[PATCH v5 1/6] restore: Make missing messages non-fatal (again)

[Austin Clements]

Previously, restore would abort if a message ID in the dump was
missing.  Furthermore, it would only report this as a warning.  This
patch makes it distinguish abort-worthy lookup failures like
out-of-memory from non-fatal failure to find a message ID.  The former
is reported as an error and causes restore to abort, while the latter
is reported as a warning and does not cause an abort.

This restores 0.14's non-fatal handling of missing message IDs in
restore (though 0.14 also considered serious errors non-fatal; we
retain the new and better handling of serious errors).
---
 notmuch-restore.c |   17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/notmuch-restore.c b/notmuch-restore.c
index 9ed9b51..96834c0 100644
--- a/notmuch-restore.c
+++ b/notmuch-restore.c
@@ -26,7 +26,8 @@
 static regex_t regex;
 
 /* Non-zero return indicates an error in retrieving the message,
- * or in applying the tags.
+ * or in applying the tags.  Missing messages are reported, but not
+ * considered errors.
  */
 static int
 tag_message (unused (void *ctx),
@@ -40,13 +41,17 @@ tag_message (unused (void *ctx),
     int ret = 0;
 
     status = notmuch_database_find_message (notmuch, message_id, &message);
-    if (status || message == NULL) {
-	fprintf (stderr, "Warning: cannot apply tags to %smessage: %s\n",
-		 message ? "" : "missing ", message_id);
-	if (status)
-	    fprintf (stderr, "%s\n", notmuch_status_to_string (status));
+    if (status) {
+	fprintf (stderr, "Error applying tags to message %s: %s\n",
+		 message_id, notmuch_status_to_string (status));
 	return 1;
     }
+    if (message == NULL) {
+	fprintf (stderr, "Warning: cannot apply tags to missing message: %s\n",
+		 message_id);
+	/* We consider this a non-fatal error. */
+	return 0;
+    }
 
     /* In order to detect missing messages, this check/optimization is
      * intentionally done *after* first finding the message. */
-- 
1.7.10.4