Jenkins try-catch the actual error instead of hudson.AbortException

Question

how do I get the actual exception of a failed pipeline step/plugin? I have the following pipeline code

try {
    checkout(
        scm: [ ... ]
    )
} catch (error) {
    echo error.getClass()
    echo error.getMessage()
}

which always results in

class hudson.AbortException
Error fetching remote repo 'origin'

But running without try/catch it would result in:

hudson.plugins.git.GitException: Failed to fetch from https://git.repo.git
    at hudson.plugins.git.GitSCM.fetchFrom(GitSCM.java:1003)
    at hudson.plugins.git.GitSCM.retrieveChanges(GitSCM.java:1245)
    at hudson.plugins.git.GitSCM.checkout(GitSCM.java:1309)
    at org.jenkinsci.plugins.workflow.steps.scm.SCMStep.checkout(SCMStep.java:129)
    at org.jenkinsci.plugins.workflow.steps.scm.SCMStep$StepExecutionImpl.run(SCMStep.java:97)
    at org.jenkinsci.plugins.workflow.steps.scm.SCMStep$StepExecutionImpl.run(SCMStep.java:84)
    at org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution.lambda$start$0(SynchronousNonBlockingStepExecution.java:47)
    at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
    at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
    at java.base/java.lang.Thread.run(Thread.java:829)
Caused by: hudson.plugins.git.GitException: Command "git fetch --tags --force --progress --prune --depth=1 -- https://git.repo.git +refs/heads/*:refs/remotes/origin/*" returned status code 128:
stdout: 
stderr: fatal: Unable to create '/var/jenkins_home/workspace/some_space/.git/shallow.lock': File exists.

Another git process seems to be running in this repository, e.g.
an editor opened by 'git commit'. Please make sure all processes
are terminated then try again. If it still fails, a git process
may have crashed in this repository earlier:
remove the file manually to continue.

    at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.launchCommandIn(CliGitAPIImpl.java:2734)
    at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.launchCommandWithCredentials(CliGitAPIImpl.java:2111)
    at org.jenkinsci.plugins.gitclient.CliGitAPIImpl$1.execute(CliGitAPIImpl.java:623)
    at org.jenkinsci.plugins.gitclient.RemoteGitImpl$CommandInvocationHandler$GitCommandMasterToSlaveCallable.call(RemoteGitImpl.java:158)
    at org.jenkinsci.plugins.gitclient.RemoteGitImpl$CommandInvocationHandler$GitCommandMasterToSlaveCallable.call(RemoteGitImpl.java:151)
    at hudson.remoting.UserRequest.perform(UserRequest.java:211)
    at hudson.remoting.UserRequest.perform(UserRequest.java:54)
    at hudson.remoting.Request$2.run(Request.java:377)
    at hudson.remoting.InterceptingExecutorService.lambda$wrap$0(InterceptingExecutorService.java:78)
    ... 4 more
    Suppressed: hudson.remoting.Channel$CallSiteStackTrace: Remote call to slave-lpdkwpci13vm
        at hudson.remoting.Channel.attachCallSiteStackTrace(Channel.java:1784)
        at hudson.remoting.UserRequest$ExceptionResponse.retrieve(UserRequest.java:356)
        at hudson.remoting.Channel.call(Channel.java:1000)
        at org.jenkinsci.plugins.gitclient.RemoteGitImpl$CommandInvocationHandler.execute(RemoteGitImpl.java:143)
        at jdk.internal.reflect.GeneratedMethodAccessor1484.invoke(Unknown Source)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at org.jenkinsci.plugins.gitclient.RemoteGitImpl$CommandInvocationHandler.invoke(RemoteGitImpl.java:129)
        at com.sun.proxy.$Proxy209.execute(Unknown Source)
        at hudson.plugins.git.GitSCM.fetchFrom(GitSCM.java:1001)
        at hudson.plugins.git.GitSCM.retrieveChanges(GitSCM.java:1245)
        at hudson.plugins.git.GitSCM.checkout(GitSCM.java:1309)
        at org.jenkinsci.plugins.workflow.steps.scm.SCMStep.checkout(SCMStep.java:129)
        at org.jenkinsci.plugins.workflow.steps.scm.SCMStep$StepExecutionImpl.run(SCMStep.java:97)
        at org.jenkinsci.plugins.workflow.steps.scm.SCMStep$StepExecutionImpl.run(SCMStep.java:84)
        at org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution.lambda$start$0(SynchronousNonBlockingStepExecution.java:47)
        at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
        ... 4 more

so the real exception is:

hudson.plugins.git.GitException: Command "git fetch --tags --force --progress --prune --depth=1 -- https://git.repo.git +refs/heads/*:refs/remotes/origin/*" returned status code 128:
stdout: 
stderr: fatal: Unable to create '/var/jenkins_home/workspace/some_space/.git/shallow.lock': File exists.

Is there a possibility to catch a GitException instead of hudson.AbortException or get the message from stderr.

I already tried things like error.getCause()

Answer 1

What you are referring to here is exception chaining. I don't think you can catch a specific exception in the chain. You can walk the chain to see all the exceptions. To get the last exception, the GitException, you can use this code.

Answer 2

Pipelines use regular Groovy, so you would use the normal Groovy approach for this:

try { 
   checkout() 
} catch(hudson.plugins.git.GitException e) { 
   // handle a GitException 
} catch(hudson.AbortException e) { 
   // handle an AbortException 
} finally {
   // cleanup
}