Add a check for clobbered packages in overlays

Add a check that reports if a given package clobbers a package from
the master repository.  Since this only applies to some repositores
(e.g. ::guru), it is optional (disabled by default).

Closes: #745
Signed-off-by: Michał Górny <[email protected]>

Author: mgorny

src/pkgcheck/checks/overlays.py

@@ -2,7 +2,7 @@
 from snakeoil.strings import pluralism
 
 from .. import results, sources
-from . import MirrorsCheck, OptionalCheck, OverlayRepoCheck, RepoCheck
+from . import Check, MirrorsCheck, OptionalCheck, OverlayRepoCheck, RepoCheck
 
 
 class UnusedInMastersLicenses(results.VersionResult, results.Warning):
@@ -132,3 +132,34 @@ def feed(self, pkg):
             non_local_use = pkg.iuse_stripped.difference(pkg.local_use.keys())
             if flags := self.unused_master_flags.intersection(non_local_use):
                 yield UnusedInMastersGlobalUse(sorted(flags), pkg=pkg)
+
+
+class MasterPackageClobbered(results.PackageResult, results.Error):
+    """Package in master is clobbered by package in overlay.
+
+    A repository (such as ``::guru``) that is supposed to only provide
+    additional packages to its masters (``::gentoo``), provides a package
+    that is found in its master, therefore potentially clobbering it.
+    """
+
+    def __init__(self, repository: str, **kwarg):
+        super().__init__(**kwarg)
+        self.repository = repository
+
+    @property
+    def desc(self):
+        return f"package from repository ::{self.repository} clobbered"
+
+
+class MasterPackageClobberedCheck(OverlayRepoCheck, OptionalCheck):
+    """Detect clobbering packages from master."""
+
+    _source = sources.PackageRepoSource
+    known_results = frozenset([MasterPackageClobbered])
+
+    def feed(self, pkgset):
+        for pkg in pkgset:
+            for repo in self.options.target_repo.masters:
+                if repo.has_match(pkg.unversioned_atom):
+                    yield MasterPackageClobbered(str(repo), pkg=pkg)
+            break

testdata/data/repos/overlay/MasterPackageClobberedCheck/MasterPackageClobbered/expected.json

@@ -0,0 +1 @@
+{"__class__": "MasterPackageClobbered", "category": "MasterPackageClobberedCheck", "package": "MasterPackageClobbered", "repository": "overlayed"}

testdata/repos/overlay/MasterPackageClobberedCheck/MasterPackageClobbered/MasterPackageClobbered-0.ebuild

@@ -0,0 +1,4 @@
+DESCRIPTION="Ebuild clobbered by overlay"
+HOMEPAGE="https://github.com/pkgcore/pkgcheck"
+LICENSE="BSD"
+SLOT="0"

testdata/repos/overlay/profiles/categories

@@ -1,2 +1,3 @@
+MasterPackageClobberedCheck
 UnusedInMastersCheck
 VisibilityCheck

testdata/repos/overlayed/MasterPackageClobberedCheck/MasterPackageClobbered/MasterPackageClobbered-0.ebuild

@@ -0,0 +1,4 @@
+DESCRIPTION="Ebuild clobbered by overlay"
+HOMEPAGE="https://github.com/pkgcore/pkgcheck"
+LICENSE="BSD"
+SLOT="0"

testdata/repos/overlayed/profiles/categories

@@ -1 +1,2 @@
+MasterPackageClobberedCheck
 stub