Fix NPE when launching Forge 1.13.2.

src/main/java/io/github/zekerzhayard/forgewrapper/Main.java

@@ -3,6 +3,7 @@ package io.github.zekerzhayard.forgewrapper;
 import java.io.File;
 import java.net.URL;
 import java.net.URLClassLoader;
+import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.regex.Matcher;
@@ -11,6 +12,7 @@ import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 import cpw.mods.modlauncher.Launcher;
+import io.github.zekerzhayard.forgewrapper.converter.Converter;
 import io.github.zekerzhayard.forgewrapper.installer.Download;
 
 public class Main {
@@ -18,12 +20,14 @@ public class Main {
         URL[] urls = Utils.getURLs(new ArrayList<>());
         Pattern pattern = Pattern.compile("forge-(?<mcVersion>[0-9.]+)-(?<forgeVersion>[0-9.]+)\\.jar");
         String version = "";
+        String installerFileStr = "";
         for (URL url : urls) {
             Matcher matcher = pattern.matcher(url.getFile());
             if (matcher.find() && url.getFile().endsWith(matcher.group(0))) {
                 version = matcher.group("mcVersion") + "-" + matcher.group("forgeVersion");
                 String installerUrl = String.format("https://files.minecraftforge.net/maven/net/minecraftforge/forge/%s/forge-%s-installer.jar", version, version);
-                Download.download(installerUrl, String.format("./.forgewrapper/forge-%s-installer.jar", version));
+                installerFileStr = String.format("./.forgewrapper/forge-%s-installer.jar", version);
+                Download.download(installerUrl, installerFileStr);
                 break;
             }
         }
@@ -31,7 +35,7 @@ public class Main {
         URLClassLoader ucl = URLClassLoader.newInstance(new URL[] {
             Main.class.getProtectionDomain().getCodeSource().getLocation(),
             Launcher.class.getProtectionDomain().getCodeSource().getLocation(),
-            new File(String.format("./.forgewrapper/forge-%s-installer.jar", version)).toURI().toURL()
+            new File(installerFileStr).toURI().toURL()
         }, null);
 
         Class<?> installer = ucl.loadClass("io.github.zekerzhayard.forgewrapper.installer.Installer");
@@ -39,16 +43,7 @@ public class Main {
             return;
         }
         List<String> argsList = Stream.of(args).collect(Collectors.toList());
-        argsList.add("--launchTarget");
+        argsList.addAll(Converter.getAdditionalArgs(Paths.get(installerFileStr)));
-        argsList.add("fmlclient");
-        argsList.add("--fml.forgeVersion");
-        argsList.add((String) installer.getMethod("getForgeVersion").invoke(null));
-        argsList.add("--fml.mcVersion");
-        argsList.add((String) installer.getMethod("getMcVersion").invoke(null));
-        argsList.add("--fml.forgeGroup");
-        argsList.add("net.minecraftforge");
-        argsList.add("--fml.mcpVersion");
-        argsList.add((String) installer.getMethod("getMcpVersion").invoke(null));
 
         Launcher.main(argsList.toArray(new String[0]));
     }

src/main/java/io/github/zekerzhayard/forgewrapper/converter/Converter.java

@@ -10,6 +10,7 @@ import java.nio.file.Paths;
 import java.nio.file.StandardCopyOption;
 import java.nio.file.StandardOpenOption;
 import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.zip.ZipEntry;
@@ -24,10 +25,7 @@ import com.google.gson.JsonParser;
 public class Converter {
     public static void convert(Path installerPath, Path targetDir) throws Exception {
         JsonObject installer = getInstallerJson(installerPath);
-
+        List<String> arguments = getAdditionalArgs(installer);
-        ArrayList<String> arguments = new ArrayList<>();
-
-        getElement(installer.getAsJsonObject("arguments"), "game").getAsJsonArray().iterator().forEachRemaining(je -> arguments.add(je.getAsString()));
         String mcVersion = arguments.get(arguments.indexOf("--fml.mcVersion") + 1);
         String forgeVersion = arguments.get(arguments.indexOf("--fml.forgeVersion") + 1);
         String forgeFullVersion = "forge-" + mcVersion + "-" + forgeVersion;
@@ -60,7 +58,18 @@ public class Converter {
         Files.copy(installerPath, forgeWrapperPath.resolve(forgeFullVersion + "-installer.jar"), StandardCopyOption.REPLACE_EXISTING);
     }
 
-    private static JsonObject getInstallerJson(Path installerPath) {
+    public static List<String> getAdditionalArgs(Path installerPath) {
+        JsonObject installer = getInstallerJson(installerPath);
+        return getAdditionalArgs(installer);
+    }
+
+    public static List<String> getAdditionalArgs(JsonObject installer) {
+        List<String> args = new ArrayList<>();
+        getElement(installer.getAsJsonObject("arguments"), "game").getAsJsonArray().iterator().forEachRemaining(je -> args.add(je.getAsString()));
+        return args;
+    }
+
+    public static JsonObject getInstallerJson(Path installerPath) {
         try {
             ZipFile zf = new ZipFile(installerPath.toFile());
             ZipEntry versionFile = zf.getEntry("version.json");

src/main/java/io/github/zekerzhayard/forgewrapper/installer/Installer.java

@@ -5,11 +5,9 @@ import net.minecraftforge.installer.json.Install;
 import net.minecraftforge.installer.json.Util;
 
 public class Installer {
-    private static Install install;
-
     public static boolean install() {
         ProgressCallback monitor = ProgressCallback.withOutputs(System.out);
-        install = Util.loadInstallProfile();
+        Install install = Util.loadInstallProfile();
         if (System.getProperty("java.net.preferIPv4Stack") == null) {
             System.setProperty("java.net.preferIPv4Stack", "true");
         }
@@ -20,16 +18,4 @@ public class Installer {
         monitor.message("java.net.preferIPv4Stack=" + System.getProperty("java.net.preferIPv4Stack"));
         return new ClientInstall4MultiMC(install, monitor).run(null, input -> true);
     }
-
-    public static String getForgeVersion() {
-        return install.getVersion().substring(install.getVersion().lastIndexOf("-") + 1);
-    }
-
-    public static String getMcVersion() {
-        return install.getMinecraft();
-    }
-
-    public static String getMcpVersion() {
-        return install.getData(true).get("MCP_VERSION").replace("'", "");
-    }
 }