mailinfo: allow squelching quoted CRLF warning

In previous change, Git starts to warn for quoted CRLF in decoded
base64/QP email. Despite those warnings are usually helpful,
quoted CRLF could be part of some users' workflow.

Let's give them an option to turn off the warning completely.

Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-mailinfo.txt

@@ -9,7 +9,9 @@ git-mailinfo - Extracts patch and authorship from a single e-mail message
 SYNOPSIS
 --------
 [verse]
-'git mailinfo' [-k|-b] [-u | --encoding=<encoding> | -n] [--[no-]scissors] <msg> <patch>
+'git mailinfo' [-k|-b] [-u | --encoding=<encoding> | -n]
+	       [--[no-]scissors] [--quoted-cr=<action>]
+	       <msg> <patch>
 
 
 DESCRIPTION
@@ -89,6 +91,22 @@ This can be enabled by default with the configuration option mailinfo.scissors.
 --no-scissors::
 	Ignore scissors lines. Useful for overriding mailinfo.scissors settings.
 
+--quoted-cr=<action>::
+	Action when processes email messages sent with base64 or
+	quoted-printable encoding, and the decoded lines end with a CRLF
+	instead of a simple LF.
++
+The valid actions are:
++
+--
+*	`nowarn`: Git will do nothing when such a CRLF is found.
+*	`warn`: Git will issue a warning for each message if such a CRLF is
+	found.
+--
++
+The default action could be set by configuration option `mailinfo.quotedCR`.
+If no such configuration option has been set, `warn` will be used.
+
 <msg>::
 	The commit log message extracted from e-mail, usually
 	except the title line which comes from e-mail Subject.

builtin/mailinfo.c

@@ -38,6 +38,15 @@ static int parse_opt_explicit_encoding(const struct option *opt,
 	return 0;
 }
 
+static int parse_opt_quoted_cr(const struct option *opt, const char *arg, int unset)
+{
+	BUG_ON_OPT_NEG(unset);
+
+	if (mailinfo_parse_quoted_cr_action(arg, opt->value) != 0)
+		return error(_("bad action '%s' for '%s'"), arg, "--quoted-cr");
+	return 0;
+}
+
 int cmd_mailinfo(int argc, const char **argv, const char *prefix)
 {
 	struct metainfo_charset meta_charset;
@@ -61,6 +70,9 @@ int cmd_mailinfo(int argc, const char **argv, const char *prefix)
 			       N_("re-code metadata to this encoding"),
 			       PARSE_OPT_NONEG, parse_opt_explicit_encoding),
 		OPT_BOOL(0, "scissors", &mi.use_scissors, N_("use scissors")),
+		OPT_CALLBACK_F(0, "quoted-cr", &mi.quoted_cr, N_("<action>"),
+			       N_("action when quoted CR is found"),
+			       PARSE_OPT_NONEG, parse_opt_quoted_cr),
 		OPT_HIDDEN_BOOL(0, "inbody-headers", &mi.use_inbody_headers,
 			 N_("use headers in message's body")),
 		OPT_END()

mailinfo.c

@@ -1040,7 +1040,8 @@ static void handle_filter_flowed(struct mailinfo *mi, struct strbuf *line,
 
 static void summarize_quoted_cr(struct mailinfo *mi)
 {
-	if (mi->have_quoted_cr)
+	if (mi->have_quoted_cr &&
+	    mi->quoted_cr == quoted_cr_warn)
 		warning(_("quoted CRLF detected"));
 }
 
@@ -1220,6 +1221,17 @@ int mailinfo(struct mailinfo *mi, const char *msg, const char *patch)
 	return mi->input_error;
 }
 
+int mailinfo_parse_quoted_cr_action(const char *actionstr, int *action)
+{
+	if (!strcmp(actionstr, "nowarn"))
+		*action = quoted_cr_nowarn;
+	else if (!strcmp(actionstr, "warn"))
+		*action = quoted_cr_warn;
+	else
+		return -1;
+	return 0;
+}
+
 static int git_mailinfo_config(const char *var, const char *value, void *mi_)
 {
 	struct mailinfo *mi = mi_;
@@ -1230,6 +1242,11 @@ static int git_mailinfo_config(const char *var, const char *value, void *mi_)
 		mi->use_scissors = git_config_bool(var, value);
 		return 0;
 	}
+	if (!strcmp(var, "mailinfo.quotedcr")) {
+		if (mailinfo_parse_quoted_cr_action(value, &mi->quoted_cr) != 0)
+			return error(_("bad action '%s' for '%s'"), value, var);
+		return 0;
+	}
 	/* perhaps others here */
 	return 0;
 }
@@ -1242,6 +1259,7 @@ void setup_mailinfo(struct mailinfo *mi)
 	strbuf_init(&mi->charset, 0);
 	strbuf_init(&mi->log_message, 0);
 	strbuf_init(&mi->inbody_header_accum, 0);
+	mi->quoted_cr = quoted_cr_warn;
 	mi->header_stage = 1;
 	mi->use_inbody_headers = 1;
 	mi->content_top = mi->content;

mailinfo.h

@@ -5,6 +5,11 @@
 
 #define MAX_BOUNDARIES 5
 
+enum quoted_cr_action {
+	quoted_cr_nowarn,
+	quoted_cr_warn,
+};
+
 struct mailinfo {
 	FILE *input;
 	FILE *output;
@@ -14,6 +19,7 @@ struct mailinfo {
 	struct strbuf email;
 	int keep_subject;
 	int keep_non_patch_brackets_in_subject;
+	int quoted_cr; /* enum quoted_cr_action */
 	int add_message_id;
 	int use_scissors;
 	int use_inbody_headers;
@@ -40,6 +46,7 @@ struct mailinfo {
 	int input_error;
 };
 
+int mailinfo_parse_quoted_cr_action(const char *actionstr, int *action);
 void setup_mailinfo(struct mailinfo *);
 int mailinfo(struct mailinfo *, const char *msg, const char *patch);
 void clear_mailinfo(struct mailinfo *);

t/t5100-mailinfo.sh

@@ -255,7 +255,11 @@ test_expect_success 'mailinfo warn CR in base64 encoded email' '
 	check_quoted_cr_mail quoted-cr/0001 &&
 	test_must_be_empty quoted-cr/0001.err &&
 	check_quoted_cr_mail quoted-cr/0002 &&
-	grep "quoted CRLF detected" quoted-cr/0002.err
+	grep "quoted CRLF detected" quoted-cr/0002.err &&
+	check_quoted_cr_mail quoted-cr/0001 --quoted-cr=nowarn &&
+	test_must_be_empty quoted-cr/0001.err &&
+	check_quoted_cr_mail quoted-cr/0002 --quoted-cr=nowarn &&
+	test_must_be_empty quoted-cr/0002.err
 '
 
 test_done