[PATCH] localrepo: abort when processing incomplete bundle - don't crash

[Mads Kiilerich]

# HG changeset patch
# User Mads Kiilerich <mads at kiilerich.com>
# Date 1298246797 -3600
# Branch stable
# Node ID 0c1a5b0caff4d01f74b31b21ff1e49e8cae8cb6b
# Parent  61a89857688898c298bfa5cc3e3a90197cfcf687
localrepo: abort when processing incomplete bundle - don't crash

Mercurial http servers will for some reason sometimes send incomplete bundles.
hg used to crash, usually in changegroup.py:173 parsechunk with:
  struct.error: unpack requires a string argument of length 80
or in revlog.py:1005 _addrevision with:
  mpatch.mpatchError: patch cannot be decoded

With this change we intercept these exceptions at a higher level and try to
give a hint what the problem is:
  error processing received changelog group

diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -10,7 +10,7 @@
 import repo, changegroup, subrepo, discovery, pushkey
 import changelog, dirstate, filelog, manifest, context, bookmarks
 import lock, transaction, store, encoding
-import util, extensions, hook, error
+import util, extensions, hook, error, mpatch, struct
 import match as matchmod
 import merge as mergemod
 import tags as tagsmod
@@ -1800,8 +1800,12 @@
             pr = prog()
             source.callback = pr
 
-            if (cl.addgroup(source, csmap, trp) is None
-                and not emptyok):
+            try:
+                node = cl.addgroup(source, csmap, trp)
+            except (mpatch.mpatchError, struct.error):
+                self.ui.traceback()
+                raise util.Abort(_("error processing received changelog group"))
+            if (node is None and not emptyok):
                 raise util.Abort(_("received changelog group is empty"))
             clend = len(cl)
             changesets = clend - clstart
diff --git a/mercurial/mpatch.c b/mercurial/mpatch.c
--- a/mercurial/mpatch.c
+++ b/mercurial/mpatch.c
@@ -464,7 +464,14 @@
 PyMODINIT_FUNC
 initmpatch(void)
 {
-	Py_InitModule3("mpatch", methods, mpatch_doc);
+	PyObject *m;
+
+	m = Py_InitModule3("mpatch", methods, mpatch_doc);
+	if (m == NULL)
+		return;
+
 	mpatch_Error = PyErr_NewException("mpatch.mpatchError", NULL, NULL);
+	Py_INCREF(mpatch_Error);
+	PyModule_AddObject(m, "mpatchError", mpatch_Error);
 }
 #endif