsInjectionTest integration test

Fixes #28
Fixes #41
Fixes #59
Fixes #62
Fixes #81
Fixes #87
Fixes #89
Fixes #91
Fixes #96
Fixes #104