Link to update-excuse bugs on update_excuses

LP: #1683749

britney.py

@@ -65,6 +65,9 @@ Other than source and binary packages, Britney loads the following data:
   * Blocks, which contains user-supplied blocks read from Launchpad bugs
     (see LPBlockBugPolicy).
 
+  * ExcuseBugs, which contains user-supplied update-excuse read from
+    Launchpad bugs (see LPExcuseBugsPolicy).
+
 For a more detailed explanation about the format of these files, please read
 the documentation of the related methods. The exact meaning of them will be
 instead explained in the chapter "Excuses Generation".
@@ -202,7 +205,7 @@ from britney2.hints import HintParser
 from britney2.installability.builder import build_installability_tester, ma_parse_depends
 from britney2.migrationitem import MigrationItem
 from britney2.policies.policy import AgePolicy, RCBugPolicy, PiupartsPolicy, PolicyVerdict
-from britney2.policies.policy import LPBlockBugPolicy
+from britney2.policies.policy import LPBlockBugPolicy, LPExcuseBugsPolicy
 from britney2.policies.autopkgtest import AutopkgtestPolicy
 from britney2.policies.sourceppa import SourcePPAPolicy
 from britney2.policies.sruadtregression import SRUADTRegressionPolicy
@@ -536,6 +539,7 @@ class Britney(object):
         # Piuparts is noisy & not used by Ubuntu (LP: #1651537)
         # self.policies.append(PiupartsPolicy(self.options, self.suite_info))
         self.policies.append(LPBlockBugPolicy(self.options, self.suite_info))
+        self.policies.append(LPExcuseBugsPolicy(self.options, self.suite_info))
         if getattr(self.options, 'adt_enable') == 'yes':
             self.policies.append(AutopkgtestPolicy(self.options, self.suite_info))
         self.policies.append(SourcePPAPolicy(self.options, self.suite_info))

britney2/policies/policy.py

@@ -698,3 +698,48 @@ class LPBlockBugPolicy(BasePolicy):
         excuse.addreason('block')
 
         return PolicyVerdict.REJECTED_PERMANENTLY
+
+class LPExcuseBugsPolicy(BasePolicy):
+    """update-excuse Launchpad bug policy to link to a bug report, does not prevent migration
+
+    This policy will read an user-supplied "ExcuseBugs" file from the unstable
+    directory (provided by an external script) with rows of the following
+    format:
+
+        <source-name> <bug> <date>
+
+    The dates are expressed as the number of seconds from the Unix epoch
+    (1970-01-01 00:00:00 UTC).
+    """
+    def __init__(self, options, suite_info):
+        super().__init__('update-excuse', options, suite_info, {'unstable'})
+
+    def initialise(self, britney):
+        super().initialise(britney)
+        self.excuse_bugs = {}  # srcpkg -> [(bug, date), ...]
+
+        filename = os.path.join(self.options.unstable, "ExcuseBugs")
+        self.log("Loading user-supplied excuse bug data from %s" % filename)
+        for line in open(filename):
+            l = line.split()
+            if len(l) != 3:
+                self.log("ExcuseBugs, ignoring malformed line %s" % line, type='W')
+                continue
+            try:
+                self.excuse_bugs.setdefault(l[0], [])
+                self.excuse_bugs[l[0]].append((l[1], int(l[2])))
+            except ValueError:
+                self.log("ExcuseBugs, unable to parse \"%s\"" % line, type='E')
+
+    def apply_policy_impl(self, excuse_bugs_info, suite, source_name, source_data_tdist, source_data_srcdist, excuse):
+        try:
+            excuse_bug = self.excuse_bugs[source_name]
+        except KeyError:
+            return PolicyVerdict.PASS
+
+        for bug, date in excuse_bug:
+            excuse_bugs_info[bug] = date
+            excuse.addhtml("Also see <a href=\"https://launchpad.net/bugs/%s\">bug %s</a> last updated on %s" %
+                           (bug, bug, time.asctime(time.gmtime(date))))
+
+        return PolicyVerdict.PASS