[PATCH]: Forking benchmarks with long classpath on Windows (7)

[Aleksey Shipilev]

Thanks!

So I have a few problems with this patch: it takes a completely different route for one particular
OS, which seems odd, and complicates testing, plus (I think) it relies on relative paths to
classpath entries being the same as the path to the generated JAR, etc.

Here's my take:
  http://cr.openjdk.java.net/~shade/jmh/long-classpath.patch

Hacking this further, my lingering doubt it is a JMH place to handle this kind of failure escalated
to a firm concern. It would seems that Gradle is responsible for adding cruft to the classpath on
the platforms that are sensitive to this. In that light, the workaround is disabled by default and
can enabled with -Djmh.separateClasspathJAR=true. How about you ask Gradle and/or Gradle JMH plugin
maintainers to fix their stack, and until then use this optional workaround?

-Aleksey


On 12/21/2017 11:01 AM, Dávid Karnok wrote:
> Index: jmh-core/src/main/java/org/openjdk/jmh/runner/Runner.java
> IDEA additional info:
> Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
> <+>UTF-8
> ===================================================================
> --- jmh-core/src/main/java/org/openjdk/jmh/runner/Runner.java(revision
> 1434:1ddf31f810a3100b9433c3fedf24615e85b1d1a7)
> +++ jmh-core/src/main/java/org/openjdk/jmh/runner/Runner.java(revision 1434+:1ddf31f810a3+)
> @@ -47,6 +47,8 @@
>  import java.nio.channels.OverlappingFileLockException;
>  import java.util.*;
>  import java.util.concurrent.TimeUnit;
> +import java.util.jar.*;
> +import java.util.zip.*;
>  
>  /**
>   * Runner executes JMH benchmarks.
> @@ -826,7 +828,34 @@
>          // assemble final process command
>          command.add("-cp");
>          if (Utils.isWindows()) {
> -            command.add('"' + System.getProperty("java.class.path") + '"');
> +            try {
> +                File tmpFile = File.createTempFile("jmh-classpath-file", ".jar");
> +                tmpFile.deleteOnExit();
> +
> +                StringBuilder pw = new StringBuilder();
> +                for (String cp : System.getProperty("java.class.path").split(";")) {
> +                    pw.append("/");
> +                    pw.append(cp.replace('\\', '/').replace(" ", "%20"));
> +                    if (!cp.endsWith(".jar")) {
> +                        pw.append('/');
> +                    }
> +                    pw.append(" ");
> +                }
> +
> +                Manifest manifest = new Manifest();
> +                Attributes attributes = manifest.getMainAttributes();
> +                attributes.put(Attributes.Name.MANIFEST_VERSION, "1.0");
> +                attributes.putValue("Class-Path", pw.toString().trim());
> +
> +                try (JarOutputStream zout = new JarOutputStream(new FileOutputStream(tmpFile),
> manifest)) {
> +                    ZipEntry ze = new ZipEntry("META-INF/");
> +                    zout.putNextEntry(ze);
> +                }
> +
> +                command.add("\"" + tmpFile.getAbsolutePath() + "\"");
> +            } catch (IOException ex) {
> +                command.add('"' + System.getProperty("java.class.path") + '"');
> +            }
>          } else {
>              command.add(System.getProperty("java.class.path"));
>          }
> 
> 
> 
> 
> 
> 
> 2017-12-21 8:24 GMT+01:00 Aleksey Shipilev <shade at redhat.com <mailto:shade at redhat.com>>:
> 
>     Hi David,
> 
>     On 12/12/2017 11:36 AM, Dávid Karnok wrote:
>     > I'd like to submit a patch (attached) to JMH's
>     > org.openjdk.jmh.runner.Runner.java that creates a temporary jar file with
>     > all classpath entries on Windows so that the command line doesn't overflow.
> 
>     The patch got stripped by the mailing list, apparently. (Wrong MIME type?)
> 
>     Thanks,
>     -Aleksey
> 
> 
> 
> 
> -- 
> Best regards,
> David Karnok