feat(release): unify cross-platform versioning

build.gradle.kts

@@ -1,3 +1,5 @@
+import java.util.Properties
+
 plugins {
 	// this is necessary to avoid the plugins to be loaded multiple times
 	// in each subproject's classloader
@@ -13,3 +15,74 @@ plugins {
 	alias(libs.plugins.kotlinJvm) apply false
 	alias(libs.plugins.kotlinMultiplatform) apply false
 }
+
+val versionFile = layout.projectDirectory.file("version.properties")
+val versionProperties = Properties().apply {
+	versionFile.asFile.inputStream().use(::load)
+}
+
+fun requiredVersionProperty(name: String): String =
+	versionProperties.getProperty(name)?.takeIf { it.isNotBlank() }
+		?: error("Missing $name in ${versionFile.asFile}")
+
+fun canonicalInteger(name: String, value: String, range: LongRange): Long {
+	require(value.matches(Regex("0|[1-9][0-9]*"))) {
+		"$name must be a canonical non-negative integer"
+	}
+	val number = value.toLongOrNull()
+	require(number != null && number in range) {
+		"$name must be between ${range.first} and ${range.last}"
+	}
+	return number
+}
+
+val productVersion = requiredVersionProperty("PRODUCT_VERSION")
+val productVersionMatch = Regex("(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)")
+	.matchEntire(productVersion)
+	?: error("PRODUCT_VERSION must use canonical MAJOR.MINOR.PATCH integers")
+val productVersionParts = productVersionMatch.groupValues.drop(1).map(String::toLong)
+require(productVersionParts[0] <= 65534 && productVersionParts.drop(1).all { it <= 65535 }) {
+	"PRODUCT_VERSION components exceed the supported store ranges"
+}
+
+val releaseChannel = requiredVersionProperty("RELEASE_CHANNEL")
+require(releaseChannel.matches(Regex("[a-z][a-z0-9-]*"))) {
+	"RELEASE_CHANNEL contains unsupported characters"
+}
+val androidVersionCode = canonicalInteger(
+	"ANDROID_VERSION_CODE",
+	requiredVersionProperty("ANDROID_VERSION_CODE"),
+	1L..2_100_000_000L,
+).toInt()
+val appleBuildNumber = requiredVersionProperty("APPLE_BUILD_NUMBER")
+require(appleBuildNumber.matches(Regex("[1-9][0-9]*(\\.[0-9]+){0,2}"))) {
+	"APPLE_BUILD_NUMBER must contain one to three period-separated non-negative integers and start above zero"
+}
+val windowsVersionEpoch = canonicalInteger(
+	"WINDOWS_VERSION_EPOCH",
+	requiredVersionProperty("WINDOWS_VERSION_EPOCH"),
+	1L..65535L,
+)
+val windowsMajor = productVersionParts[0] + windowsVersionEpoch
+require(windowsMajor <= 65535) {
+	"Derived Windows package major exceeds 65535"
+}
+val windowsPackageVersion =
+	"$windowsMajor.${productVersionParts[1]}.${productVersionParts[2]}.0"
+
+extra["vnidrop.productVersion"] = productVersion
+extra["vnidrop.releaseChannel"] = releaseChannel
+extra["vnidrop.androidVersionCode"] = androidVersionCode
+extra["vnidrop.appleBuildNumber"] = appleBuildNumber
+extra["vnidrop.windowsPackageVersion"] = windowsPackageVersion
+
+tasks.register("verifyVersion") {
+	group = "verification"
+	description = "Validates the canonical cross-platform application version."
+	inputs.file(versionFile)
+	inputs.property("productVersion", productVersion)
+	inputs.property("releaseChannel", releaseChannel)
+	inputs.property("androidVersionCode", androidVersionCode)
+	inputs.property("appleBuildNumber", appleBuildNumber)
+	inputs.property("windowsPackageVersion", windowsPackageVersion)
+}