Long story short, fix build on recent (3.2+) clang.
The long story for posterity follows.
gcc 4.6 added new warnings about structs with greater visibility than
their fields. The warnings were silenced by adjusting visibility in
commit d5523ead90b6be2b07d4af745b8ed9b980a6b9f1
Author: Carl Worth <cworth@cworth.org>
Date: Wed May 11 13:23:13 2011 -0700
Mark some structures in the library interface with visibility=default attribute.
Later on,
commit 3b76adf9e2c026dd03b820f4c6eab50e25444113
Author: Austin Clements <amdragon@MIT.EDU>
Date: Sat Jan 14 19:17:33 2012 -0500
lib: Add support for automatically excluding tags from queries
changed visibility of struct _notmuch_string_list for the same reason, and
commit 1a53f9f116fa7c460cda3df532be921baaafb082
Author: Mark Walters <markwalters1009@gmail.com>
Date: Thu Mar 1 22:30:38 2012 +0000
lib: Add the exclude flag to notmuch_query_search_threads
split the struct _notmuch_string_list and its typedef
notmuch_string_list_t as a way to make a forward declaration for
_notmuch_thread_create().
The subtle difference was that the struct definition now had 'visible'
in it, while the typedef didn't, and it was within the #pragma GCC
visibility push(hidden) block. This went unnoticed, as the then common
versions of clang didn't care about this.
A later change in clang (I did not dig into when this change was
introduced) caused the following error:
CXX -O2 lib/database.o
In file included from lib/database.cc:21:
In file included from ./lib/database-private.h:33:
./lib/notmuch-private.h:479:8: error: visibility does not match previous declaration
struct visible _notmuch_string_list {
^
./lib/notmuch-private.h:67:33: note: expanded from macro 'visible'
^
./lib/notmuch-private.h:52:13: note: previous attribute is here
^
1 error generated.
make: *** [lib/database.o] Error 1
This is slightly misleading due to the reference to the #pragma. The
real culprit is the typedef within the #pragma.
We could just add 'visible' to the typedef, or move the typedef
outside of the #pragma, and be done with it, but juggle the
declarations a bit to accommodate moving the typedef back with the
struct, and keep the visibility attribute in one place.
The problem was originally reported by Simonas Kazlauskas
<s@kazlauskas.me> in id:20130418102507.GA23688@godbox but I was only
able to reproduce and investigate now that I upgraded clang.
---
lib/notmuch-private.h | 28 +++++++++++++---------------
1 file changed, 13 insertions(+), 15 deletions(-)
diff --git a/lib/notmuch-private.h b/lib/notmuch-private.h
index eced03e..af185c7 100644
--- a/lib/notmuch-private.h
+++ b/lib/notmuch-private.h
@@ -162,8 +162,6 @@ typedef enum _notmuch_find_flags {
typedef struct _notmuch_doc_id_set notmuch_doc_id_set_t;
-typedef struct _notmuch_string_list notmuch_string_list_t;
-
/* database.cc */
/* Lookup a prefix value by name.
@@ -228,17 +226,6 @@ _notmuch_directory_create (notmuch_database_t *notmuch,
unsigned int
_notmuch_directory_get_document_id (notmuch_directory_t *directory);
-/* thread.cc */
-
-notmuch_thread_t *
-_notmuch_thread_create (void *ctx,
- notmuch_database_t *notmuch,
- unsigned int seed_doc_id,
- notmuch_doc_id_set_t *match_set,
- notmuch_string_list_t *excluded_terms,
- notmuch_exclude_t omit_exclude,
- notmuch_sort_t sort);
-
/* message.cc */
notmuch_message_t *
@@ -476,11 +463,11 @@ typedef struct _notmuch_string_node {
struct _notmuch_string_node *next;
} notmuch_string_node_t;
-struct visible _notmuch_string_list {
+typedef struct visible _notmuch_string_list {
int length;
notmuch_string_node_t *head;
notmuch_string_node_t **tail;
-};
+} notmuch_string_list_t;
notmuch_string_list_t *
_notmuch_string_list_create (const void *ctx);
@@ -509,6 +496,17 @@ notmuch_filenames_t *
_notmuch_filenames_create (const void *ctx,
notmuch_string_list_t *list);
+/* thread.cc */
+
+notmuch_thread_t *
+_notmuch_thread_create (void *ctx,
+ notmuch_database_t *notmuch,
+ unsigned int seed_doc_id,
+ notmuch_doc_id_set_t *match_set,
+ notmuch_string_list_t *excluded_terms,
+ notmuch_exclude_t omit_exclude,
+ notmuch_sort_t sort);
+
NOTMUCH_END_DECLS
#ifdef __cplusplus
--
1.7.10.4