# HG changeset patch
# User Jun Wu <quark@fb.com>
# Date 1493166881 25200
# Node ID 4195b84940e95b8b9aed5bc04b06b398edb5ce74
# Parent  f432897a9f4926c9abb58e1ca667a7fa1e5f91f0
bdiff: add version to help detect breaking binary changes

Previously, we have no way to detect if a compiled .so file could be used or
not, and blindly load it if it exists. Usually we carefully maintain
compatibility of .so and fallback to pure code gracefully. But if we stick
to the rules, certain nice changes will be impossible to make in a clean
way.

This patch adds a "version" constant to the module so we can detect
inconsistency and take appropriate actions (warn, abort, fallback to pure,
run make automatically) in module loader.

diff -r f432897a9f49 -r 4195b84940e9 mercurial/bdiff_module.c
--- a/mercurial/bdiff_module.c	Sat May 20 03:10:23 2017 +0200
+++ b/mercurial/bdiff_module.c	Tue Apr 25 17:34:41 2017 -0700
@@ -192,6 +192,8 @@
 	{NULL, NULL}
 };
 
+static const int version = 1;
+
 #ifdef IS_PY3K
 static struct PyModuleDef bdiff_module = {
 	PyModuleDef_HEAD_INIT,
@@ -203,11 +205,16 @@
 
 PyMODINIT_FUNC PyInit_bdiff(void)
 {
-	return PyModule_Create(&bdiff_module);
+	PyObject *m;
+	m = PyModule_Create(&bdiff_module);
+	PyModule_AddIntConstant(m, "version", version);
+	return m;
 }
 #else
 PyMODINIT_FUNC initbdiff(void)
 {
-	Py_InitModule3("bdiff", methods, mdiff_doc);
+	PyObject *m;
+	m = Py_InitModule3("bdiff", methods, mdiff_doc);
+	PyModule_AddIntConstant(m, "version", version);
 }
 #endif