How do I modify a Jenkins plugin to stop it from putting a link on build pages?

Question

I'm trying to modify the existing EnvInject plugin so that the Environment Variables link it puts on a build's page is hidden. If I'm understanding the Jenkins API correctly, I should be able to do this by finding where the Action interface is implemented and having getIconFileName() return null.

I found that method implemented in EnvInjectAction.java and modified it to return null, but this had no effect--the link is still visible on build pages. I even tried modifying getDisplayName() and getUrlName() to also return null, but this also had no effect. Here is the modified method:

public String getIconFileName() {
        return null;
}

I've taken care to follow the instructions for deploying a custom build of a core plugin from the Jenkins plugin tutorial, and I've also tried rebooting the machine that Jenkins is running on, all to no avail.

I'm clearly missing something vital, but I can't figure out what it could be. What else do I need to do to make the plugin not display the Environment Variables link?

Answer 1

Why do you want to do that? To hide sensitive information?

Are you aware of that even if you remove the link the variables can be displayed via:
http://jenkins/job/YourJob/1/injectedEnvVars?

Or according to the EnvInjectPlugin-VariablesTraceability:

"You can also get build environment variables by the following
HTTP GET URL: <jenkins_url>/job/<job_name>/<build_number>/injectedEnvVars/export"

However, if it's just to remove the link and modifying the plugin is not a must add the following to Jenkins' run/jenkins/war/css/style.css:

a[href*='/injectedEnvVars'] {
  display: none;
}

Make a backup copy of the adapted style.css since it might get overwritten with a:

$ sudo service jenkins --full-restart

UPDATE

You can use a custom CSS with the following:

Manage Jenkins → Configure System → Theme → URL of theme CSS: ...