update faq entry about searching for messages without tags

[notmuch-wiki] / faq.mdwn

diff --git a/faq.mdwn b/faq.mdwn
index 6862685841982e3390179d6b3571bd075f3eaf71..2e7fa10a03424e80f43493122931f9c295e8c0b9 100644 (file)
--- a/faq.mdwn
+++ b/faq.mdwn
@@ -27,11 +27,26 @@ See [[excluding]].
 
 See help for `message-citation-line-format` for details.
 
+## What are sexp queries
+
+For the syntax of sexp queries, see [the manual
+page](https://notmuchmail.org/doc/latest/man7/notmuch-sexp-queries.html).
+
+To see if your version of notmuch supports them, run
+
+        $ notmuch config get built_with.sexp_queries
+
 ## How do I search for messages that have no tags?
 
-Unfortunately, there is no way to do this directly.
+To do this directly, you need a recent notmuch compiled with sexp
+queries (see above). You can then run
 
-However, it's possible to accomplish this using two searches in shell. First,
+        $ notmuch search --query=sexp --output=messages '(not (tag *))'
+
+The same style of query should work for any prefix, even user defined
+prefixes like `List` (see below).
+
+Otherwise, it's possible to accomplish this using two searches in shell. First,
 you need to query all tags in the database, and transform the result into a
 query that matches messages that have none of those tags:
 
@@ -64,18 +79,9 @@ with this query:
 
 ## How do I search for the `List-Id:` header?
 
-Currently there is no way to search for `List-Id:`. As a workaround, try using a
-`to:` prefix search (which covers both `To:` and `Cc:` headers) on the mailing
-list address.
+See `index.header.<prefix>` in `notmuch-config(1)` for details. TLD;R:
 
-Limitations in the duplicate message handling are the main reason for not
-indexing the `List-Id:` header. If you receive the same message via both the
-list and directly (by way of `To:` or `Cc:`), only the first message encountered
-will be indexed. Only the message received via the list will have `List-Id:`,
-but you would expect a `List-Id:` search to find the message, regardless of the
-order in which the duplicates were received. This is a more general problem than
-just `List-Id:`, and once this has been resolved, adding `List-Id:` indexing is
-trivial.
+    notmuch config set index.header.List List-Id
 
 ## Can I use notmuch with grsec?
 
@@ -107,3 +113,24 @@ stop it from propagating again.
 
 See [notmuch-extract-patch](https://github.com/aaptel/notmuch-extract-patch).
 
+## T150-tagging.sh is failing with Xapian 1.4.6
+
+This is (probably) a bug in this point release of Xapian, should be
+fixed in 1.4.7.  Try reverting Xapian commit
+`093999529acc2f86900d91fed0c7f7af301ab94a`, e.g. with the following
+patch.
+
+
+    index 80e578b85..a47f14a68 100644
+    --- a/xapian-core/backends/glass/glass_postlist.cc
+    +++ b/xapian-core/backends/glass/glass_postlist.cc
+    @@ -759,7 +759,7 @@ GlassPostList::open_nearby_postlist(const std::string & term_,
+         (void)need_pos;
+         if (term_.empty())
+            RETURN(NULL);
+    -    if (!this_db.get() || this_db->postlist_table.is_modified())
+    +    if (!this_db.get() || this_db->postlist_table.is_writable())
+            RETURN(NULL);
+         RETURN(new GlassPostList(this_db, term_, cursor->clone()));
+     }
+