[ANN] Credentials Plugin 2.2.0 to require Jenkins 2.60.1+

[Stephen Connolly]

From http://stats.jenkins.io/pluginversions/credentials.html 

28% of people have upgraded credentials to 2.1.16

91% of installations of credentials 2.1.16 are using Jenkins 2.60.1 or newer

It is 2 months since the 2.1.16 release of the credentials plugin. The 72% of people who have not upgraded to credentials 2.1.16 are more than likely not feeling the need to upgrade, the plugin works well enough for them. Consequently, I shall exclude them from my decision on what the baseline Jenkins requirements are for the next release of the plugin... just because I release a newer version, does not mean they need to upgrade... as evidenced by their not upgrading ;-)

My (previously undocumented) 90% threshold has been passed with Jenkins 2.60.1, consequently the Credentials plugin is moving its baseline to 2.60.1

This is not a debate, as maintainer of the plugin I have made the decision. If somebody wants to maintain a 2.1.x line and take the work of back-porting any fixes, I will consider supporting them in that task, but the time I have will be focused on the 2.2.x line.

Some of the improvements to the credentials API that I want to make require features of Java 8, hence given that the 90% threshold has been passed, I am pulling the trigger.

The reason I am sending this announcement is to alert all downstream plugin developers.

If (after I cut a 2.2.x release) you update your dependency on Credentials API to 2.2.0 or newer, you will also be moving your Jenkins baseline to 2.60.1+ and your Java baseline version to 8. Please assess the impact to your users. 

An example,

  git, the version that is at least two months old is 3.5.1, the 90% installation cut-off for git is Jenkins 2.46.1 thus according to my completely made up decision point (plugin release must be available for at least 2 months, 90% of users with the plugin installed must be using that Jenkins version or newer) I would not update the git plugin past Jenkins 2.46.1 just yet... however the month and a half 3.6.0 does currently have 92% of users with Jenkins 2.60.1, so using my measure and assuming that the december stats follow trend, I would think the git plugin could bump Jenkins baseline in December... and consequently bump Credentials API version too...

NOTE: I only co-maintain the git plugin and Mark is probably the decider on the policy to follow with the git plugin.

I recommend that every plugin developer define their compatibility policy on their wiki page. I have added my policy for the credentials plugin to its wiki page:

At least 90% of installations using the most recent version of the plugin that is at least 2 months old shall be able to upgrade to the latest version of the plugin.

As a plugin maintainer, the policy you pick is entirely your choice, but I strongly recommend picking a policy and documenting it as I have done (and I will be applying the same/similar policy to the other plugins I maintain)

P.S. it may be some time before I cut a 2.2.0 release of credentials... or it could be quite soon... I have made the decision and I think it fair to provide warning as early as possible

-Stephen