Migrate versioning to Gradle plugin and automate version bumps (#1282)

6 files changed, 180 insertions, 12 deletions

diff --git a/.github/workflows/draft_new_release.yml b/.github/workflows/draft_new_release.yml
index 74702ee4..57719eb2 100644
--- a/.github/workflows/draft_new_release.yml
+++ b/.github/workflows/draft_new_release.yml
@@ -9,32 +9,73 @@ jobs:
     name: "Draft a new release"
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@5a4ac9002d0be2fb38bd78e4b4dbde5606d7042f
-        with:
-          ref: 'release'
       - name: Extract version from milestone
         run: |
           VERSION="${{ github.event.milestone.title }}"
-          echo "RELEASE_VERSION=${VERSION/v/}" >> $GITHUB_ENV
+          RELEASE_VERSION="${VERSION/v/}"
+          # Transforms 1.13.2 to 1.13 so that we can re-use the same
+          # branch for patch releases.
+          BRANCH_VERSION="${RELEASE_VERSION:$i:-2}"
+          if [[ "${RELEASE_VERSION: -1}" == "0" ]]; then
+            CHECKOUT_REF="develop"
+          else
+            CHECKOUT_REF="release-${BRANCH_VERSION}"
+          fi
+
+          # Export variables separately so the scripting above is more legible,
+          # and we can actually use them within this block. Changes to $GITHUB_ENV
+          # only affect the next step, not the current one.
+          echo "RELEASE_VERSION=${RELEASE_VERSION}" >> $GITHUB_ENV
+          echo "CHECKOUT_REF=${CHECKOUT_REF}" >> $GITHUB_ENV
+          echo "BRANCH_VERSION=${BRANCH_VERSION}" >> $GITHUB_ENV
+          echo "PR_BASE=release-${BRANCH_VERSION}" >> $GITHUB_ENV
+          echo "PR_HEAD=release-prep" >> $GITHUB_ENV
+
+      - uses: actions/checkout@5a4ac9002d0be2fb38bd78e4b4dbde5606d7042f
+        with:
+          ref: ${{ env.CHECKOUT_REF }}
 
       - name: Update changelog
         uses: thomaseizinger/keep-a-changelog-new-release@96ebf19f2bddaf72406c84691b9c2d827da53140
         with:
-          version: ${{ env.RELEASE_VERSION }}
+          version: ${{ github.event.milestone.title }}
 
       - name: Initialize git config and commit changes
         run: |
+          # Configure name and email for Actions user
           git config user.name "GitHub Actions"
           git config user.email noreply@github.com
 
+          # It is necessary to create the $PR_BASE branch if it doesn't
+          # already exist because we want to start a PR against it.
+          if [[ "${CHECKOUT_REF}" == "develop" ]]; then
+            git branch -c develop "${PR_BASE}"
+            git push origin "${PR_BASE}"
+          fi
+
+          # Stage and commit changes to the changelog
+          git add CHANGELOG.md
+          git commit -m "CHANGELOG: bump for ${{ github.event.milestone.title }}"
+
+          # Increment the version as necessary. If we checked out develop it means
+          # that the version number is already correct, and we only need to drop the
+          # -SNAPSHOT suffix.
+          if [[ "${CHECKOUT_REF}" == "develop" ]]; then
+            ./gradlew clearPreRelease
+          else
+            ./gradlew bumpPatch
+          fi
+
+          # Commit changes to the versioning
+          git add **/version.properties
+          git commit -m "build: bump version"
+
       - name: Create Pull Request
         uses: peter-evans/create-pull-request@45c510e1f68ba052e3cd911f661a799cfb9ba3a3
         with:
           author: GitHub Actions <noreply@github.com>
-          base: release
-          body: This is an automated pull request to bump the changelog for the v${{ env.RELEASE_VERSION }} release.
-          branch: release-${{ env.RELEASE_VERSION }}
-          commit-message: "CHANGELOG: bump for ${{ env.RELEASE_VERSION }}"
-          draft: true
+          body: This is an automated pull request to bump the changelog for the ${{ github.event.milestone.title }} release.
+          base: ${{ env.PR_BASE }}
+          branch: ${{ env.PR_HEAD }}
           title: Release v${{ env.RELEASE_VERSION }}
           token: ${{ secrets.GITHUB_TOKEN }}
diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index a1b2583b..cdaca4d7 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -7,6 +7,7 @@ import com.android.build.gradle.internal.api.BaseVariantOutputImpl
 plugins {
     id("com.android.application")
     kotlin("android")
+    `versioning-plugin`
     `aps-plugin`
     `crowdin-plugin`
 }
@@ -26,8 +27,6 @@ android {
 
     defaultConfig {
         applicationId = "dev.msfjarvis.aps"
-        versionCode = 2_00_00
-        versionName = "2.0.0-SNAPSHOT"
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
     }
 
diff --git a/app/version.properties b/app/version.properties
new file mode 100644
index 00000000..c8113cb7
--- /dev/null
+++ b/app/version.properties
@@ -0,0 +1,6 @@
+#
+#This file was automatically generated by 'versioning-plugin'. DO NOT EDIT MANUALLY.
+#
+#Sun Jan 17 12:32:03 IST 2021
+versioning-plugin.versionCode=20000
+versioning-plugin.versionName=2.0.0-SNAPSHOT
diff --git a/buildSrc/build.gradle.kts b/buildSrc/build.gradle.kts
index 3b719a63..d6b6b779 100644
--- a/buildSrc/build.gradle.kts
+++ b/buildSrc/build.gradle.kts
@@ -25,6 +25,10 @@ gradlePlugin {
             id = "crowdin-plugin"
             implementationClass = "CrowdinDownloadPlugin"
         }
+        register("versioning") {
+            id = "versioning-plugin"
+            implementationClass = "VersioningPlugin"
+        }
     }
 }
 
@@ -33,4 +37,5 @@ dependencies {
     implementation(build.getValue("androidGradlePlugin"))
     implementation(build.getValue("binaryCompatibilityValidator"))
     implementation(build.getValue("downloadTaskPlugin"))
+    implementation(build.getValue("jsemver"))
 }
diff --git a/buildSrc/buildDependencies.gradle b/buildSrc/buildDependencies.gradle
index f72dce15..12da646a 100644
--- a/buildSrc/buildDependencies.gradle
+++ b/buildSrc/buildDependencies.gradle
@@ -3,6 +3,7 @@ rootProject.ext.versions = [
         kotlin                         : '1.4.21',
         binary_compatibility_validator : '0.2.4',
         download_plugin                : '4.1.1',
+        semver                         : '0.9.0',
 ]
 
 rootProject.ext.build = [
@@ -10,4 +11,5 @@ rootProject.ext.build = [
         kotlinGradlePlugin           : "org.jetbrains.kotlin:kotlin-gradle-plugin:${versions.kotlin}",
         binaryCompatibilityValidator : "org.jetbrains.kotlinx:binary-compatibility-validator:${versions.binary_compatibility_validator}",
         downloadTaskPlugin           : "de.undercouch:gradle-download-task:${versions.download_plugin}",
+        jsemver                      : "com.github.zafarkhaja:java-semver:${versions.semver}",
 ]
diff --git a/buildSrc/src/main/java/VersioningPlugin.kt b/buildSrc/src/main/java/VersioningPlugin.kt
new file mode 100644
index 00000000..7ff9709f
--- /dev/null
+++ b/buildSrc/src/main/java/VersioningPlugin.kt
@@ -0,0 +1,115 @@
+/*
+ * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+
+import com.android.build.gradle.internal.plugins.AppPlugin
+import com.github.zafarkhaja.semver.Version
+import java.io.OutputStream
+import java.util.Properties
+import org.gradle.api.Plugin
+import org.gradle.api.Project
+
+private const val VERSIONING_PROP_FILE = "version.properties"
+private const val VERSIONING_PROP_VERSION_NAME = "versioning-plugin.versionName"
+private const val VERSIONING_PROP_VERSION_CODE = "versioning-plugin.versionCode"
+private const val VERSIONING_PROP_COMMENT = """
+This file was automatically generated by 'versioning-plugin'. DO NOT EDIT MANUALLY.
+"""
+
+/**
+ * A Gradle [Plugin] that takes a [Project] with the [AppPlugin] applied and dynamically sets the
+ * versionCode and versionName properties based on values read from a [VERSIONING_PROP_FILE] file in
+ * the [Project.getBuildDir] directory. It also adds Gradle tasks to bump the major, minor, and patch
+ * versions along with one to prepare the next snapshot.
+ */
+@Suppress(
+    "UnstableApiUsage",
+    "NAME_SHADOWING"
+)
+class VersioningPlugin : Plugin<Project> {
+
+    /**
+     * Generate the Android 'versionCode' property
+     */
+    private fun Version.androidCode(): Int {
+        return majorVersion * 1_00_00 +
+            minorVersion * 1_00 +
+            patchVersion
+    }
+
+    /**
+     * Write an Android-specific variant of [this] to [stream]
+     */
+    private fun Version.writeForAndroid(stream: OutputStream) {
+        val newVersionCode = androidCode()
+        val props = Properties()
+        props.setProperty(VERSIONING_PROP_VERSION_CODE, "$newVersionCode")
+        props.setProperty(VERSIONING_PROP_VERSION_NAME, toString())
+        props.store(stream, VERSIONING_PROP_COMMENT)
+    }
+
+    /**
+     * Returns the same [Version], but with build metadata stripped.
+     */
+    private fun Version.clearPreRelease(): Version {
+        return Version.forIntegers(majorVersion, minorVersion, patchVersion)
+    }
+
+    override fun apply(project: Project) {
+        with(project) {
+            val appPlugin = requireNotNull(plugins.findPlugin(AppPlugin::class.java)) {
+                "Plugin 'com.android.application' must be applied to use this plugin"
+            }
+            val propFile = layout.projectDirectory.file(VERSIONING_PROP_FILE)
+            require(propFile.asFile.exists()) {
+                "A 'version.properties' file must exist in the project subdirectory to use this plugin"
+            }
+            val contents = providers.fileContents(propFile).asText.forUseAtConfigurationTime()
+            val versionProps = Properties().also { it.load(contents.get().byteInputStream()) }
+            val versionName = requireNotNull(versionProps.getProperty(VERSIONING_PROP_VERSION_NAME)) {
+                "version.properties must contain a '$VERSIONING_PROP_VERSION_NAME' property"
+            }
+            val versionCode = requireNotNull(versionProps.getProperty(VERSIONING_PROP_VERSION_CODE).toInt()) {
+                "version.properties must contain a '$VERSIONING_PROP_VERSION_CODE' property"
+            }
+            appPlugin.extension.defaultConfig.versionName = versionName
+            appPlugin.extension.defaultConfig.versionCode = versionCode
+            afterEvaluate {
+                val version = Version.valueOf(versionName)
+                tasks.register("clearPreRelease") {
+                    doLast {
+                        version.clearPreRelease()
+                            .writeForAndroid(propFile.asFile.outputStream())
+                    }
+                }
+                tasks.register("bumpMajor") {
+                    doLast {
+                        version.incrementMajorVersion()
+                            .writeForAndroid(propFile.asFile.outputStream())
+                    }
+                }
+                tasks.register("bumpMinor") {
+                    doLast {
+                        version.incrementMinorVersion()
+                            .writeForAndroid(propFile.asFile.outputStream())
+                    }
+                }
+                tasks.register("bumpPatch") {
+                    doLast {
+                        version.incrementPatchVersion()
+                            .writeForAndroid(propFile.asFile.outputStream())
+                    }
+                }
+                tasks.register("bumpSnapshot") {
+                    doLast {
+                        version.incrementMinorVersion()
+                            .setPreReleaseVersion("SNAPSHOT")
+                            .writeForAndroid(propFile.asFile.outputStream())
+                    }
+                }
+            }
+        }
+    }
+}