Check for long paths on Windows

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

@@ -29,7 +29,6 @@ import io.papermc.paperweight.util.*
 import io.papermc.paperweight.util.constants.*
 import io.papermc.paperweight.util.data.*
 import java.io.ByteArrayOutputStream
-import java.nio.charset.Charset
 import java.nio.file.Files
 import java.nio.file.Path
 import java.util.Locale
@@ -319,9 +318,6 @@ abstract class GenerateDevBundle : DefaultTask() {
         return asString(outBytes)
     }
 
-    private fun asString(out: ByteArrayOutputStream) = String(out.toByteArray(), Charset.defaultCharset())
-        .replace(System.getProperty("line.separator"), "\n")
-
     @Suppress("SameParameterValue")
     private fun createBundleConfig(dataTargetDir: String, patchTargetDir: String): DevBundleConfig {
         return DevBundleConfig(

paperweight-lib/src/main/kotlin/io/papermc/paperweight/util/project-util.kt

@@ -50,6 +50,8 @@ fun Project.setupServerProject(
     packagesToFix: Provider<List<String>?>,
     reobfMappings: Provider<RegularFile>,
 ): ServerTasks? {
+    testPathLength(providers)
+
     if (!projectDir.exists()) {
         return null
     }

paperweight-lib/src/main/kotlin/io/papermc/paperweight/util/utils.kt

@@ -29,13 +29,15 @@ import io.papermc.paperweight.DownloadService
 import io.papermc.paperweight.PaperweightException
 import io.papermc.paperweight.tasks.*
 import io.papermc.paperweight.util.constants.*
+import java.io.ByteArrayOutputStream
 import java.io.File
 import java.io.InputStream
 import java.io.OutputStream
 import java.lang.management.ManagementFactory
 import java.lang.reflect.Type
 import java.net.URI
 import java.net.URL
+import java.nio.charset.Charset
 import java.nio.file.Path
 import java.nio.file.Paths
 import java.security.MessageDigest
@@ -45,6 +47,7 @@ import java.util.Locale
 import java.util.Optional
 import java.util.concurrent.CompletableFuture
 import java.util.concurrent.ThreadLocalRandom
+import java.util.concurrent.TimeUnit
 import java.util.concurrent.atomic.AtomicLong
 import kotlin.io.path.*
 import org.cadixdev.lorenz.merge.MergeResult
@@ -57,6 +60,7 @@ import org.gradle.api.file.RegularFile
 import org.gradle.api.file.RegularFileProperty
 import org.gradle.api.invocation.Gradle
 import org.gradle.api.logging.LogLevel
+import org.gradle.api.logging.Logging
 import org.gradle.api.plugins.JavaPluginExtension
 import org.gradle.api.provider.Property
 import org.gradle.api.provider.Provider
@@ -348,6 +352,60 @@ fun FileCollection.toJarClassProviderRoots(): List<ClassProviderRoot> = files.as
     .map { p -> ClassProviderRoot.fromJar(p) }
     .toList()
 
+fun asString(out: ByteArrayOutputStream) = String(out.toByteArray(), Charset.defaultCharset())
+    .replace(System.lineSeparator(), "\n")
+
+fun testPathLength(providers: ProviderFactory) {
+    if (!providers.gradleProperty("paperweight.windowsLongPathWarning").map { it.toBoolean() }.orElse(true).get()) {
+        return
+    }
+    if (System.getProperty("os.name").lowercase().contains("win")) {
+        val registryQuery =
+            "reg query HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Control\\FileSystem /v LongPathsEnabled"
+        val proc = ProcessBuilder()
+            .command(registryQuery.split(" "))
+            .redirectErrorStream(true)
+            .start()
+        val outBytes = ByteArrayOutputStream()
+        val outFuture = redirect(proc.inputStream, outBytes)
+        if (!proc.waitFor(10L, TimeUnit.SECONDS)) {
+            proc.destroyForcibly()
+            throw PaperweightException("Command '$registryQuery' did not finish after 10 seconds, killed process")
+        }
+        outFuture.get(500L, TimeUnit.MILLISECONDS)
+        val out = asString(outBytes)
+
+        val gitQuery = "git config --global --get core.longpaths"
+        val gitProc = ProcessBuilder()
+            .command(gitQuery.split(" "))
+            .redirectErrorStream(true)
+            .start()
+        val gitOutBytes = ByteArrayOutputStream()
+        val gitOutFuture = redirect(gitProc.inputStream, gitOutBytes)
+        if (!gitProc.waitFor(10L, TimeUnit.SECONDS)) {
+            gitProc.destroyForcibly()
+            throw PaperweightException("Command '$gitQuery' did not finish after 10 seconds, killed process")
+        }
+        gitOutFuture.get(500L, TimeUnit.MILLISECONDS)
+        val gitOut = asString(gitOutBytes)
+
+        if (out.contains("LongPathsEnabled    REG_DWORD    0x1") && gitOut.contains("true")) {
+            return
+        }
+        val logger = Logging.getLogger("paperweight-path-length-warning")
+        logger.warn(
+            """paperweight uses long paths that may exceed the Windows MAX_PATH limit depending on where the project is located.
+To avoid build failures and disable this warning, do one of the following:
+1) Enable long paths in Windows and Git:
+    Windows documentation: https://learn.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation
+    Git command: git config --global core.longpaths true
+2) Clone and build the project in WSL (this will also improve build speed)
+
+This warning can also be disabled by setting the gradle property 'paperweight.windowsLongPathWarning' to 'false'."""
+        )
+    }
+}
+
 private fun javaVersion(): Int {
     val version = System.getProperty("java.specification.version")
     val parts = version.split("\\.".toRegex()).dropLastWhile { it.isEmpty() }.toTypedArray()