Can confirm the issue, experiencing the same stacktrace with Jenkins 2.222, email-ext 2.69.

The problem only occurs when default pre-send script is non-empty.

slide_o_mix any updates on this issue?

I have been unable to reproduce the issue

I can still reproduce this with the given environment and email-ext-2.68.

I was also able to reproduce this in a docker container, in case you use a different distribution:

docker run --rm -p 127.0.0.1:8080:8080 -ti debian:stretch /bin/bash
apt-get update
apt-get install -y eatmydata
exec eatmydata bash
apt-get install -y maven git openjdk-8-jdk-headless 
cd /tmp
git clone https://github.com/jenkinsci/email-ext-plugin.git
cd email-ext-plugin/
git checkout email-ext-2.68
mvn hpi:run
# continue with step 5 from above 

I can also reproduce this with 2.69, however the ExtensionFinder.java line is different:

WARNING: Failed to instantiate Key[type=hudson.plugins.emailext.ExtendedEmailPublisherDescriptor, annotation=[none]]; skipping this component
com.google.inject.ProvisionException: Unable to provision, see the following errors:
1) Tried proxying hudson.plugins.emailext.ExtendedEmailPublisherDescriptor to support a circular dependency, but it is not an interface.
1 error
 at com.google.inject.internal.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:52)
 at com.google.inject.internal.SingletonScope$1.get(SingletonScope.java:145)
 at hudson.ExtensionFinder$GuiceFinder$FaultTolerantScope$1.get(ExtensionFinder.java:432)

I use Windows I will retry to reproduce again.

Hi slide_o_mix,

Here's how you can reproduce the issue with a clean Jenkins setup using Docker (cross-platform): 

docker run --name jenkins-test -p 30000:8080 --detach jenkins/jenkins:2.222.3-alpine

• Jenkins container starts in the background
• Check its logs for initial admin password (docker logs jenkins-test -f)
• Go to http://localhost:30000 and login with initial admin password
• Click on "Install suggested plugins" (this also installs the email-ext plugin 2.69)
• Create the admin user with any data, click "Save and Continue"
• Keep Jenkins URL as http://localhost:30000/,  click "Save and Finish" -> "Start Using Jenkins"
• Click on "Manage Jenkins" -> "Configure System"
• Type "// test" in the field "Default Pre-Send Script" and click "Save" <- this is what introduces the warning!

 
Now it's the tricky part, usually, after the first restart there's no warning

docker stop jenkins-test

• Wait for JVM to shut down and container to stop

docker start jenkins-test

• Check the logs, there's probably no errors this time, then you'll need to restart again

Shut down again:

docker stop jenkins-test

• Wait for JVM to shut down and container to stop

docker start jenkins-test

• Check the container logs, now there's a stack trace:
   

  2020-05-16 21:55:35.075+0000 [id=28] WARNING h.ExtensionFinder$GuiceFinder$FaultTolerantScope$1#error: Failed to instantiate Key[type=hudson.plugins.emailext.ExtendedEmailPublisherDescriptor, annotation=[none]]; skipping this component
  
  com.google.inject.ProvisionException: Unable to provision, see the following errors:
  
  1) Tried proxying hudson.plugins.emailext.ExtendedEmailPublisherDescriptor to support a circular dependency, but it is not an interface.
  
  1 error
  
  at com.google.inject.internal.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:52)
  at com.google.inject.internal.SingletonScope$1.get(SingletonScope.java:145)
  at hudson.ExtensionFinder$GuiceFinder$FaultTolerantScope$1.get(ExtensionFinder.java:440)
  

Just to clarify, this fails starting at 2.68?

Just to clarify, this fails starting at 2.68?

I doubt it, since we discovered this when upgrading from a rather old 1.x Jenkins installation. I'll try to figure out what the old version was exactly.

The old version was: 2.39.3. I'll try to find the version where it breaks ...

Looking into this now. I am able to reproduce it so I should be able to make some progress.

Will be in 2.72, see https://github.com/jenkinsci/email-ext-plugin/pull/210