record package metadata that describes co-installability

Specifically all entries in the Conflicts header are saved in the
conflict table, all entries in the Provides header are saved in the
provide table (to cover conflicts with virtual packages) and packages
using dpkg-divert in preinst get a magic "_dpkg-divert" entry in their
conflict table. With this metadata it should be possible to compute
undeclared file conflicts.

1 files changed, 23 insertions, 3 deletions

diff --git a/dedup/debpkg.py b/dedup/debpkg.py
index 2d67135..875a34d 100644
--- a/dedup/debpkg.py
+++ b/dedup/debpkg.py
@@ -2,6 +2,17 @@ from debian import deb822
 
 from dedup.hashing import hash_file
 
+def pkgname_from_dict(entry):
+    """Given an entry dictionary obtained from deb822, return the package
+    name.
+    @rtype: bytes
+    """
+    name = entry[u"name"]
+    # deb822 currently returns :any dependencies raw. see #670679
+    name = name.split(u':', 1)[0]
+    return name.encode("ascii")
+
+
 def process_control(control_contents):
     """Parses the contents of a control file from a control.tar.gz of a Debian
     package and returns a dictionary containing the fields relevant to dedup.
@@ -16,12 +27,21 @@ def process_control(control_contents):
         source = package
     version = control["version"].encode("ascii")
     architecture = control["architecture"].encode("ascii")
-    # deb822 currently returns :any dependencies raw. see #670679
-    depends = set(dep[0]["name"].split(u':', 1)[0].encode("ascii")
+    depends = set(pkgname_from_dict(dep[0])
                   for dep in control.relations.get("depends", ())
                   if len(dep) == 1)
+    conflicts = set(pkgname_from_dict(ent)
+                    for group in control.relations.get("conflicts", ())
+                    for ent in group)
+    conflicts.update(set(pkgname_from_dict(ent)
+                         for group in control.relations.get("replaces", ())
+                         for ent in group))
+    provides = set(pkgname_from_dict(ent)
+                   for group in control.relations.get("provides", ())
+                   for ent in group)
     return dict(package=package, source=source, version=version,
-                architecture=architecture, depends=depends)
+                architecture=architecture, depends=depends,
+                conflicts=conflicts, provides=provides)
 
 class MultiHash(object):
     def __init__(self, *hashes):