Improve doc for format-patch threading options.

[git.git] / Documentation / git-send-email.txt

diff --git a/Documentation/git-send-email.txt b/Documentation/git-send-email.txt
index fbde2d3be523443c8388f9bb43cc0d5682658f8f..d6b192b7b9d6c7d67703b5e2984a9fed7ffcea3b 100644 (file)
--- a/Documentation/git-send-email.txt
+++ b/Documentation/git-send-email.txt
@@ -212,11 +212,22 @@ specified, as well as 'body' if --no-signed-off-cc is specified.
        value; if that is unspecified, default to --no-suppress-from.
 
 --[no-]thread::
-       If this is set, the In-Reply-To header will be set on each email sent.
-       If disabled with "--no-thread", no emails will have the In-Reply-To
-       header set, unless specified with --in-reply-to.
-       Default is the value of the 'sendemail.thread' configuration
-       value; if that is unspecified, default to --thread.
+       If this is set, the In-Reply-To and References headers will be
+       added to each email sent.  Whether each mail refers to the
+       previous email (`deep` threading per 'git format-patch'
+       wording) or to the first email (`shallow` threading) is
+       governed by "--[no-]chain-reply-to".
++
+If disabled with "--no-thread", those headers will not be added
+(unless specified with --in-reply-to).  Default is the value of the
+'sendemail.thread' configuration value; if that is unspecified,
+default to --thread.
++
+It is up to the user to ensure that no In-Reply-To header already
+exists when 'git send-email' is asked to add it (especially note that
+'git format-patch' can be configured to do the threading itself).
+Failure to do so may not produce the expected result in the
+recipient's MUA.
 
 
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