[mailman3] Fix index not being rebuilt

The index build was failing on xapian_haystack issue that happens when
the mail is too long. This patch will skip those e-mails. See
infra/tickets#13355 for more info.

Signed-off-by: Michal Konecny <mkonecny@redhat.com>

roles/mailman3/files/mailman_patch/xapian_haystack_term_too_long.patch

@@ -0,0 +1,16 @@
+diff --git i/xapian_backend.py w/xapian_backend.py
+index 05e8fed..c2bdd95 100755
+--- i/xapian_backend.py
++++ w/xapian_backend.py
+@@ -498,7 +498,10 @@ class XapianSearchBackend(BaseSearchBackend):
+                 document.add_term(document_id)
+ 
+                 # finally, replace or add the document to the database
+-                database.replace_document(document_id, document)
++                try:
++                    database.replace_document(document_id, document)
++                except xapian.InvalidArgumentError as ex:
++                    sys.stderr.write(str(ex) + '\n')
+ 
+         except UnicodeDecodeError:
+             sys.stderr.write('Chunk failed.\n')

roles/mailman3/tasks/main.yml

@@ -436,6 +436,16 @@
   notify:
     - Restart mailman3
 
+# This is needed till https://github.com/notanumber/xapian-haystack/issues/77
+# is resolved
+- name: Apply xapian_haystack patch
+  ansible.posix.patch:
+    src: mailman3_patch/xapian_haystack_term_too_long.patch
+    basedir: /usr/lib/python3.9/site-packages/
+  tags:
+    - mailman
+    - patch
+
 # Memcached
 - name: Set the memcached sysconfig file
   ansible.builtin.copy: