netcat does not support -U option

[dcrissman]

OS: RHEL 7.3

I don't seem to have a 'netcat' application at all, however I do have a 'ncat' that does have a -U option. As far as I can tell, it is the same application.

Could the application try both?

[WARNING] Failed to connect to SSH-agent
com.jcraft.jsch.agentproxy.AgentProxyException: netcat does not support -U option.
	at com.jcraft.jsch.agentproxy.usocket.NCUSocketFactory.<init>(NCUSocketFactory.java:70)
	at com.github.danielflower.mavenplugins.release.SshAgentSessionFactory.createDefaultJSch(SshAgentSessionFactory.java:80)
	at org.eclipse.jgit.transport.JschConfigSessionFactory.getJSch(JschConfigSessionFactory.java:261)
	at org.eclipse.jgit.transport.JschConfigSessionFactory.createSession(JschConfigSessionFactory.java:220)
	at org.eclipse.jgit.transport.JschConfigSessionFactory.createSession(JschConfigSessionFactory.java:176)
	at org.eclipse.jgit.transport.JschConfigSessionFactory.getSession(JschConfigSessionFactory.java:110)
	at org.eclipse.jgit.transport.SshTransport.getSession(SshTransport.java:137)
	at org.eclipse.jgit.transport.TransportGitSsh$SshFetchConnection.<init>(TransportGitSsh.java:264)
	at org.eclipse.jgit.transport.TransportGitSsh.openFetch(TransportGitSsh.java:162)
	at org.eclipse.jgit.api.LsRemoteCommand.execute(LsRemoteCommand.java:198)
	at org.eclipse.jgit.api.LsRemoteCommand.call(LsRemoteCommand.java:159)
	at com.github.danielflower.mavenplugins.release.LocalGitRepo.allRemoteTags(LocalGitRepo.java:186)
	at com.github.danielflower.mavenplugins.release.Reactor.getRemoteBuildNumbers(Reactor.java:120)
	at com.github.danielflower.mavenplugins.release.Reactor.fromProjects(Reactor.java:46)
	at com.github.danielflower.mavenplugins.release.NextMojo.execute(NextMojo.java:37)
	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:154)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:146)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:117)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:81)
	at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
	at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:309)
	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:194)
	at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:107)
	at org.apache.maven.cli.MavenCli.execute(MavenCli.java:993)
	at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:345)
	at org.apache.maven.cli.MavenCli.main(MavenCli.java:191)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
	at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
	at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)

[dcrissman]

Related? #26

[Zajozor]

On debian 9. The default netcat-original library does not support the -U option:

$ netcat -U
netcat: invalid option -- 'U'
nc -h for help

On the contrary, when you install the replacement - netcat-openbsd package, it works the right way. So not only BSD systems problem. It would be nice if the PR would be merged.

[tristanlins]

As a workaround, I created a wrapper /usr/local/bin/nc

#!/usr/bin/env bash

if [[ "-h" == $1 ]]; then
  exec /usr/bin/nc "$@" 1>&2
else
  exec /usr/bin/nc "$@"
fi

But fixing the library could be a better way, but currently I was unable to build it cause of very old dependencies ...

[tristanlins]

I've build a patches version.
You can find on gitlab https://gitlab.com/tristanlins/jsch-agent-proxy/-/packages/109518

Simply add the gitlab repository to your pom.xml

+    <repositories>
+        <repository>
+            <id>gitlab-maven</id>
+            <url>https://gitlab.com/api/v4/projects/17382956/packages/maven</url>
+        </repository>
+    </repositories>

And change the usocket-nc dependency version to 0.0.9-p1

     <dependencies>
         <dependency>
             <groupId>com.jcraft</groupId>
             <artifactId>jsch.agentproxy.usocket-nc</artifactId>
-            <version>0.0.9</version>
+            <version>0.0.9-p1</version>
         </dependency>
     </dependencies>