JlinkPlugin: add support for huge classpaths

build.sbt

@@ -18,6 +18,8 @@ libraryDependencies ++= Seq(
   "org.apache.commons" % "commons-compress" % "1.18",
   // for jdkpackager
   "org.apache.ant" % "ant" % "1.10.5",
+  // workaround for the command line size limit
+  "com.github.eldis" % "tool-launcher" % "0.2.1",
   "org.scalatest" %% "scalatest" % "3.0.5" % Test
 )
 

src/main/scala/com/typesafe/sbt/packager/archetypes/jlink/JlinkPlugin.scala

@@ -71,7 +71,7 @@ object JlinkPlugin extends AutoPlugin {
 
       // Jdeps has a few convenient options (like --print-module-deps), but those
       // are not flexible enough - we need to parse the full output.
-      val jdepsOutput = runForOutput(run("jdeps", "--multi-release" +: javaVersion +: "-R" +: paths), log)
+      val jdepsOutput = run("jdeps", "--multi-release" +: javaVersion +: "-R" +: paths)
 
       val deps = jdepsOutput.linesIterator
       // There are headers in some of the lines - ignore those.
@@ -146,7 +146,7 @@ object JlinkPlugin extends AutoPlugin {
 
       IO.delete(outDir)
 
-      runForOutput(run("jlink", jlinkOptions.value), log)
+      run("jlink", jlinkOptions.value)
 
       outDir
     },
@@ -176,12 +176,26 @@ object JlinkPlugin extends AutoPlugin {
   private lazy val defaultJavaHome: File =
     file(sys.props.getOrElse("java.home", sys.error("no java.home")))
 
-  private def runJavaTool(jvm: File, log: Logger)(exeName: String, args: Seq[String]): ProcessBuilder = {
-    val exe = (jvm / "bin" / exeName).getAbsolutePath
+  private def runJavaTool(jvm: File, log: Logger)(toolName: String, args: Seq[String]): String = {
+    log.info("Running: " + (toolName +: args).mkString(" "))
 
-    log.info("Running: " + (exe +: args).mkString(" "))
+    val toolLauncherClass = classOf[ru.eldis.toollauncher.ToolLauncher]
+    val toolLauncherJar = file(
+      // This assumes that the code source is a file or a directory (as opposed
+      // to a remote URL) - but that should hold.
+      toolLauncherClass.getProtectionDomain.getCodeSource.getLocation.getPath
+    ).getAbsolutePath
 
-    Process(exe, args)
+    val javaExe = (jvm / "bin" / "java").getAbsolutePath
+
+    IO.withTemporaryFile(s"snp-$toolName-", "args") { argFile =>
+      IO.writeLines(argFile, args)
+
+      val argFileArg = "@" + argFile.getAbsolutePath
+      val builder = Process(Vector(javaExe, "-jar", toolLauncherJar, "-tool", toolName, argFileArg))
+
+      runForOutput(builder, log)
+    }
   }
 
   // Like `ProcessBuilder.!!`, but this logs the output in case of a non-zero

src/sbt-test/jlink/test-jlink-misc/build.sbt

@@ -62,3 +62,21 @@ val issue1247JakartaJavaModules = project
     ),
     runChecks := jlinkBuildImage.value
   )
+
+// Should succeed for large classpaths.
+val issue1266 = project
+  .enablePlugins(JlinkPlugin)
+  .settings(
+    // An arbitrary JAR with a non-platform module.
+    libraryDependencies += "com.sun.xml.fastinfoset" % "FastInfoset" % "1.2.16",
+    // A lot of "dummy" dependencies, so that the resulting classpath is over
+    // the command line limit (2MB on my machine)
+    unmanagedJars in Compile ++= {
+      def mkPath(ix: Int) = target.value / s"there-is-no-such-file-$ix.jar"
+
+      1.to(300000).map(mkPath)
+    },
+    logLevel in jlinkModules := Level.Error,
+
+    runChecks := jlinkBuildImage.value
+  )

src/sbt-test/jlink/test-jlink-misc/test

@@ -3,4 +3,5 @@
 > issue1243/runChecks
 > issue1247BadAutoModuleName/runChecks
 > issue1247ExternalModule/runChecks
-> issue1247JakartaJavaModules/runChecks
+> issue1247JakartaJavaModules/runChecks
+> issue1266/runChecks