Paper/patches/api/0315-Add-Git-information-to-version-command-on-startup.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Professor Bloodstone <git@bloodstone.dev>
Date: Sun, 20 Jun 2021 01:48:31 +0200
Subject: [PATCH] Add Git information to version command/on startup


diff --git a/src/main/java/io/papermc/paper/util/JarManifests.java b/src/main/java/io/papermc/paper/util/JarManifests.java
new file mode 100644
index 0000000000000000000000000000000000000000..cfd5fa044f58c8a5493f8efc08280b22c401a1da
--- /dev/null
+++ b/src/main/java/io/papermc/paper/util/JarManifests.java
@@ -0,0 +1,32 @@
+package io.papermc.paper.util;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Collections;
+import java.util.Map;
+import java.util.WeakHashMap;
+import java.util.jar.Manifest;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import org.jetbrains.annotations.ApiStatus;
+
+@ApiStatus.Internal
+public final class JarManifests {
+    private JarManifests() {
+    }
+
+    private static final Map<ClassLoader, Manifest> MANIFESTS = Collections.synchronizedMap(new WeakHashMap<>());
+
+    public static Manifest manifest(final ClassLoader loader) {
+        return MANIFESTS.computeIfAbsent(loader, classLoader -> {
+            final @Nullable InputStream stream = classLoader.getResourceAsStream("META-INF/MANIFEST.MF");
+            if (stream == null) {
+                throw new IllegalArgumentException("Provided ClassLoader does not have a manifest file in the correct location!");
+            }
+            try (stream) {
+                return new Manifest(stream);
+            } catch (final IOException ex) {
+                throw new RuntimeException("Failed to read manifest.");
+            }
+        });
+    }
+}
diff --git a/src/main/java/org/bukkit/Bukkit.java b/src/main/java/org/bukkit/Bukkit.java
index 0521781a48d326c0a4a01b920188e9ce00b51ef0..7868a54eec71f7b31d7fabf3288eb2dc62649e92 100644
--- a/src/main/java/org/bukkit/Bukkit.java
+++ b/src/main/java/org/bukkit/Bukkit.java
@@ -51,6 +51,7 @@ import org.bukkit.util.CachedServerIcon;
 import org.jetbrains.annotations.Contract;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import io.papermc.paper.util.JarManifests; // Paper
 
 /**
  * Represents the Bukkit core, for version and Server singleton handling
@@ -100,7 +101,25 @@ public final class Bukkit {
         }
 
         Bukkit.server = server;
-        server.getLogger().info("This server is running " + getName() + " version " + getVersion() + " (Implementing API version " + getBukkitVersion() + ")");
+        // Paper start - add git information
+        server.getLogger().info(getVersionMessage());
+    }
+    /**
+      * Gets message describing the version server is running.
+      *
+      * @return message describing the version server is running
+      */
+    @NotNull
+    public static String getVersionMessage() {
+        final var manifest = JarManifests.manifest(Bukkit.getServer().getClass().getClassLoader());
+        final String gitBranch = manifest.getMainAttributes().getValue("Git-Branch");
+        final String gitCommit = manifest.getMainAttributes().getValue("Git-Commit");
+        String branchMsg = " on " + gitBranch;
+        if ("master".equals(gitBranch) || "main".equals(gitBranch)) {
+            branchMsg = "";  // Don't show branch on main/master
+        }
+        return "This server is running " + getName() + " version " + getVersion() + " (Implementing API version " + getBukkitVersion() + ") (Git: " + gitCommit + branchMsg + ")";
+        // Paper end
     }
 
     /**
diff --git a/src/main/java/org/bukkit/command/defaults/VersionCommand.java b/src/main/java/org/bukkit/command/defaults/VersionCommand.java
index 4c2ddc722a9dc4011906ad9530b13fa9be1d3ff9..57a21495843f3a144cd73473cdc8781d6129b7ca 100644
--- a/src/main/java/org/bukkit/command/defaults/VersionCommand.java
+++ b/src/main/java/org/bukkit/command/defaults/VersionCommand.java
@@ -241,7 +241,7 @@ public class VersionCommand extends BukkitCommand {
     private void setVersionMessage(final @NotNull Component msg) {
         lastCheck = System.currentTimeMillis();
         final Component message = net.kyori.adventure.text.TextComponent.ofChildren(
-            Component.text("This server is running " + Bukkit.getName() + " version " + Bukkit.getVersion() + " (Implementing API version " + Bukkit.getBukkitVersion() + ")", net.kyori.adventure.text.format.NamedTextColor.WHITE),
+            Component.text(Bukkit.getVersionMessage(), net.kyori.adventure.text.format.NamedTextColor.WHITE),
             Component.newline(),
             msg
         );