factor out dsc comparison into a method on ubuntutools.archive.Dsc

syncpackage

@@ -349,28 +349,10 @@ def copy(src_pkg, release, simulate=False, force=False):
         # Check whether a fakesync would be required.
         src_pkg.pull_dsc(quiet=not Logger.verbose)
         ubuntu_pkg.pull_dsc(quiet=not Logger.verbose)
-        for field, key in (('Checksums-Sha256', 'sha256'),
+        if not src_pkg.dsc.compare_dsc(ubuntu_pkg.dsc):
-                           ('Checksums-Sha1', 'sha1'),
+            Logger.error('The checksums of the Debian and Ubuntu packages '
-                           ('Files', 'md5sum')):
+                         'mismatch. A fake sync using --no-lp is required.')
-            if field not in src_pkg.dsc or field not in ubuntu_pkg.dsc:
+            sys.exit(1)
-                continue
-            debian_checksums = \
-                dict((entry['name'], (int(entry['size']), entry[key]))
-                     for entry in src_pkg.dsc[field])
-            ubuntu_checksums = \
-                dict((entry['name'], (int(entry['size']), entry[key]))
-                     for entry in ubuntu_pkg.dsc[field])
-            for name, (size, checksum) in debian_checksums.iteritems():
-                if name not in ubuntu_checksums:
-                    # new file
-                    continue
-                if (size != ubuntu_checksums[name][0] or
-                    checksum != ubuntu_checksums[name][1]):
-                    Logger.error('The checksums of the Debian and Ubuntu '
-                                 'packages mismatch. A fake sync using '
-                                 '--no-lp is required.')
-                    sys.exit(1)
-            break # one checksum is good enough
     except udtexceptions.PackageNotFoundException:
         Logger.normal('Source %s -> %s/%s: not in Ubuntu, new version %s',
                       src_pkg.source, ubuntu_series, ubuntu_pocket,

ubuntutools/archive.py

@@ -95,6 +95,30 @@ class Dsc(debian.deb822.Dsc):
             return hash_func.hexdigest() == digest
         return False
 
+    def compare_dsc(self, other):
+        """Check whether any files in these two dscs that have the same name
+        also have the same checksum."""
+        for field, key in (('Checksums-Sha256', 'sha256'),
+                           ('Checksums-Sha1', 'sha1'),
+                           ('Files', 'md5sum')):
+            if field not in self or field not in other:
+                continue
+            our_checksums = \
+                dict((entry['name'], (int(entry['size']), entry[key]))
+                     for entry in self[field])
+            their_checksums = \
+                dict((entry['name'], (int(entry['size']), entry[key]))
+                     for entry in other[field])
+            for name, (size, checksum) in our_checksums.iteritems():
+                if name not in their_checksums:
+                    # file only in one dsc
+                    continue
+                if (size != their_checksums[name][0] or
+                    checksum != their_checksums[name][1]):
+                    return False
+            return True # one checksum is good enough
+        return True
+
 
 class SourcePackage(object):
     """Base class for source package downloading.