try to remap patches

paperweight-core/src/main/kotlin/io/papermc/paperweight/core/taskcontainers/PatchRemapTasks.kt

@@ -83,13 +83,44 @@ open class PatchRemapTasks(
 
     val patchCraftBukkit by tasks.registering<ApplyCraftBukkitPatches> {
         // TODO temp to speed stuff up
-        //sourceJar.set(spigotDecompileJar.flatMap { it.outputJar })
-        sourceJar.set(cache.resolve("paperweight/taskCache/spigotDecompileJar.jar"))
+        sourceJar.set(spigotDecompileJar.flatMap { it.outputJar })
+        //sourceJar.set(cache.resolve("paperweight/taskCache/spigotDecompileJar.jar"))
         cleanDirPath.set("net/minecraft")
         patchDir.set(extension.patchRemap.patchDir)
         craftBukkitDir.set(extension.patchRemap.craftBukkitDir)
         outputDir.set(extension.patchRemap.patchedCraftBukkitDir)
 
         //dependsOn(cloneForPatchRemap)
     }
+
+    //val filterSpigotMojMapExcludes by tasks.registering<FilterSpigotExcludes> {
+    //    inputZip.set(spigotMojMapRemapJar.flatMap { it.outputJar })
+    //    excludesFile.set(extension.patchRemap.excludesFile)
+    //}
+//
+    //val spigotDecompileMojMapJar by tasks.registering<SpigotDecompileJar> {
+    //    inputJar.set(filterSpigotMojMapExcludes.flatMap { it.outputZip })
+    //    fernFlowerJar.set(extension.patchRemap.fernFlowerJar)
+    //    decompileCommand.set(buildDataInfo.map { it.decompileCommand })
+    //}
+
+    val remapCraftBukkitSources by tasks.registering<RemapSources> {
+        vanillaJar.set(allTasks.extractFromBundler.flatMap { it.serverJar })
+        //mojangMappedVanillaJar.set(fixJar.flatMap { it.outputJar })
+        //vanillaRemappedSpigotJar.set(filterSpigotExcludes.flatMap { it.outputZip })
+        //mappings.set(generateSpigotMappings.flatMap { it.outputMappings })
+        mappings.set(cache.resolve(SPIGOT_MOJANG_YARN_MAPPINGS))
+        //sources.set(patchCraftBukkit.flatMap { it.outputDir }) // todo temp to speed stuff up
+        sources.set(extension.patchRemap.patchedCraftBukkitDir);
+        //spigotDeps.from(downloadSpigotDependencies.map { it.outputDir.asFileTree })
+        //additionalAts.set(mergePaperAts.flatMap { it.outputFile })
+    }
+
+    // todo first try diffing against remapped mcp config source
+    // if that fails, we have to diff against spigot decompiled mojmap+yarn mapped vanilla jar
+    val diffCraftBukkitAgainstVanilla by tasks.registering<DiffCraftBukkitAgainstVanilla> {
+        craftBukkit.set(remapCraftBukkitSources.flatMap { it.sourcesOutputZip })
+        //vanilla.set(allTasks.prepareBase.flatMap { it.output })
+        vanilla.set(cache.resolve(BASE_PROJECT))
+    }
 }

paperweight-lib/src/main/kotlin/io/papermc/paperweight/tasks/patchremap/DiffCraftBukkitAgainstVanilla.kt

@@ -0,0 +1,56 @@
+package io.papermc.paperweight.tasks.patchremap
+
+import codechicken.diffpatch.cli.DiffOperation
+import io.papermc.paperweight.tasks.BaseTask
+import io.papermc.paperweight.util.defaultOutput
+import io.papermc.paperweight.util.filesMatchingRecursive
+import io.papermc.paperweight.util.path
+import org.gradle.api.file.DirectoryProperty
+import org.gradle.api.file.RegularFileProperty
+import org.gradle.api.tasks.InputDirectory
+import org.gradle.api.tasks.InputFile
+import org.gradle.api.tasks.OutputDirectory
+import org.gradle.api.tasks.TaskAction
+import java.nio.file.Files
+
+abstract class DiffCraftBukkitAgainstVanilla: BaseTask() {
+
+    @get:InputFile
+    abstract val craftBukkit: RegularFileProperty
+
+    @get:InputDirectory
+    abstract val vanilla: DirectoryProperty
+
+    @get:OutputDirectory
+    abstract val patches: RegularFileProperty
+
+    override fun init() {
+        patches.convention(defaultOutput())
+    }
+
+    @TaskAction
+    open fun run() {
+        val diffOp = DiffOperation.builder()
+            .logTo(System.out)
+            .aPath(vanilla.path.resolve("src/vanilla"))
+            .bPath(craftBukkit.path)
+            .outputPath(patches.path.resolve("dum"))
+            .verbose(false)
+            .summary(true)
+            .lineEnding("\n")
+            //.ignorePattern(ignorePattern.get())
+            .build()
+
+        diffOp.operate()
+
+        patches.path.resolve("dum").filesMatchingRecursive("*.patch").forEach { p ->
+            if (Files.readAllLines(p)[1].contains("+++ /dev/null")) {
+                Files.delete(p)
+            }
+        }
+        Files.walk(patches.path.resolve("dum"))
+            .filter { Files.isDirectory(it) }
+            .filter { it.toFile().listFiles()?.isEmpty() ?: false }
+            .forEach { Files.delete(it) }
+    }
+}