From c2150aa7d2d83dfca0a292a51f6bccf7026d7515 Mon Sep 17 00:00:00 2001
From: SashegDev <gdsasheg@gmail.com>
Date: Tue, 14 Jul 2026 07:46:37 +0000
Subject: [PATCH] fix: check version jar manifest before assuming correct
 module - force overwrite vanilla jar with SRG jar if missing
 Automatic-Module-Name: minecraft - broaden SRG client jar search to multiple
 paths

---
 .../launch/LaunchCommandBuilder.java          | 79 ++++++++++++++++---
 1 file changed, 66 insertions(+), 13 deletions(-)

diff --git a/launcher/launcher/src/main/java/sashegdev/zernmc/launcher/minecraft/launch/LaunchCommandBuilder.java b/launcher/launcher/src/main/java/sashegdev/zernmc/launcher/minecraft/launch/LaunchCommandBuilder.java
index 6dd063c..2db755d 100644
--- a/launcher/launcher/src/main/java/sashegdev/zernmc/launcher/minecraft/launch/LaunchCommandBuilder.java
+++ b/launcher/launcher/src/main/java/sashegdev/zernmc/launcher/minecraft/launch/LaunchCommandBuilder.java
@@ -692,8 +692,12 @@ public class LaunchCommandBuilder {
         Path targetJar = targetDir.resolve(versionId + ".jar");
 
         if (Files.exists(targetJar) && isValidJar(targetJar)) {
-            System.out.println(ZAnsi.green("  Version jar already exists: " + targetJar));
-            return;
+            if (hasMinecraftModuleName(targetJar)) {
+                System.out.println(ZAnsi.green("  Version jar already exists with correct module name: " + targetJar));
+                return;
+            }
+            System.out.println(ZAnsi.yellow("  Version jar exists but missing Automatic-Module-Name: minecraft — overwriting with SRG jar"));
+            Files.delete(targetJar);
         }
 
         Files.createDirectories(targetDir);
@@ -725,23 +729,72 @@ public class LaunchCommandBuilder {
      */
     private Path findSrgClientJar() {
         Path librariesDir = instance.getPath().resolve("libraries");
-        Path mcDir = librariesDir.resolve("net/minecraftforge/client");
-        if (!Files.exists(mcDir)) return null;
+        if (!Files.exists(librariesDir)) return null;
 
         String mcVersion = instance.getMinecraftVersion();
-        try (var stream = Files.list(mcDir)) {
-            return stream
-                .filter(Files::isDirectory)
-                .filter(dir -> dir.getFileName().toString().startsWith(mcVersion + "-"))
-                .flatMap(dir -> {
-                    try { return Files.list(dir); } catch (Exception e) { return java.util.stream.Stream.empty(); }
-                })
-                .filter(p -> p.getFileName().toString().endsWith("-srg.jar"))
+        String[] searchDirs = {
+            "net/minecraftforge/client",
+            "net/minecraft/client",
+            "net/minecraftforge/forge"
+        };
+
+        for (String subdir : searchDirs) {
+            Path dir = librariesDir.resolve(subdir);
+            if (!Files.exists(dir)) continue;
+            try (var stream = Files.list(dir)) {
+                Path found = stream
+                    .filter(Files::isDirectory)
+                    .filter(d -> d.getFileName().toString().startsWith(mcVersion + "-"))
+                    .flatMap(d -> {
+                        try { return Files.list(d); } catch (Exception e) { return java.util.stream.Stream.empty(); }
+                    })
+                    .filter(p -> p.getFileName().toString().endsWith("-srg.jar"))
+                    .filter(this::isValidJar)
+                    .findFirst()
+                    .orElse(null);
+                if (found != null) {
+                    System.out.println(ZAnsi.green("  Found SRG client jar: " + found + " (module name: " + getModuleName(found) + ")"));
+                    return found;
+                }
+            } catch (Exception e) { /* continue */ }
+        }
+
+        // Fallback: scan libraries root for any *-srg.jar matching mcVersion
+        try {
+            Path found = java.nio.file.Files.walk(librariesDir, 5)
+                .filter(p -> p.toString().endsWith("-srg.jar"))
+                .filter(p -> p.toString().contains(mcVersion))
                 .filter(this::isValidJar)
                 .findFirst()
                 .orElse(null);
+            if (found != null) {
+                System.out.println(ZAnsi.green("  Found SRG client jar (fallback scan): " + found + " (module name: " + getModuleName(found) + ")"));
+                return found;
+            }
+        } catch (Exception e) { /* continue */ }
+
+        return null;
+    }
+
+    private String getModuleName(Path jar) {
+        try (var jarFile = new java.util.jar.JarFile(jar.toFile())) {
+            var manifest = jarFile.getManifest();
+            if (manifest == null) return "null manifest";
+            String name = manifest.getMainAttributes().getValue("Automatic-Module-Name");
+            return name != null ? name : "not set";
         } catch (Exception e) {
-            return null;
+            return "error: " + e.getMessage();
+        }
+    }
+
+    private boolean hasMinecraftModuleName(Path jar) {
+        try (var jarFile = new java.util.jar.JarFile(jar.toFile())) {
+            var manifest = jarFile.getManifest();
+            if (manifest == null) return false;
+            String moduleName = manifest.getMainAttributes().getValue("Automatic-Module-Name");
+            return "minecraft".equals(moduleName);
+        } catch (Exception e) {
+            return false;
         }
     }