lib: support splitting mail from database location.

Introduce a new configuration value for the mail root, and use it to
locate mail messages in preference to the database.path (which
previously implied the mail messages were also in this location.

Initially only a subset of the CLI is tested in a split
configuration. Further changes will be needed for the remainder of the
CLI to work in split configurations.

1 files changed, 12 insertions, 3 deletions

diff --git a/doc/man1/notmuch-config.rst b/doc/man1/notmuch-config.rst
index bc597957..223d2de5 100644
--- a/doc/man1/notmuch-config.rst
+++ b/doc/man1/notmuch-config.rst
@@ -43,12 +43,21 @@ configuration file and corresponding database.
 The available configuration items are described below.
 
 **database.path**
+    Notmuch will store its database here, (in
+    sub-directory named ``.notmuch`` if **database.mail\_root**
+    is unset).
+
+    Default: ``$MAILDIR`` variable if set, otherwise ``$HOME/mail``.
+
+**database.mail_root**
     The top-level directory where your mail currently exists and to
     where mail will be delivered in the future. Files should be
-    individual email messages. Notmuch will store its database within
-    a sub-directory of the path configured here named ``.notmuch``.
+    individual email messages.
 
-    Default: ``$MAILDIR`` variable if set, otherwise ``$HOME/mail``.
+    History: this configuration value was introduced in notmuch 0.32.
+
+    Default: For compatibility with older configurations, the value of
+    database.path is used if **database.mail\_root** is unset.
 
 **database.hook_dir**