Add 'git format-patch --to=' option and 'format.to' configuration variable.

Has the same functionality as the '--cc' option and 'format.cc'
configuration variable but for the "To:" email header.  Half of the code to
support this was already there.

With email the To: header usually more important than the Cc: header.

[jc: tests are by Stephen Boyd]

Signed-off-by: Steven Drake <sdrake@xnet.co.nz>
Signed-off-by: Stephen Boyd <bebarino@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-format-patch.txt

@@ -18,7 +18,7 @@ SYNOPSIS
 		   [--in-reply-to=Message-Id] [--suffix=.<sfx>]
 		   [--ignore-if-in-upstream]
 		   [--subject-prefix=Subject-Prefix]
-		   [--cc=<email>]
+		   [--to=<email>] [--cc=<email>]
 		   [--cover-letter]
 		   [<common diff options>]
 		   [ <since> | <revision range> ]
@@ -162,6 +162,10 @@ will want to ensure that threading is disabled for `git send-email`.
 	allows for useful naming of a patch series, and can be
 	combined with the `--numbered` option.
 
+--to=<email>::
+	Add a `To:` header to the email headers. This is in addition
+	to any configured headers, and may be used multiple times.
+
 --cc=<email>::
 	Add a `Cc:` header to the email headers. This is in addition
 	to any configured headers, and may be used multiple times.
@@ -202,8 +206,8 @@ CONFIGURATION
 -------------
 You can specify extra mail header lines to be added to each message,
 defaults for the subject prefix and file suffix, number patches when
-outputting more than one patch, add "Cc:" headers, configure attachments,
-and sign off patches with configuration variables.
+outputting more than one patch, add "To" or "Cc:" headers, configure
+attachments, and sign off patches with configuration variables.
 
 ------------
 [format]
@@ -211,6 +215,7 @@ and sign off patches with configuration variables.
 	subjectprefix = CHANGE
 	suffix = .txt
 	numbered = auto
+	to = <email>
 	cc = <email>
 	attach [ = mime-boundary-string ]
 	signoff = true

builtin-log.c

@@ -504,6 +504,13 @@ static int git_format_config(const char *var, const char *value, void *cb)
 	}
 	if (!strcmp(var, "format.suffix"))
 		return git_config_string(&fmt_patch_suffix, var, value);
+	if (!strcmp(var, "format.to")) {
+		if (!value)
+			return config_error_nonbool(var);
+		ALLOC_GROW(extra_to, extra_to_nr + 1, extra_to_alloc);
+		extra_to[extra_to_nr++] = xstrdup(value);
+		return 0;
+	}
 	if (!strcmp(var, "format.cc")) {
 		if (!value)
 			return config_error_nonbool(var);
@@ -875,6 +882,13 @@ static int header_callback(const struct option *opt, const char *arg, int unset)
 	return 0;
 }
 
+static int to_callback(const struct option *opt, const char *arg, int unset)
+{
+	ALLOC_GROW(extra_to, extra_to_nr + 1, extra_to_alloc);
+	extra_to[extra_to_nr++] = xstrdup(arg);
+	return 0;
+}
+
 static int cc_callback(const struct option *opt, const char *arg, int unset)
 {
 	ALLOC_GROW(extra_cc, extra_cc_nr + 1, extra_cc_alloc);
@@ -939,6 +953,8 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 		{ OPTION_CALLBACK, 0, "add-header", NULL, "header",
 			    "add email header", PARSE_OPT_NONEG,
 			    header_callback },
+		{ OPTION_CALLBACK, 0, "to", NULL, "email", "add To: header",
+			    PARSE_OPT_NONEG, to_callback },
 		{ OPTION_CALLBACK, 0, "cc", NULL, "email", "add Cc: header",
 			    PARSE_OPT_NONEG, cc_callback },
 		OPT_STRING(0, "in-reply-to", &in_reply_to, "message-id",

t/t4014-format-patch.sh

@@ -143,6 +143,20 @@ test_expect_success 'configuration headers and command line headers' '
 	grep "^ *S. E. Cipient <scipient@example.com>\$" patch7
 '
 
+test_expect_success 'command line To: header' '
+
+	git config --unset-all format.headers &&
+	git format-patch --to="R. E. Cipient <rcipient@example.com>" --stdout master..side | sed -e "/^\$/q" >patch8 &&
+	grep "^To: R. E. Cipient <rcipient@example.com>\$" patch8
+'
+
+test_expect_success 'configuration To: header' '
+
+	git config format.to "R. E. Cipient <rcipient@example.com>" &&
+	git format-patch --stdout master..side | sed -e "/^\$/q" >patch9 &&
+	grep "^To: R. E. Cipient <rcipient@example.com>\$" patch9
+'
+
 test_expect_success 'multiple files' '
 
 	rm -rf patches/ &&