Enabled when all attempts to satisfy a name failed, we know that we
can ignore all decisions until we find a decision affecting the name
we wanted to satisfy.
We can't just use the primary name, as that would mess up
backtracking. We need to record the name which caused the name
to get considered - that way the right last_touched_decision is
used on backtracking.
* push_decision expects to always get the package primary 'name'
as apk_name. ASSERT that and fix problem cases.
(though - this might need to be reverted, and store the non
primary name in apk_decision instead to accomodate for better
backtracking optimizations)
* fix error reporting of virtual package names
* make 'assign_name' errors soft. the incorrect packages just are
no longer consider instead of aborting whole calculation.
* fix backtracking of virtual packages that are not depended
directly
apk_name_state is now quite small; and we avoid overhead of two
pointers (+ malloc overhead) when we just make it part of apk_name.
It also fixes some problems (that got introduced) where apk_name_state
was not allocated.
Solver will now never report partial solution where a conflict
constraint is not satisfied. The is because with --force we might
install the partial solution; and if conflicted packages were to
be installed we might have extra trouble.
Required for provides support as package might be pulled in via
non-primary package name. This allows relatively easily to pass
through inherited flags via the provided names. ref #574.
Reasoning:
- it is less useful now that we do not do common dependency merging
- provides support would make the required logic overly complicated
- callgrind reports that depending on the case it can improve or
decrease performance (the overhead pays off only in some cases);
the difference is not large either way
Otherwise we might start to change packages unexpectedly when not
upgrading. This also fixes some other things the solver might've
decided to do.
Add also few test cases to detect bad behaviour.
In case someone did "fix --force" for package for which we have no
APK available, we would uninstall the package instead of silently
ignoring the request. This could mean worse things.
So now we just consider unavailable packages a bad deal for reinstall
requests. And will downgrade if necessary. But if we really don't
have any APK available, we just skip the request but report it.
If n+1 packages depend A, and A depend on B. Add n+1 dependencies
to B. Otherwise if someone conflicts B, B might be left out.
Leaving package unassigned is no longer a non-preferred action,
this fixes the final test case that was failing.
And with --force we might even install that scenario.
Add also some debug checks.
callgrind says it's more overhead than improvement. back jumping
effectively prunes all bad trees. but can be added later if it
becomes needed; due to e.g. provides support.
It is faster to just scan the cache directory for existing packages
at startup than trying to faccessat() them on demand. It also makes
quite a few parts of the code more readable and simpler.
* properly do absolute scoring now, the previous scoring where
preference could get reduced could have caused incorrect early
pruning of search tree
* backtracking is now separated from package state, and first
branching point is the decision if a name is left unassigned
or if something _has_ to be assigned. this allows multiple future
search tree optimizations like handling of common dependencies
early.
* merge common dependency names early to provide deeper forward
checking.
Timo Teräs