Re: Bug#504880: Disambiguate "installed" for packages

[Jonathan Nieder <jrnieder@gmail.com>]

Russ Allbery wrote:

> Suppose that you have a package foo 1.0-1 with:
> 
>     Pre-Depends: bar
> 
> and a package foo 2.0-1 that has no pre-dependencies.
[...]
> Now you run:
> 
>     dpkg -i foo_2.0-1.deb
> 
> foo 2.0-1 has no pre-dependencies, so the pre-dependency check succeeds.
> Installation proceeds and foo 2.0-1 is unpacked, and then the foo 1.0-1
> postrm upgrade fails.  Error unwind happens and the foo 1.0-1 preinst is
> called with abort-upgrade.  bar is only half-installed.

Ah, the “you can’t depend on future maintainers” rule again.

|	                                  Pre-dependencies will be
|	at least unpacked following the same rules as above, except
|	they may be only "Half-Installed" if an upgrade of the
|	pre-dependency failed.

Maybe a footnote would be appropriate - something like

	[1] This can happen if the new package no longer pre-depends
	on a package that has been partially upgraded.

Thanks for the explanation.
Jonathan