format-patch: teach --no-encode-email-headers

When commit subjects or authors have non-ASCII characters, git
format-patch Q-encodes them so they can be safely sent over email.
However, if the patch transfer method is something other than email (web
review tools, sneakernet), this only serves to make the patch metadata
harder to read without first applying it (unless you can decode RFC 2047
in your head). git am as well as some email software supports
non-Q-encoded mail as described in RFC 6531.

Add --[no-]encode-email-headers and format.encodeEmailHeaders to let the
user control this behavior.

Signed-off-by: Emma Brooks <me@pluvano.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 53 insertions, 0 deletions

diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index b653dd7d44..db7e733af9 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -1161,6 +1161,59 @@ test_expect_success 'format-patch wraps extremely long from-header (rfc2047)' '
 '
 
 cat >expect <<'EOF'
+From: Foö Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar
+ Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo
+ Bar Foo Bar Foo Bar Foo Bar <author@example.com>
+EOF
+test_expect_success 'format-patch wraps extremely long from-header (non-ASCII without Q-encoding)' '
+	echo content >>file &&
+	git add file &&
+	GIT_AUTHOR_NAME="Foö Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar" \
+	git commit -m author-check &&
+	git format-patch --no-encode-email-headers --stdout -1 >patch &&
+	sed -n "/^From: /p; /^ /p; /^$/q" patch >actual &&
+	test_cmp expect actual
+'
+
+cat >expect <<'EOF'
+Subject: [PATCH] Foö
+EOF
+test_expect_success 'subject lines are unencoded with --no-encode-email-headers' '
+	echo content >>file &&
+	git add file &&
+	git commit -m "Foö" &&
+	git format-patch --no-encode-email-headers -1 --stdout >patch &&
+	grep ^Subject: patch >actual &&
+	test_cmp expect actual
+'
+
+cat >expect <<'EOF'
+Subject: [PATCH] Foö
+EOF
+test_expect_success 'subject lines are unencoded with format.encodeEmailHeaders=false' '
+	echo content >>file &&
+	git add file &&
+	git commit -m "Foö" &&
+	git config format.encodeEmailHeaders false &&
+	git format-patch -1 --stdout >patch &&
+	grep ^Subject: patch >actual &&
+	test_cmp expect actual
+'
+
+cat >expect <<'EOF'
+Subject: [PATCH] =?UTF-8?q?Fo=C3=B6?=
+EOF
+test_expect_success '--encode-email-headers overrides format.encodeEmailHeaders' '
+	echo content >>file &&
+	git add file &&
+	git commit -m "Foö" &&
+	git config format.encodeEmailHeaders false &&
+	git format-patch --encode-email-headers -1 --stdout >patch &&
+	grep ^Subject: patch >actual &&
+	test_cmp expect actual
+'
+
+cat >expect <<'EOF'
 Subject: header with . in it
 EOF
 test_expect_success 'subject lines do not have 822 atom-quoting' '