git-am documentation: describe what is taken from where.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/Documentation/git-am.txt b/Documentation/git-am.txt
index 13a738986776b931d1dc16f0aac3804e384d924c..148ce405681cd4f5bd38575b6a427a7e5745a109 100644 (file)
--- a/Documentation/git-am.txt
+++ b/Documentation/git-am.txt
@@ -87,6 +87,33 @@ default.   You could use `--no-utf8` to override this.
 DISCUSSION
 ----------
 
 DISCUSSION
 ----------
 

+The commit author name is taken from the "From: " line of the
+message, and commit author time is taken from the "Date: " line
+of the message.  The "Subject: " line is used as the title of
+the commit, after stripping common prefix "[PATCH <anything>]".
+It is supposed to describe what the commit is about concisely as
+a one line text.
+
+The body of the message (iow, after a blank line that terminates
+RFC2822 headers) can begin with "Subject: " and "From: " lines
+that are different from those of the mail header, to override
+the values of these fields.
+
+The commit message is formed by the title taken from the
+"Subject: ", a blank line and the body of the message up to
+where the patch begins.  Excess whitespaces at the end of the
+lines are automatically stripped.
+
+The patch is expected to be inline, directly following the
+message.  Any line that is of form:
+
+* three-dashes and end-of-line, or
+* a line that begins with "diff -", or
+* a line that begins with "Index: "
+
+is taken as the beginning of a patch, and the commit log message
+is terminated before the first occurrence of such a line.
+

 When initially invoking it, you give it names of the mailboxes
 to crunch.  Upon seeing the first patch that does not apply, it
 aborts in the middle, just like 'git-applymbox' does.  You can
 When initially invoking it, you give it names of the mailboxes
 to crunch.  Upon seeing the first patch that does not apply, it
 aborts in the middle, just like 'git-applymbox' does.  You can