Clicking "Check Again" within 1 minute of a previous check does nothing

[dd32]

On the Updates page, clicking "Check Again" within 1 minute of the last core update check doesn't actually do anything.. This is because the cache lasts for at least 1 minute.

This is particularly annoying for development users who change the version string as it leads to a frustrating minute.

One other potential way to approach this is that $wp_version should invalidate the existing transient somehow.

[dd32]

25831.diff​ tackles it from both angles

• Adds a parameter to force-check for new updates, it relies on the fact that extra stats bypass the update-check limiter.
• Adds $wp_version invalidation.

I'm not certain that the force-check should be added, although it does make the button do what it says.
The $wp_version invalidation seems appropriate.

[dd32]

In 26188:

Invalidate the 'update_core' Update check transient when $wp_version changes. See #25831

[dd32]

In 26192:

Updates: Force an update check to occur when the 'Check Again' button is used in the Dashboard. Fixes #25831