[PATCH 3/8] lib: propagate error return from some calls to _n_m_e_metadata

[David Bremner <david@tethera.net>]

In this commit we take care of the easy cases, where _n_m_e_metadata
is called from a non-void function. Three tricker cases are left for
future commits.
---
 lib/message.cc | 15 +++++++++++----
 lib/notmuch.h  |  9 ++++-----
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/lib/message.cc b/lib/message.cc
index 916dd441..16ea980c 100644
--- a/lib/message.cc
+++ b/lib/message.cc
@@ -458,7 +458,9 @@ const char *
 notmuch_message_get_message_id (notmuch_message_t *message)
 {
     if (!message->message_id)
-	_notmuch_message_ensure_metadata (message);
+	if (_notmuch_message_ensure_metadata (message))
+	    return NULL;
+
     if (!message->message_id)
 	INTERNAL_ERROR ("Message with document ID of %u has no message ID.\n",
 			message->doc_id);
@@ -534,7 +536,9 @@ const char *
 _notmuch_message_get_in_reply_to (notmuch_message_t *message)
 {
     if (!message->in_reply_to)
-	_notmuch_message_ensure_metadata (message);
+	if (_notmuch_message_ensure_metadata (message))
+	    return NULL;
+
     return message->in_reply_to;
 }
 
@@ -542,7 +546,9 @@ const char *
 notmuch_message_get_thread_id (notmuch_message_t *message)
 {
     if (!message->thread_id)
-	_notmuch_message_ensure_metadata (message);
+	if (_notmuch_message_ensure_metadata (message))
+	    return NULL;
+
     if (!message->thread_id)
 	INTERNAL_ERROR ("Message with document ID of %u has no thread ID.\n",
 			message->doc_id);
@@ -982,7 +988,8 @@ notmuch_message_get_tags (notmuch_message_t *message)
     notmuch_tags_t *tags;
 
     if (!message->tag_list)
-	_notmuch_message_ensure_metadata (message);
+	if (_notmuch_message_ensure_metadata (message))
+	    return NULL;
 
     tags = _notmuch_tags_create (message, message->tag_list);
     /* _notmuch_tags_create steals the reference to the tag_list, but
diff --git a/lib/notmuch.h b/lib/notmuch.h
index 16da8be9..62866e5a 100644
--- a/lib/notmuch.h
+++ b/lib/notmuch.h
@@ -1286,9 +1286,7 @@ notmuch_messages_collect_tags (notmuch_messages_t *messages);
  * message is valid, (which is until the query from which it derived
  * is destroyed).
  *
- * This function will not return NULL since Notmuch ensures that every
- * message has a unique message ID, (Notmuch will generate an ID for a
- * message if the original file does not contain one).
+ * The function returns NULL on error.
  */
 const char *
 notmuch_message_get_message_id (notmuch_message_t *message);
@@ -1302,8 +1300,7 @@ notmuch_message_get_message_id (notmuch_message_t *message);
  * notmuch_message_destroy on 'message' or until a query from which it
  * derived is destroyed).
  *
- * This function will not return NULL since Notmuch ensures that every
- * message belongs to a single thread.
+ * The function returns NULL on error.
  */
 const char *
 notmuch_message_get_thread_id (notmuch_message_t *message);
@@ -1449,6 +1446,8 @@ notmuch_message_get_header (notmuch_message_t *message, const char *header);
  * notmuch_tags_t object. (For consistency, we do provide a
  * notmuch_tags_destroy function, but there's no good reason to call
  * it if the message is about to be destroyed).
+ *
+ * The function returns NULL on error.
  */
 notmuch_tags_t *
 notmuch_message_get_tags (notmuch_message_t *message);
-- 
2.11.0