am: learn to process quoted lines that ends with CRLF

In previous changes, mailinfo has learnt to process lines that decoded
from base64 or quoted-printable, and ends with CRLF.

Let's teach "am" that new trick, too.

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

Documentation/git-am.txt

@@ -15,6 +15,7 @@ SYNOPSIS
 	 [--whitespace=<option>] [-C<n>] [-p<n>] [--directory=<dir>]
 	 [--exclude=<path>] [--include=<path>] [--reject] [-q | --quiet]
 	 [--[no-]scissors] [-S[<keyid>]] [--patch-format=<format>]
+	 [--quoted-cr=<action>]
 	 [(<mbox> | <Maildir>)...]
 'git am' (--continue | --skip | --abort | --quit | --show-current-patch[=(diff|raw)])
 
@@ -59,6 +60,9 @@ OPTIONS
 --no-scissors::
 	Ignore scissors lines (see linkgit:git-mailinfo[1]).
 
+--quoted-cr=<action>::
+	This flag will be passed down to 'git mailinfo' (see linkgit:git-mailinfo[1]).
+
 -m::
 --message-id::
 	Pass the `-m` flag to 'git mailinfo' (see linkgit:git-mailinfo[1]),

builtin/am.c

@@ -116,6 +116,7 @@ struct am_state {
 	int keep; /* enum keep_type */
 	int message_id;
 	int scissors; /* enum scissors_type */
+	int quoted_cr; /* enum quoted_cr_action */
 	struct strvec git_apply_opts;
 	const char *resolvemsg;
 	int committer_date_is_author_date;
@@ -145,6 +146,7 @@ static void am_state_init(struct am_state *state)
 	git_config_get_bool("am.messageid", &state->message_id);
 
 	state->scissors = SCISSORS_UNSET;
+	state->quoted_cr = quoted_cr_unset;
 
 	strvec_init(&state->git_apply_opts);
 
@@ -165,6 +167,16 @@ static void am_state_release(struct am_state *state)
 	strvec_clear(&state->git_apply_opts);
 }
 
+static int am_option_parse_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;
+}
+
 /**
  * Returns path relative to the am_state directory.
  */
@@ -397,6 +409,12 @@ static void am_load(struct am_state *state)
 	else
 		state->scissors = SCISSORS_UNSET;
 
+	read_state_file(&sb, state, "quoted-cr", 1);
+	if (!*sb.buf)
+		state->quoted_cr = quoted_cr_unset;
+	else if (mailinfo_parse_quoted_cr_action(sb.buf, &state->quoted_cr) != 0)
+		die(_("could not parse %s"), am_path(state, "quoted-cr"));
+
 	read_state_file(&sb, state, "apply-opt", 1);
 	strvec_clear(&state->git_apply_opts);
 	if (sq_dequote_to_strvec(sb.buf, &state->git_apply_opts) < 0)
@@ -1002,6 +1020,24 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 	}
 	write_state_text(state, "scissors", str);
 
+	switch (state->quoted_cr) {
+	case quoted_cr_unset:
+		str = "";
+		break;
+	case quoted_cr_nowarn:
+		str = "nowarn";
+		break;
+	case quoted_cr_warn:
+		str = "warn";
+		break;
+	case quoted_cr_strip:
+		str = "strip";
+		break;
+	default:
+		BUG("invalid value for state->quoted_cr");
+	}
+	write_state_text(state, "quoted-cr", str);
+
 	sq_quote_argv(&sb, state->git_apply_opts.v);
 	write_state_text(state, "apply-opt", sb.buf);
 
@@ -1162,6 +1198,18 @@ static int parse_mail(struct am_state *state, const char *mail)
 		BUG("invalid value for state->scissors");
 	}
 
+	switch (state->quoted_cr) {
+	case quoted_cr_unset:
+		break;
+	case quoted_cr_nowarn:
+	case quoted_cr_warn:
+	case quoted_cr_strip:
+		mi.quoted_cr = state->quoted_cr;
+		break;
+	default:
+		BUG("invalid value for state->quoted_cr");
+	}
+
 	mi.input = xfopen(mail, "r");
 	mi.output = xfopen(am_path(state, "info"), "w");
 	if (mailinfo(&mi, am_path(state, "msg"), am_path(state, "patch")))
@@ -2242,6 +2290,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 			0, PARSE_OPT_NONEG),
 		OPT_BOOL('c', "scissors", &state.scissors,
 			N_("strip everything before a scissors line")),
+		OPT_CALLBACK_F(0, "quoted-cr", &state.quoted_cr, N_("action"),
+			       N_("pass it through git-mailinfo"),
+			       PARSE_OPT_NONEG, am_option_parse_quoted_cr),
 		OPT_PASSTHRU_ARGV(0, "whitespace", &state.git_apply_opts, N_("action"),
 			N_("pass it through git-apply"),
 			0),

contrib/completion/git-completion.bash

@@ -1333,6 +1333,7 @@ __git_whitespacelist="nowarn warn error error-all fix"
 __git_patchformat="mbox stgit stgit-series hg mboxrd"
 __git_showcurrentpatch="diff raw"
 __git_am_inprogress_options="--skip --continue --resolved --abort --quit --show-current-patch"
+__git_quoted_cr="nowarn warn strip"
 
 _git_am ()
 {
@@ -1354,6 +1355,10 @@ _git_am ()
 		__gitcomp "$__git_showcurrentpatch" "" "${cur##--show-current-patch=}"
 		return
 		;;
+	--quoted-cr=*)
+		__gitcomp "$__git_quoted_cr" "" "${cur##--quoted-cr=}"
+		return
+		;;
 	--*)
 		__gitcomp_builtin am "" \
 			"$__git_am_inprogress_options"

mailinfo.h

@@ -6,6 +6,7 @@
 #define MAX_BOUNDARIES 5
 
 enum quoted_cr_action {
+	quoted_cr_unset = -1,
 	quoted_cr_nowarn,
 	quoted_cr_warn,
 	quoted_cr_strip,

t/t4258-am-quoted-cr.sh

@@ -0,0 +1,37 @@
+#!/bin/sh
+
+test_description='test am --quoted-cr=<action>'
+
+. ./test-lib.sh
+
+DATA="$TEST_DIRECTORY/t4258"
+
+test_expect_success 'setup' '
+	test_write_lines one two three >text &&
+	test_commit one text &&
+	test_write_lines one owt three >text &&
+	test_commit two text
+'
+
+test_expect_success 'am warn if quoted-cr is found' '
+	git reset --hard one &&
+	test_must_fail git am "$DATA/mbox" 2>err &&
+	grep "quoted CRLF detected" err
+'
+
+test_expect_success 'am --quoted-cr=strip' '
+	test_might_fail git am --abort &&
+	git reset --hard one &&
+	git am --quoted-cr=strip "$DATA/mbox" &&
+	git diff --exit-code HEAD two
+'
+
+test_expect_success 'am with config mailinfo.quotecr=strip' '
+	test_might_fail git am --abort &&
+	git reset --hard one &&
+	test_config mailinfo.quotedCr strip &&
+	git am "$DATA/mbox" &&
+	git diff --exit-code HEAD two
+'
+
+test_done

t/t4258/mbox

@@ -0,0 +1,12 @@
+From: A U Thor <mail@example.com>
+To: list@example.org
+Subject: [PATCH v2] sample
+Date: Mon,  3 Aug 2020 22:40:55 +0700
+Message-Id: <msg-id@example.com>
+Content-Type: text/plain; charset="utf-8"
+Content-Transfer-Encoding: base64
+
+VGhpcyBpcyBjb21taXQgbWVzc2FnZS4NCi0tLQ0KIHRleHQgfCAyICstDQogMSBmaWxlIGNoYW5n
+ZWQsIDEgaW5zZXJ0aW9uKCspLCAxIGRlbGV0aW9uKC0pDQoNCmRpZmYgLS1naXQgYS90ZXh0IGIv
+dGV4dA0KaW5kZXggNTYyNmFiZi4uZjcxOWVmZCAxMDA2NDQNCi0tLSBhL3RleHQNCisrKyBiL3Rl
+eHQNCkBAIC0xICsxIEBADQotb25lDQordHdvDQotLSANCjIuMzEuMQoK