Created attachment 696461 [details]
Warning only displayed on the upgrade summary

Although the upgrade warns about insufficient space available on the summary
page, if the user clicks "Update", there is no more warnings specific to that
issue, just two license notices and a general "ready to install" page.

If the upgrade is actually attempted, the upgrade fails (predictably) with
"insufficient space" errors and aborting the installation at this point results
in a broken system.  Is this intended behaviour or not?