From f5a133608a72a96b2023024043dc00480192bcc7 Mon Sep 17 00:00:00 2001
From: Mark Wooding <mdw@distorted.org.uk>
Date: Mon, 25 Nov 2019 11:54:12 +0000
Subject: [PATCH] key.c: Complain about duplicate subkeys passed to
 `KeyDataStructured'.

This wasn't previously possible (without complicated subterfuge), but
now a keyword argument can duplicate a mapping set in the positional
argument.
---
 key.c      | 1 +
 t/t-key.py | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/key.c b/key.c
index d97d632..017c973 100644
--- a/key.c
+++ b/key.c
@@ -1029,6 +1029,7 @@ static int populate_struct(key_data *kd, PyObject *map)
       goto end;
     if (!KEYDATA_PYCHECK(val))
       TYERR("subkey objects must be instances of KeyData");
+    if (key_structfind(kd, p)) VALERR("duplicate tag");
     key_structset(kd, p, KEYDATA_KD(val));
     Py_DECREF(name); name = 0;
     Py_DECREF(val); val = 0;
diff --git a/t/t-key.py b/t/t-key.py
index 9e3646f..000dc11 100644
--- a/t/t-key.py
+++ b/t/t-key.py
@@ -295,6 +295,9 @@ class TestKeyData (U.TestCase):
     me.assertEqual(len(kd), 4)
     me.check_encode(kd)
     me.assertRaises(TypeError, C.KeyDataStructured, { "a": "a" })
+    me.assertRaises(ValueError, C.KeyDataStructured,
+                    { "a": C.KeyDataString("a") },
+                    a = C.KeyDataString("b"))
 
 ###--------------------------------------------------------------------------
 ### Mappings.
-- 
2.11.0