Add code to handle old server jar dependencies

buildSrc/src/main/groovy/net/neoforged/minecraftdependencies/GenerateModuleMetadata.groovy

@@ -4,11 +4,18 @@ import groovy.json.JsonOutput
 import groovy.json.JsonSlurper
 import groovy.transform.CompileStatic
 import org.gradle.api.DefaultTask
+import org.gradle.api.GradleException
 import org.gradle.api.file.RegularFileProperty
 import org.gradle.api.provider.Property
-import org.gradle.api.tasks.*
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.InputFile
+import org.gradle.api.tasks.OutputFile
+import org.gradle.api.tasks.PathSensitive
+import org.gradle.api.tasks.PathSensitivity
+import org.gradle.api.tasks.TaskAction
 
 import javax.inject.Inject
+import java.util.jar.JarInputStream
 import java.util.zip.ZipFile
 
 @CompileStatic
@@ -163,6 +170,42 @@ abstract class GenerateModuleMetadata extends DefaultTask implements HasMinecraf
 
     private static final List<String> platforms = ["windows", "osx", "linux"]
 
+    private Set<String> getDirectoryListing(String artifactId) {
+        var listingFile = new File(temporaryDir, artifactId.replace(':', '-') + ".txt")
+        if (listingFile.exists()) {
+            return new HashSet<>(listingFile.readLines())
+        }
+
+        var parts = artifactId.split(":")
+        String relativeUrl
+        if (parts.length == 3) {
+            relativeUrl = parts[0].replace('.', '/') + "/" + parts[1] + "/" + parts[2] + "/" + parts[1] + "-" + parts[2] + ".jar"
+        } else {
+            relativeUrl = parts[0].replace('.', '/') + "/" + parts[1] + "/" + parts[2] + "/" + parts[1] + "-" + parts[2] + "-" + parts[3] + ".jar"
+        }
+        var url = URI.create("https://libraries.minecraft.net/" + relativeUrl).toURL()
+        println("Getting $url")
+        var folders = new HashSet<String>()
+        url.openStream().with { input ->
+            var jin = new JarInputStream(input)
+            for (var entry = jin.nextJarEntry; entry != null; entry = jin.nextJarEntry) {
+                if (!entry.name.startsWith("META-INF/") && entry.name.contains("/") && !entry.name.endsWith("/")) {
+                    folders.add(entry.name.substring(0, entry.name.lastIndexOf('/')))
+                }
+            }
+        }
+
+        println("Found ${folders.size()} folders in jar")
+
+        try (var writer = listingFile.newWriter()) {
+            for (var folder in folders) {
+                writer.writeLine(folder)
+            }
+        }
+
+        return folders
+    }
+
     private void getMcDeps(List<String> server, List<String> client, Map<String, List<String>> clientNatives) {
         Map metaJson = new JsonSlurper().parse(meta.get().asFile) as Map
         (metaJson.libraries as List<Map<String, Object>>).each { Map lib ->
@@ -188,15 +231,61 @@ abstract class GenerateModuleMetadata extends DefaultTask implements HasMinecraf
             }
         }
         try (def zf = new ZipFile(serverJar.get().getAsFile())) {
-            def entry = zf.getEntry('META-INF/libraries.list')
-            if (entry != null) {
-                try (def is = zf.getInputStream(entry)) {
+            def librariesListEntry = zf.getEntry('META-INF/libraries.list')
+            if (librariesListEntry != null) {
+                try (def is = zf.getInputStream(librariesListEntry)) {
                     is.readLines().each {
                         server.add(it.split('\t')[1])
                     }
                 }
             } else {
-                throw new RuntimeException("Could not find libraries.list inside of server.jar")
+                // This will be slow.
+
+                // List all directories found in the server jar
+                var dirnames = new HashSet<String>();
+                zf.entries().iterator().each {
+                    if (it.name.contains("/") && !it.name.endsWith("/")) {
+                        var dirname = it.name.substring(0, it.name.lastIndexOf('/'))
+                        if (
+                        // the annotation packages are re-added by NeoForm/MCP anyway and are not required to run or compile against the code
+                                dirname != "javax/annotation"
+                                        && dirname != "javax/annotation/concurrent"
+                                        && dirname != "javax/annotation/meta"
+                                        && !dirname.startsWith("net/minecraft/")
+                                        && !dirname.startsWith("data/")
+                                        && !dirname.startsWith("assets/")
+                                        && dirname != "assets"
+                                        && dirname != "data"
+                                        && dirname != "META-INF"
+                                        && !dirname.startsWith("META-INF/")) {
+                            dirnames.add(dirname)
+                        }
+                    }
+                }
+
+                var mappedDirnames = new HashSet<String>()
+                var libraries = new LinkedHashSet<String>()
+
+                // For each client library, find the list of folders contained within
+                // We need to do this in order of the declared libraries since mojang chose to fix log4j2 issues
+                // by introducing a higherpriority library that contains files from log4j2 and netty
+                for (var artifactId in client) {
+                    var folderListing = getDirectoryListing(artifactId)
+                    for (var folder in folderListing) {
+                        if (dirnames.contains(folder)) {
+                            libraries.add(artifactId)
+                            mappedDirnames.add(folder)
+                        }
+                    }
+                }
+
+                // Now report any directories in the server jar we could NOT map to a library
+                dirnames.removeAll(mappedDirnames)
+                if (!dirnames.isEmpty()) {
+                    throw new GradleException("Couldn't map the following directories from the server jar to libraries: " + dirnames)
+                }
+
+                server.addAll(libraries)
             }
         }
     }