notmuch_database_close may fail in Xapian ->flush() or ->close(), so
report the status. Similarly for notmuch_database_destroy which calls
close.

This is required for notmuch insert to report error status if message
indexing failed.

Bump the notmuch version to allow clients to conditional build against
both the current release and the next release (current git master).
---
 lib/database.cc | 18 ++++++++++++++----
 lib/notmuch.h   | 17 ++++++++++++++---
 2 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/lib/database.cc b/lib/database.cc
index f395061..98e2c31 100644
--- a/lib/database.cc
+++ b/lib/database.cc
@@ -767,14 +767,17 @@ notmuch_database_open (const char *path,
     return status;
 }
 
-void
+notmuch_status_t
 notmuch_database_close (notmuch_database_t *notmuch)
 {
+    notmuch_status_t status = NOTMUCH_STATUS_SUCCESS;
+
     try {
 	if (notmuch->xapian_db != NULL &&
 	    notmuch->mode == NOTMUCH_DATABASE_MODE_READ_WRITE)
 	    (static_cast <Xapian::WritableDatabase *> (notmuch->xapian_db))->flush ();
     } catch (const Xapian::Error &error) {
+	status = NOTMUCH_STATUS_XAPIAN_EXCEPTION;
 	if (! notmuch->exception_reported) {
 	    fprintf (stderr, "Error: A Xapian exception occurred flushing database: %s\n",
 		     error.get_msg().c_str());
@@ -789,6 +792,7 @@ notmuch_database_close (notmuch_database_t *notmuch)
 	    notmuch->xapian_db->close();
 	} catch (const Xapian::Error &error) {
 	    /* do nothing */
+	    status = NOTMUCH_STATUS_XAPIAN_EXCEPTION;
 	}
     }
 
@@ -802,6 +806,8 @@ notmuch_database_close (notmuch_database_t *notmuch)
     notmuch->value_range_processor = NULL;
     delete notmuch->date_range_processor;
     notmuch->date_range_processor = NULL;
+
+    return status;
 }
 
 #if HAVE_XAPIAN_COMPACT
@@ -966,7 +972,7 @@ notmuch_database_compact (const char *path,
 
   DONE:
     if (notmuch)
-	notmuch_database_destroy (notmuch);
+	ret = notmuch_database_destroy (notmuch);
 
     talloc_free (local);
 
@@ -984,11 +990,15 @@ notmuch_database_compact (unused (const char *path),
 }
 #endif
 
-void
+notmuch_status_t
 notmuch_database_destroy (notmuch_database_t *notmuch)
 {
-    notmuch_database_close (notmuch);
+    notmuch_status_t status;
+
+    status = notmuch_database_close (notmuch);
     talloc_free (notmuch);
+
+    return status;
 }
 
 const char *
diff --git a/lib/notmuch.h b/lib/notmuch.h
index 7c3a30c..dbdce86 100644
--- a/lib/notmuch.h
+++ b/lib/notmuch.h
@@ -42,7 +42,7 @@ NOTMUCH_BEGIN_DECLS
 #endif
 
 #define NOTMUCH_MAJOR_VERSION	0
-#define NOTMUCH_MINOR_VERSION	17
+#define NOTMUCH_MINOR_VERSION	18
 #define NOTMUCH_MICRO_VERSION	0
 
 /*
@@ -236,8 +236,16 @@ notmuch_database_open (const char *path,
  *
  * notmuch_database_close can be called multiple times.  Later calls
  * have no effect.
+ *
+ * Return value:
+ *
+ * NOTMUCH_STATUS_SUCCESS: Successfully closed the database.
+ *
+ * NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception occurred; the
+ *	database has been closed but there are no guarantees the
+ *	changes to the database, if any, have been flushed to disk.
  */
-void
+notmuch_status_t
 notmuch_database_close (notmuch_database_t *database);
 
 /* A callback invoked by notmuch_database_compact to notify the user
@@ -263,8 +271,11 @@ notmuch_database_compact (const char* path,
 
 /* Destroy the notmuch database, closing it if necessary and freeing
  * all associated resources.
+ *
+ * Return value as in notmuch_database_close if the database was open;
+ * notmuch_database_destroy itself has no failure modes.
  */
-void
+notmuch_status_t
 notmuch_database_destroy (notmuch_database_t *database);
 
 /* Return the database path of the given database.
-- 
1.8.4.2