[Evolution-hackers] EWS MessageInfo leak wtf

[David Woodhouse <dwmw2 infradead org>]

==5510== 41 bytes in 1 blocks are possibly lost in loss record 8,473 of 17,762
==5510==    at 0x4A05E46: malloc (vg_replace_malloc.c:195)
==5510==    by 0x3B6A048B52: g_malloc (gmem.c:164)
==5510==    by 0x3B6A06101D: g_strdup (gstrfuncs.c:102)
==5510==    by 0x1693D7B1: ews_message_info_clone (camel-ews-summary.c:75)
==5510==    by 0x1693E4FD: camel_ews_summary_add_message_info (camel-ews-summary.c:417)
==5510==    by 0x16940ADD: camel_ews_utils_sync_created_items (camel-ews-utils.c:973)
==5510==    by 0x16939819: sync_created_items (camel-ews-folder.c:660)
==5510==    by 0x16939B41: ews_refresh_info_sync (camel-ews-folder.c:750)
==5510==    by 0x4C78C99: camel_folder_refresh_info (camel-folder.c:1156)
==5510==    by 0x33B6E7F0F7: mail_msg_proxy (mail-mt.c:469)
==5510==    by 0x3B6A06BBC3: g_thread_pool_thread_proxy (gthreadpool.c:319)
==5510==    by 0x3B6A069445: g_thread_create_proxy (gthread.c:1897)
==5510== 

Can't repeat it; don't know how it happened... except of course that it
obviously happened when SyncFolderItems returned some created items.

The frame in ews_message_info_clone() at camel_ews_summary:75 is setting
mi->change_key on the newly cloned MessageInfo:
http://git.infradead.org/evolution-ews.git/blob/cd1face:/src/camel/camel-ews-summary.c#l75

(I'm also *sure* it happened after commit 17bd5273 in which I fixed a
consistent leak of our mi->change_key by adding a message_info_free()
method to our class. Not only do I remember it that way, but the
timestamp of my valgrind log file is about four hours later than that
commit, and the *other* valgrind warnings that the ->change_key leak
caused are noticeable in their absence.)

I'm confused by the use of camel_message_info_clone() in the first line
of camel_ews_summary_add_message_info():
http://git.infradead.org/evolution-ews.git/blob/cd1face:/src/camel/camel-ews-summary.c#l417
There is *one* caller of this function, and it's the one in the above
backtrace — camel_ews_utils_sync_create_items():
http://git.infradead.org/evolution-ews.git/blob/cd1face:/src/camel/camel-ews-utils.c#l973

And that *creates* a new MessageInfo of its own... which AFAICT never
gets freed, although valgrind doesn't seem to be complaining about that,
and I don't know why.

Removing the clone in camel_ews_summary_add_message_info() and just
using '(void *)info' seems to work just as well; I'm not really sure
what's going on here. And either way, I've never been able to repeat the
above warning.

Chen, was there a reason for the clone? And why isn't valgrind
complaining about it? Can anyone see something that would cause the
above complaint that it *did* make?

-- 
dwmw2