NOTMUCH_STATUS_LAST_STATUS problematic across additive library upgrades

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+From: Daniel Kahn Gillmor <dkg@fifthhorseman.net>\r
+To: notmuch mailing list <notmuch@notmuchmail.org>\r
+Subject: NOTMUCH_STATUS_LAST_STATUS problematic across additive library\r
+ upgrades\r
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+Date: Mon, 07 Dec 2015 17:54:21 -0500\r
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+\r
+hi notmuch folks--\r
+\r
+notmuch_status_t is an enum that counts up to\r
+NOTMUCH_STATUS_LAST_STATUS.\r
+\r
+This is fine for work within the library itself, but it seems\r
+problematic to expose it to users of the library.\r
+\r
+In particular, if a user builds against version X of the library, then\r
+version X+1 is released with a new status code (but no\r
+backward-incompatible API/ABI changes that would require an SONAME\r
+bump), then the value of NOTMUCH_STATUS_LAST_STATUS would change, but\r
+the application using notmuch wouldn't know about it.\r
+\r
+Is this something we should be concerned about?  I don't know why or\r
+when a library user might try to make use of NOTMUCH_STATUS_LAST_STATUS,\r
+but it's also exposed in the go bindings, so it's leaking out quite a\r
+bit.\r
+\r
+   --dkg\r