Merge branch 'master' into buildbot-0.8.0

* master:
  add a default value for scheduler state 'last_processed' - fixes buildbot#816

buildbot/changes/manager.py

@@ -127,3 +127,5 @@ def getChangesGreaterThan(self, last_changeid, t=None):
         return self.parent.db.getChangesGreaterThan(last_changeid, t)
     def getChangesByNumber(self, changeids):
         return self.parent.db.getChangesByNumber(changeids)
+    def getLatestChangeNumberNow(self, t=None):
+        return self.parent.db.getLatestChangeNumberNow(t)

buildbot/db/connector.py

@@ -369,6 +369,19 @@ def changeEventGenerator(self, branches=[], categories=[], committers=[], minTim
         for (changeid,) in rows:
             yield self.getChangeNumberedNow(changeid)
 
+    def getLatestChangeNumberNow(self, t=None):
+        if t:
+            return self._txn_getLatestChangeNumber(t)
+        else:
+            return self.runInteractionNow(self._txn_getLatestChangeNumber)
+    def _txn_getLatestChangeNumber(self, t):
+        q = self.quoteq("SELECT max(changeid) from changes")
+        t.execute(q)
+        row = t.fetchone()
+        if not row:
+            return 0
+        return row[0]
+
     def getChangeNumberedNow(self, changeid, t=None):
         # this is a synchronous/blocking version of getChangeByNumber
         assert changeid >= 0

buildbot/schedulers/base.py

@@ -131,7 +131,12 @@ def classify_changes(self, t):
         db = self.parent.db
         cm = self.parent.change_svc
         state = self.get_state(t)
-        last_processed = state["last_processed"]
+        state_changed = False
+        last_processed = state.get("last_processed", None)
+
+        if last_processed is None:
+            last_processed = state['last_processed'] = cm.getLatestChangeNumberNow(t)
+            state_changed = True
 
         changes = cm.getChangesGreaterThan(last_processed, t)
         for c in changes:
@@ -146,4 +151,7 @@ def classify_changes(self, t):
         if changes:
             max_changeid = max([c.number for c in changes])
             state["last_processed"] = max_changeid # retain other keys
+            state_changed = True
+
+        if state_changed:
             self.set_state(t, state)