lib/message.cc: fix Coverity finding (use after free)

The object where pointer to `data` was received was deleted before
it was used in _notmuch_string_list_append().

Relevant Coverity messages follow:

3: extract
Assigning: data = std::__cxx11::string(message->doc.()).c_str(),
which extracts wrapped state from temporary of type std::__cxx11::string.

4: dtor_free
The internal representation of temporary of type std::__cxx11::string
is freed by its destructor.

5: use after free:
Wrapper object use after free (WRAPPER_ESCAPE)
Using internal representation of destroyed object local data.

diff --git a/lib/message.cc b/lib/message.cc
index 007f11715eb8f97d495f0ed68e1180e9fcc86452..36a07a8890b0dd52a092fc8c88434676cc4193be 100644 (file)
--- a/lib/message.cc
+++ b/lib/message.cc
@@ -870,9 +870,9 @@ _notmuch_message_ensure_filename_list (notmuch_message_t *message)
         *
         * It would be nice to do the upgrade of the document directly
         * here, but the database is likely open in read-only mode. */
-       const char *data;
 
-       data = message->doc.get_data ().c_str ();
+       std::string datastr = message->doc.get_data ();
+       const char *data = datastr.c_str ();
 
        if (data == NULL)
            INTERNAL_ERROR ("message with no filename");