I've come up with a work around that suits my needs, maybe it is of interest.

https://wiki.freebsd.org/2021FoundationCFI search for "freebsd-update improvements", I did ask for help - hopefully someone can take up where I left off.

I'm no longer spending my time on D32570.

Please elaborate on "This will still break"? That lacks a reasonable explanation.

only expedite if BASEDIR is /

don't need to induce old fashioned fetch after install

Sorry, another thought: What happens in the following sequence of events?

1. `freebsd-update fetch`
2. `freebsd-update install`
3. `freebsd-update fetch`
4. `freebsd-update rollback`
5. `freebsd-update fetch`

added PAGER for outputting fetch_create_manifest.out

reverted the changes in upgrade_run

Colin suggested splitting the manifest function in two but I'm not seeing how to do that, I'm sure it's possible but at this stage that has me stumped.

Regarding #2, This use case was something I tested with along the way (this VM was deliberately out of date for this). It looks like this:

root@pull543:~ # freebsd-update fetch install
src component not installed, skipped
Looking up update.FreeBSD.org mirrors... 2 mirrors found.
Fetching metadata signature for 13.0-RELEASE from update2.freebsd.org... done.
No updates are available to fetch.
Creating snapshot of existing boot environment... done.
Installing updates...

In D32570#735374, @cperciva wrote:

Needs an update to freebsd-update.8 since -F is being repurposed.

Take out the bit about "Force", simply focus on tag/tag.new and fetch_run prior completion.

Put in what I hope is a better commented explanation.

Some more explanation in the comments.

Some more explanation in the comments.

introduces a way to test that fetch_run ran to completion in a way that allows the new tag match test

In D32570#735375, @cperciva wrote:

This will break very badly if freebsd-update fetch gets interrupted. The file tag is created at the end of fetch_metadata so the fact that it exists does not imply that the fetch completed.

@imp a new squashed commit pushed to github (should be the same as now)

Style change for @imp and @emaste (re-upload, diff against the right commit ID this time...)

Change to suit style for @imp and @emaste.

In D32570#735374, @cperciva wrote:

Needs an update to freebsd-update.8 since -F is being repurposed.