[PATCH] Revert "Don't override a Keep selection"

[Ken Brown]

On 10/18/2017 11:01 PM, Ken Brown wrote:
> On 10/17/2017 3:31 PM, Ken Brown wrote:
>> On 10/17/2017 2:43 PM, Jon Turney wrote:
>>> On 16/10/2017 20:13, Ken Brown wrote:
>>>> This reverts (the rest of) commit b43b697.  Part of that commit was
>>>> already reverted in commit ff0bb3d.  The rest is not needed either
>>>> since we no longer send the upgrade flag to the solver after the user
>>>> has made their selections.
>>>> ---
>>>>   libsolv.cc     | 14 +++-----------
>>>>   libsolv.h      |  1 -
>>>> Â  package_meta.h |Â  2 --
>>>> Â  3 files changed, 3 insertions(+), 14 deletions(-)
>>>
>>> Hmm... not sure about this.
>>>
>>> Say the initial upgrade solution had something like: package A 1.0 -> 
>>> 1.1, and A 1.1 has a dependency on package B 2.0, where currently B 
>>> 1.0 is installed (so B 1.0 -> 2.0)
>>>
>>> If the user then changes B to 'keep' (at 1.0), we should report a 
>>> conflict?
>>
>> Good point.  I wasn't thinking about dependencies with version relations.
> 
> I just tested this scenario, and it turns out that putting a lock on B 
> 1.0 overrides the dependency of A 1.1 on B 2.0.  There's no problem 
> reported.  On the other hand, if there's no lock, then the dependency 
> overrides the Keep choice, again with no problem reported.
> 
> Back to the drawing board.

Thinking about this further, using SOLVER_LOCK is probably the right 
thing to do in this situation, even if no problem is reported.  We can't 
insist that users install the recommended version.  For example, if I 
choose to downgrade binutils while keeping the current gcc, then I'm 
responsible for any breakage this might cause, with or without a warning 
from setup.

I'll prepare a new patch that restores the SOLVER_LOCK functionality 
that was inadvertently removed in commit ff0bb3d.

Ken