_emerge: depgraph: lookup unrecognized atoms in updates

[thesamesam]

This isn't suitable for merging right now, just posting so I can ask for some help.

Bug: https://bugs.gentoo.org/910572

[thesamesam]

@zmedico Do you have an idea for how to best do this? In particular, I don't want to penalise the success case (so "dev-build/make" having to incur a lookup).

Of course, could do the lookup in ambiguous_package_name, but that would only then help for a warning, not for fixing it up...

[zmedico]

Maybe we can do this expansion after _dep_expand, and possibly only do it after category expansion has failed?

[thesamesam]

OK, pushed a fixup (not squashed it). I tried a few things, including maybe treating this like the old PROVIDE case for virtuals, but this seemed to be the most elegant.

What do you reckon?

[zmedico]

Seems like _select_package would be better than _iter_match_pkgs_any.

[zmedico]

Maybe just use _iter_match_pkgs_any to translate the category/package-name, and let _select_package handle the rest.

[thesamesam]

OK, in 2a0f564 (#1234), it works, but I'm calling _add_pkg myself rather than relying on _select_package and then the _add_pkg later on in the function.

In 2cbc189 (#1234), I try to use the existing logic more, but that doesn't work.

[thesamesam]

_select_package ends up replacing it with an installed Package:

pkg=<Package ('binary', '/tmp/tmpruf_hub6/', 'dev-build/make-4.4', 'merge', 'None', '225', '0', '1705479700')>
   binary: dev-build/make-4.4::test_repo
installed: dev-build/make-4.4::test_repo
pkg=<Package ('installed', '/tmp/tmpruf_hub6/', 'dev-build/make-4.4', 'nomerge', 'installed')>

[zmedico]

So, _select_package operates on data from _set_args, so you need to call _set_args at some point with updated args. This loop isn't a good place to call _set_args, since it's supposed to be called before any packages are added to the graph (before _select_package is ever called), and called with all args at once rather than a single arg. Anyway, the tests pass with this diff:

--- a/lib/_emerge/depgraph.py
+++ b/lib/_emerge/depgraph.py
@@ -5321,8 +5321,12 @@ class depgraph:
 
                         if pkg:
                             atom = Atom(atom.replace(atom.cp, pkg.cp))
+                            arg.atom = dep.atom = atom
+                            arg.pset.replace([atom])
+                            self._set_args([arg])
 
-                            if not self._add_pkg(pkg, dep):
+                            # goto _select_package below
+                            if False:
                                 writemsg(
                                     f"\n\n!!! Problem resolving dependencies for {arg.arg=}, {arg.atom=}\n",

[zmedico]

For example, you might modify args inside _select_files in the for x in myfiles: loop that creates the args list, or just after that loop. Then your transformations will already be present when args is passed to _set_args.

[thesamesam]

Thanks Zac, I'm going to try get back to this tonight.