apt/test/integration/test-multiarch-foreign, branch main

solver3: Rename decision to assignment

2026-01-05T21:20:24Z

The previous use of decision here conflicted with the use of decision level and the general notion of having made a decision, because the assignment might have been propagated as a matter of fact.

solver3: Verbose error messages

2025-03-08T22:18:05Z

Introduce a new function, LongWhyStr() that returns a longer reason for why something is being installed (or not). This does the same path walk as the other function does, but it renders the clauses at each level, and one per line, so the whole output is a lot more informative. It is a separate function to keep the existing debug messages use the simple single line implication graph We remove the other special case in AddWork() for empty solutions to mke use of the general case in Solve() instead, and then adapt the case in Solve() to the same case as in Enqueue(). This also happens to fix the bug that when we encountered an empty clause we just printed the clause had no solution, but not how we got to install the package with the clause. Adapt the test suite for the changes which is an annoying amount of paperwork.

solver3: Only enqueue shared dependencies at the package level

2025-02-14T18:08:45Z

Dependencies shared by all versions are enqueued at the package level, so avoid enqueuing duplicates at the version level. This presumably has no meaningful impact on performance, potentially a negative performance impact on some workloads as we now need to find the duplicates again; it can become useful when there is a lot of backtracking. More importantly though this improves error messages, because now we can say that "all versions of foo depend on X", rather than saying "foo=1 depends on X" and you are left wondering why we did not select "foo=2". In this commit though, improved error messages are not implemented, they depend on redesigning the reason tracking to use clauses. Also the rationale tracking includes a lot more dependencies of the form "pkg:arch=version -> pkg:arch" which are annoying. Improved error messages should fold them into one node.

solver3: Use a propagation queue

2025-01-30T13:50:15Z

Instead of directly propagating in a recursive fashion, queue propagations in a queue and work on them in a loop per the miniSAT paper. We call Propagate() only at the end of the FromDepCache() function and then in the Solve loop. Delaying the initial propagation means that we get a stronger reasoning: Assume you have x->a->b->c, y->c and you install x,y: - Previously we traversed: x, y, x->a, a->b, b->c, (y->c) - but now we traverse: x, y, x->a, y->c, a->b, (b->c) Notably c now has the implication y->c instead of x->a->b->c. Inside the solver we need to call Propagate in a loop: Propagating facts can fail and we then backtrack. If backtracking is succesful, we have gained a new fact to propagate.

test: Support the 3.0 solver in most existing test cases

2024-05-24T15:01:35Z

Highlights: - test-bug-618848-always-respect-user-requests: (Do not) Support 3.0 solver A manually installed package is never removed just because we request the removal of its dependency in solver3. - test-bug-657695-resolver-breaks-on-virtuals: Support 3.0 solver For manually installed packages, solver 3.0 would require some new xserver-xorg-video-driver to Conflict+Replace+Provides the old one (once the logic is implemented), but that does seem reasonable. - test-bug-720597-build-dep-purge: Support 3.0 solver This needs a simple aptmark auto because pkga is removed by the build-dep. But further adjustments are necessary because it weirdly tested for no autoremovable packages before installing pkgc. - test-bug-960705-*: Support 3.0 solver Bit awkward to deal with; notably the protect to conflict doesn't actually work anymore and that is a feature these days.

fix M-A:foreign provides creation for unknown archs

2016-01-14T22:08:02Z

Architectures for packages which do not belong to the native nor a foreign architecture (dubbed barbarian for now) which are marked M-A:foreign still provide in their own architecture even if not for others. Also, other M-A:foreign (and allowed) packages provide in these barbarian architectures.

tests: support spaces in path and TMPDIR

2015-12-19T22:04:34Z

This doesn't allow all tests to run cleanly, but it at least allows to write tests which could run successfully in such environments. Git-Dch: Ignore

tests: use quiet level 0 by default in tests

2015-11-19T16:13:56Z

Git-Dch: Ignore

implement dpkgs vision of interpreting pkg: dependencies

2015-09-14T13:22:18Z

How the Multi-Arch field and pkg: dependencies interact was discussed at DebConf15 in the "MultiArch BoF". dpkg and apt (among other tools like dose) had a different interpretation in certain scenarios which we resolved by agreeing on dpkg view – and this commit realizes this agreement in code. As was the case so far libapt sticks to the idea of trying to hide MultiArch as much as possible from individual frontends and instead translates it to good old SingleArch. There are certainly situations which can be improved in frontends if they know that MultiArch is upon them, but these are improvements – not necessary changes needed to unbreak a frontend. The implementation idea is simple: If we parse a dependency on foo:amd64 the dependency is formed on a package 'foo:amd64' of arch 'any'. This package is provided by package 'foo' of arch 'amd64', but not by 'foo' of arch 'i386'. Both of those foo packages provide each other through (assuming foo is M-A:foreign) to allow a dependency on 'foo' to be satisfied by either foo of amd64 or i386. Packages can also declare to provide 'foo:amd64' which is translated to providing 'foo:amd64:any' as well. This indirection over provides was chosen as the alternative would be to teach dependency resolvers how to deal with architecture specific dependencies – which violates the design idea of avoiding resolver changes, especially as architecture-specific dependencies are a cornercase with quite a few subtil rules. Handling it all over versioned provides as we already did for M-A in general seems much simpler as it just works for them. This switch to :any has actually a "surprising" benefit as well: Even frontends showing a package name via .Name() [which doesn't show the architecture] will display the "architecture" for dependencies in which it was explicitely requested, while we will not show the 'strange' :any arch in FullName(true) [= pretty-print] either. Before you had to specialcase these and by default you wouldn't get these details shown. The only identifiable disadvantage is that this complicates error reporting and handling. apt-get's ShowBroken has existing problems with virtual packages [it just shows the name without any reason], so that has to be worked on eventually. The other case is that detecting if a package is completely unknown or if it was at least referenced somewhere needs to acount for this "split" – not that it makes a practical difference which error is shown… but its one of the improvements possible.

M-A: allowed pkgs of unconfigured archs do not statisfy :any

2015-09-14T13:22:18Z

We parse all architectures we encounter recently, which means we also parse packages from architectures which are neither native nor foreign, but still came onto the system somehow (usually via heavy force).