Re: [PATCH v3 04/13] lib: Database version 3: Introduce fine-grained "features"

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+From: David Bremner <david@tethera.net>\r
+To: Austin Clements <amdragon@mit.edu>, notmuch@notmuchmail.org\r
+Subject: Re: [PATCH v3 04/13] lib: Database version 3: Introduce fine-grained\r
+       "features"\r
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+Austin Clements <amdragon@mit.edu> writes:\r
+\r
+>>> @@ -1048,7 +1164,8 @@ notmuch_database_get_version (notmuch_database_t *notmuch)\r
+>>>  notmuch_bool_t\r
+>>>  notmuch_database_needs_upgrade (notmuch_database_t *notmuch)\r
+>>>  {\r
+>>> -    return notmuch->needs_upgrade;\r
+>>> +    return notmuch->mode == NOTMUCH_DATABASE_MODE_READ_WRITE &&\r
+>>> +  (NOTMUCH_FEATURES_CURRENT & ~notmuch->features);\r
+>>>  }\r
+>>\r
+>> Maybe I'm not thinking hard enough here, but how does this deal with a\r
+>> feature that is needed to open a database in read only mode? Maybe it\r
+>> needs a comment for people not as clever as Austin ;).\r
+>\r
+> I'm not quite sure what you mean.  notmuch_database_needs_upgrade\r
+> returns false for read-only databases because you can't upgrade a\r
+> read-only database.  This was true before this patch, too, though it was\r
+> less obvious.  (Maybe that's not what you're asking?)\r
+\r
+Yes, that's what I was asking. I guess it's orthogonal to your patch\r
+series, but the logic of returning FALSE for read only databases is not\r
+very intuitive to me (in the sense that "needs upgrade" is not the\r
+opposite of "can't be upgraded".  Your new comment later in the series\r
+is better, but it would IMHO be even better if you mentioned the read\r
+only case.\r
+\r
+d\r