fix bug in PostHookBreakpoint, add test

vtrace/breakpoints.py

@@ -389,6 +389,10 @@ class PostHookBreakpoint(NiceBreakpoint):
                 print('Post hook callback "%s" exception: %s' % (hook_cb, str(e)))
 
     def notify(self, event, trace):
-        ret_addr, args = self.parent.callinfo[trace.getCurrentThread()]
+        tup = self.parent.callinfo.get(trace.getCurrentThread(), None)
+        if tup == None:
+            return
+
+        ret_addr, args = tup
 
         self.runPostHookCallbacks(event, trace, ret_addr, args)

vtrace/tests/tests_breakpoints.py

@@ -0,0 +1,21 @@
+import unittest
+
+import vtrace.breakpoints
+
+# TODO: move testmods.hookbptest tests in here as well.
+
+class MockTrace(object):
+    def getCurrentThread(self):
+        return 0
+
+class HookBpPostTests(unittest.TestCase):
+    def test_PostHitNoCallinfo(self):
+        '''
+        tests condition where:
+        1. thread 1 hits hookbp and sets up postbp
+        2. thread 2 hits postbp (there's nothing in callinfo for thread 2)
+        '''
+        hbp = vtrace.breakpoints.HookBreakpoint('0xdeadbeef')
+        phbp = vtrace.breakpoints.PostHookBreakpoint('0xcafebabe', hbp)
+
+        phbp.notify(None, MockTrace())