Read WE version from manifest ourselves

(cherry picked from commit 947775b5e54aa9dd89d68ee0b382939796301902)

worldedit-core/src/main/java/com/sk89q/worldedit/WorldEdit.java

@@ -750,23 +750,9 @@ public final class WorldEdit {
             return version;
         }
 
-        Package p = WorldEdit.class.getPackage();
+        WorldEditManifest manifest = WorldEditManifest.load();
 
-        if (p == null) {
-            p = Package.getPackage("com.sk89q.worldedit");
-        }
-
-        if (p == null) {
-            version = "(unknown)";
-        } else {
-            version = p.getImplementationVersion();
-
-            if (version == null) {
-                version = "(unknown)";
-            }
-        }
-
-        return version;
+        return version = manifest.getWorldEditVersion();
     }
 
 }

worldedit-core/src/main/java/com/sk89q/worldedit/WorldEditManifest.java

@@ -0,0 +1,81 @@
+/*
+ * WorldEdit, a Minecraft world manipulation toolkit
+ * Copyright (C) sk89q <http://www.sk89q.com>
+ * Copyright (C) WorldEdit team and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.sk89q.worldedit;
+
+import javax.annotation.Nullable;
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.net.JarURLConnection;
+import java.net.URL;
+import java.util.function.Supplier;
+import java.util.jar.Attributes;
+import java.util.jar.Manifest;
+
+/**
+ * Represents WorldEdit info from the MANIFEST.MF file.
+ */
+public class WorldEditManifest {
+
+    public static final String WORLD_EDIT_VERSION = "WorldEdit-Version";
+
+    public static WorldEditManifest load() {
+        Attributes attributes = readAttributes();
+        return new WorldEditManifest(
+            readAttribute(attributes, WORLD_EDIT_VERSION, () -> "(unknown)")
+        );
+    }
+
+    private static @Nullable Attributes readAttributes() {
+        Class<WorldEditManifest> clazz = WorldEditManifest.class;
+        String className = clazz.getSimpleName() + ".class";
+        String classPath = clazz.getResource(className).toString();
+        if (!classPath.startsWith("jar")) {
+            return null;
+        }
+
+        try {
+            URL url = new URL(classPath);
+            JarURLConnection jarConnection = (JarURLConnection) url.openConnection();
+            Manifest manifest = jarConnection.getManifest();
+            return manifest.getMainAttributes();
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+    }
+
+    private static String readAttribute(@Nullable Attributes attributes, String name,
+                                        Supplier<String> defaultAction) {
+        if (attributes == null) {
+            return defaultAction.get();
+        }
+        String value = attributes.getValue(name);
+        return value != null ? value : defaultAction.get();
+    }
+
+    private final String worldEditVersion;
+
+    private WorldEditManifest(String worldEditVersion) {
+        this.worldEditVersion = worldEditVersion;
+    }
+
+    public String getWorldEditVersion() {
+        return worldEditVersion;
+    }
+}