pmb.parse.depends: ignore conflict dependency that no longer exists (MR 2181)

So it looks like some packages might be mentioned in the "depends=" of
other packages and marked as conflict, for example:
    depends="!foo"

..and the conflicting package can be dropped from the repo entirely if
it is no longer needed, however the reference to it in `depends=` still
exists. This handles that situation by just ignoring the missing package
if it is only a conflicting dependency.

fixes https://gitlab.com/postmarketOS/pmaports/-/issues/1525

pmb/parse/depends.py

@@ -144,6 +144,11 @@ def recurse(args, pkgnames, suffix="native"):
 
         # Nothing found
         if not package:
+            if is_conflict:
+                # This package was probably dropped from the repos, so we don't
+                # care if it doesn't exist since it's a conflicting depend that
+                # wouldn't be installed anyways.
+                continue
             source = 'world'
             if pkgname_depend in required_by:
                 source = ', '.join(required_by[pkgname_depend])

test/test_parse_depends.py

@@ -146,13 +146,16 @@ def test_recurse(args, monkeypatch):
     depends = {
         "test": ["libtest", "so:libtest.so.1"],
         "libtest": ["libtest_depend"],
-        "libtest_depend": ["!libtest_conflict"],
+        "libtest_depend": ["!libtest_conflict", "!libtest_conflict_missing"],
         "libtest_conflict": [],
         "so:libtest.so.1": ["libtest_depend"],
     }
 
     def package_from_index(args, pkgname, install, aport, suffix):
-        return {"pkgname": pkgname, "depends": depends[pkgname]}
+        if pkgname in depends:
+            return {"pkgname": pkgname, "depends": depends[pkgname]}
+        else:
+            return None
     monkeypatch.setattr(pmb.parse.depends, "package_from_index",
                         package_from_index)