From 307fcbf4e71fe32585f2bc3138231f6de43681ed Mon Sep 17 00:00:00 2001
From: Jason Paryani <github@jparyani.com>
Date: Tue, 18 Feb 2014 17:34:34 -0800
Subject: [PATCH] Fix problem with uninitialized unions in _from_dict

---
 capnp/lib/capnp.pyx    | 7 ++++++-
 test/addressbook.capnp | 7 ++++++-
 test/test_struct.py    | 6 ++++++
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/capnp/lib/capnp.pyx b/capnp/lib/capnp.pyx
index 525c653..88bd7e9 100644
--- a/capnp/lib/capnp.pyx
+++ b/capnp/lib/capnp.pyx
@@ -741,7 +741,12 @@ cdef _to_dict(msg, bint verbose):
 cdef _from_dict(_DynamicStructBuilder msg, dict d):
     for key, val in d.iteritems():
         if key != 'which':
-            msg._set(key, val)
+            try:
+                msg._set(key, val)
+            except Exception as e:
+                if 'expected isSetInUnion(field)' in str(e):
+                    msg.init(key)
+                    msg._set(key, val)
 
 cdef _from_list(_DynamicListBuilder msg, list d):
     cdef size_t count = 0
diff --git a/test/addressbook.capnp b/test/addressbook.capnp
index e1cd77c..b50b68b 100644
--- a/test/addressbook.capnp
+++ b/test/addressbook.capnp
@@ -21,13 +21,18 @@ struct Person {
 
   employment :union {
     unemployed @4 :Void;
-    employer @5 :Text;
+    employer @5 :Employer;
     school @6 :Text;
     selfEmployed @7 :Void;
     # We assume that a person is only one of these.
   }
 }
 
+struct Employer {
+  name @0 :Text;
+  boss @1 :Person;
+}
+
 struct AddressBook {
   people @0 :List(Person);
 }
diff --git a/test/test_struct.py b/test/test_struct.py
index 51533d7..f73e4f2 100644
--- a/test/test_struct.py
+++ b/test/test_struct.py
@@ -164,3 +164,9 @@ def test_set_dict(all_types):
     msg.structList[0] = {'int32Field': 102}
 
     assert msg.structList[0].int32Field == 102
+
+
+def test_set_dict_union(addressbook):
+    person = addressbook.Person.new_message(**{'employment': {'employer': {'name': 'foo'}}})
+
+    assert person.employment.employer.name == 'foo'