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Re: [setup topic/libsolv] Does "obsoletes:" work?


On 23/10/2017 18:43, Ken Brown wrote:
On 10/23/2017 7:38 AM, Jon Turney wrote:
On 21/10/2017 21:18, Ken Brown wrote:
On 10/20/2017 6:24 PM, Ken Brown wrote:
Have you ever tested the "obsoletes:" feature of setup/libsolv?  I tried adding an "obsoletes:" line to setup.ini, and it didn't seem to have any effect.

It seems I tested it back in May, so it might well have broken since :)

Here's a very small test repo I've been using for some tests:
http://www.dronecode.org.uk/cygwin/test/x86_64/

But yes, your patch looks like it's needed for it to work correctly...

It turns out that it *is* working (after a minor fix, attached), but not always as I expect.  Suppose A requires B and C obsoletes B. Then the "obsoletes" statement appears to have no effect.  If I remove the dependence of A on B, then setup does propose uninstalling B and installing C.

I guess the issue is that libsolv interprets "C obsoletes B" as "uninstall B and install C", and it won't uninstall B while something requires it.

The 'targeted' vs. 'untargeted' distinction is relevant here? Perhaps we are doing the wrong one?

Maybe.  I've read and re-read the discussion of this in libsolv-bindings.txt, and I'm still not sure I understand it.

Yeah, the documentation is a bit impenetrable.

But here's a simpler case where "obsoletes" isn't working as I expect. Using your test repo, in which A requires C and obsoletes B, I start with none of the packages installed.  I choose B for installation (either interactively or on the command line), and B gets installed.  If I now run setup a second time, A and C get installed and B gets uninstalled.

I expected A and C to be installed on the first run.  I don't think this has anything to do with targeted vs. untargeted, because that distinction is only relevant for updating installed packages.

I guess I had the opposite expectation (if I ask for A to be installed, that's what should happen, because if it insists on upgrading it behind my back there's no way to do that...)

The actual behaviour you mention fits what's described there pretty well.


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