fix: Use minimal supported JVM by default

Author: osipxd

CHANGELOG.md

@@ -11,7 +11,7 @@
   improving maintainability and compatibility with various server versions.
 - Set the default [JVM toolchain](https://docs.gradle.org/current/userguide/toolchains.html) version
   instead of setting JVM target and source compatibility to 1.8.
-  The default JVM version depends on [Paper requirements](https://docs.papermc.io/paper/getting-started#requirements).
+  By default, the minimal supported JVM version compatible with the specified `bukkit.server.version` is used.
 - Use lazy API for `bukkit.apiVersion` and `bukkit.generateMeta` properties.
 - Accept EULA using CLI parameter `-Dcom.mojang.eula.agree=true` instead of changing `eula.txt`
 

src/main/kotlin/BukkitGradlePlugin.kt

@@ -40,7 +40,7 @@ public class BukkitGradlePlugin : Plugin<Project> {
 
         extensions.configure<JavaPluginExtension> {
             toolchain {
-                languageVersion.convention(bukkit.parsedApiVersion.map(::resolveRecommendedJavaVersion))
+                languageVersion.convention(bukkit.parsedApiVersion.map(::resolveMinimalJavaVersion))
             }
         }
     }
@@ -78,11 +78,13 @@ public class BukkitGradlePlugin : Plugin<Project> {
         else -> version.toString()
     }
 
-    // See: https://docs.papermc.io/paper/getting-started#requirements
-    private fun resolveRecommendedJavaVersion(version: MinecraftVersion): JavaLanguageVersion = when {
-        version >= MinecraftVersion.V1_17_1 -> JavaLanguageVersion.of(21)
-        version >= MinecraftVersion.V1_16_5 -> JavaLanguageVersion.of(16)
-        version >= MinecraftVersion.V1_12_0 -> JavaLanguageVersion.of(11)
+    private fun resolveMinimalJavaVersion(version: MinecraftVersion): JavaLanguageVersion = when {
+        // https://minecraft.wiki/w/Java_Edition_1.20.5#General_2
+        version >= MinecraftVersion.V1_20_5 -> JavaLanguageVersion.of(21)
+        // https://minecraft.wiki/w/Java_Edition_1.18#General_2
+        version >= MinecraftVersion.V1_18_0 -> JavaLanguageVersion.of(17)
+        // https://minecraft.wiki/w/Java_Edition_1.17#General_2
+        version >= MinecraftVersion.V1_17_0 -> JavaLanguageVersion.of(16)
         else -> JavaLanguageVersion.of(8)
     }
 }

src/main/kotlin/meta/util/MinecraftVersion.kt

@@ -21,11 +21,9 @@ internal value class MinecraftVersion(private val value: Int) : Comparable<Minec
             return MinecraftVersion(major * 1_00_00 + minor * 1_00 + patch)
         }
 
-        val V1_12_0 = MinecraftVersion(1_12_00)
         val V1_13_0 = MinecraftVersion(1_13_00)
-        val V1_16_5 = MinecraftVersion(1_16_05)
         val V1_17_0 = MinecraftVersion(1_17_00)
-        val V1_17_1 = MinecraftVersion(1_17_01)
+        val V1_18_0 = MinecraftVersion(1_18_00)
         val V1_20_5 = MinecraftVersion(1_20_05)
     }
 }

src/test/groovy/ru/endlesscode/bukkitgradle/BukkitGradlePluginSpec.groovy

@@ -21,12 +21,12 @@ class BukkitGradlePluginSpec extends PluginSpecification {
 
         where:
         apiVersion | jvmVersion
-        "1.11"     | 8
-        "1.12"     | 11
-        "1.16.4"   | 11
-        "1.16.5"   | 16
+        "1.16.5"   | 8
         "1.17"     | 16
-        "1.17.1"   | 21
+        "1.17.1"   | 16
+        "1.18"     | 17
+        "1.20.4"   | 17
+        "1.20.5"   | 21
     }
 
     def "when use custom repos extension - should add repos"() {