Clicking twice on a plug-in update deletes the plug-in.

[lmarks]

I check to see if there are updates to the plugins every day or two. After I clicked Update, I clicked it again, not quite fast enough to register as a double-click. (I am 78 years old, and even though I don't want to admit it, I should blame this on a tremor.) It appears that two processes started running against the one plugin.

What apparently happened is that the first process started to run by deleting the old plug-in. The second process saw that the plug-in wasn't there and stopped and seemed to have stopped the first. In any case, there was no trace that the plugin had ever been installed.

To reproduce
Pick some plug-in that needs an update.
Click to install the update.
Click again to install the update. (Timing might be critical here, not sure.)

Proposed Fix
Add a semaphore which disables starting an update on a plugin after one has started.

Why this is important <WHINE>
Our organization is the state chapter of a national organization.
The national organization coordinator doesn't know much about web development.
He paid a developer to develop 55 similar websites for 50 states and 5 territories.
He hired a consultant to arrange hosting. The consultant recommended a hosting company, not WordPress.com.

Every time I attempt to make an update, I receive a prompt to take a Backup first. If I accept that it fails. I do not have authority to take backups. When I questioned this, years ago, the hosting company said, "Don't worry. We take daily backups." When I called the hosting company this time, to restore the backup, they said (see if you can guess...) "You don't have the authority to request a restoration."

So I called the national coordinator who called the consultant who called the hosting company to request a restoration. By the time this got to the bottom of the chain, at least one more automatic daily backup was taken--and that one was restored. So far I have been unable to get it through their heads that the backup to be restored must be from BEFORE the incident.

The plugin that happens to have been deleted happens to be the one that handles forms:
The forms to contact any of our officers or committee chairs, People seeking that get a blank page.
The forms to pay dues--and the Second Notice was sent out just a few days before this event. Members seeking that get a blank page.
And about eight other functions get a blank page.
[Later...]
The website has been restored to status of a week ago. I am trying to remember all the changes I had made.

Are there any formal guidelines regarding withholding permissions for backup and restore that I can show to the national coordinator?

Sorry, just had to get this off my chest.
<WHINE>

[SergeyBiryukov]

Hi there, welcome back to WordPress Trac! Thanks for the ticket.

This appears to be a part of a larger issue described in #53705.

Adjusting the keywords as per ​Trac Workflow Keywords.