[PATCH v2 3/4] send-email: automatically determine transfer-encoding
- From
brian m. carlson <sandals@crustytoothpaste.net>
- Date
- Jul 8, 2018, 22:17 UTC
- Message-ID
- <20180708221713.518276-4-sandals@crustytoothpaste.net>
- In-Reply-To
- <20180708221713.518276-1-sandals@crustytoothpaste.net>
git send-email, when invoked without a --transfer-encoding option, sends 8bit data without a MIME version or a transfer encoding. This has several downsides.
First, unless the transfer encoding is specified, it defaults to 7bit, meaning that non-ASCII data isn't allowed. Second, if lines longer than 998 bytes are used, we will send an message that is invalid according to RFC 5322. The --validate option, which is the default, catches this issue, but it isn't clear to many people how to resolve this.
To solve these issues, default the transfer encoding to "auto", so that we explicitly specify 8bit encoding when lines don't exceed 998 bytes and quoted-printable otherwise. This means that we now always emit Content-Transfer-Encoding and MIME-Version headers, so remove the conditionals from this portion of the code.
It is unlikely that the unconditional inclusion of these two headers will affect the deliverability of messages in anything but a positive way, since MIME is already widespread and well understood by most email programs.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> --- Documentation/git-send-email.txt | 3 +-- git-send-email.perl | 18 ++++++------------ t/t9001-send-email.sh | 21 +++++++++++++++++++++ 3 files changed, 28 insertions(+), 14 deletions(-)
diff --git a/Documentation/git-send-email.txt b/Documentation/git-send-email.txt index 0e648075bb..2f32dbf16d 100644 --- a/Documentation/git-send-email.txt +++ b/Documentation/git-send-email.txt @@ -147,8 +147,7 @@ Note that no attempts whatsoever are made to validate the encoding. otherwise. + Default is the value of the `sendemail.transferEncoding` configuration -value; if that is unspecified, git will use 8bit and not add a -Content-Transfer-Encoding header. +value; if that is unspecified, default to `auto`. --xmailer:: --no-xmailer:: diff --git a/git-send-email.perl b/git-send-email.perl index e6bcc55827..f4c07908d2 100755 --- a/git-send-email.perl +++ b/git-send-email.perl @@ -231,7 +231,7 @@ sub do_edit { my (@suppress_cc); my ($auto_8bit_encoding); my ($compose_encoding); -my ($target_xfer_encoding); +my $target_xfer_encoding = 'auto'; my ($debug_net_smtp) = 0; # Net::SMTP, see send_message() @@ -1737,17 +1737,11 @@ sub process_file { } } } - if (defined $target_xfer_encoding) { - $xfer_encoding = '8bit' if not defined $xfer_encoding; - ($message, $xfer_encoding) = apply_transfer_encoding( - $message, $xfer_encoding, $target_xfer_encoding); - } - if (defined $xfer_encoding) { - push @xh, "Content-Transfer-Encoding: $xfer_encoding"; - } - if (defined $xfer_encoding or $has_content_type) { - unshift @xh, 'MIME-Version: 1.0' unless $has_mime_version; - } + $xfer_encoding = '8bit' if not defined $xfer_encoding; + ($message, $xfer_encoding) = apply_transfer_encoding( + $message, $xfer_encoding, $target_xfer_encoding); + push @xh, "Content-Transfer-Encoding: $xfer_encoding"; + unshift @xh, 'MIME-Version: 1.0' unless $has_mime_version; $needs_confirm = ( $confirm eq "always" or diff --git a/t/t9001-send-email.sh b/t/t9001-send-email.sh index 1b474cca28..1da282c415 100755 --- a/t/t9001-send-email.sh +++ b/t/t9001-send-email.sh @@ -225,6 +225,8 @@ X-Mailer: X-MAILER-STRING In-Reply-To: <unique-message-id@example.com> References: <unique-message-id@example.com> Reply-To: Reply <reply@example.com> +MIME-Version: 1.0 +Content-Transfer-Encoding: 8bit Result: OK EOF @@ -415,6 +417,7 @@ test_expect_success $PREREQ 'reject long lines' ' --from="Example <nobody@example.com>" \ --to=nobody@example.com \ --smtp-server="$(pwd)/fake.sendmail" \ + --transfer-encoding=8bit \ $patches longline.patch \ 2>errors && grep longline.patch errors @@ -609,6 +612,8 @@ Subject: [PATCH 1/1] Second. Date: DATE-STRING Message-Id: MESSAGE-ID-STRING X-Mailer: X-MAILER-STRING +MIME-Version: 1.0 +Content-Transfer-Encoding: 8bit Result: OK EOF @@ -653,6 +658,8 @@ Subject: [PATCH 1/1] Second. Date: DATE-STRING Message-Id: MESSAGE-ID-STRING X-Mailer: X-MAILER-STRING +MIME-Version: 1.0 +Content-Transfer-Encoding: 8bit Result: OK EOF @@ -688,6 +695,8 @@ Subject: [PATCH 1/1] Second. Date: DATE-STRING Message-Id: MESSAGE-ID-STRING X-Mailer: X-MAILER-STRING +MIME-Version: 1.0 +Content-Transfer-Encoding: 8bit Result: OK EOF @@ -714,6 +723,8 @@ Subject: [PATCH 1/1] Second. Date: DATE-STRING Message-Id: MESSAGE-ID-STRING X-Mailer: X-MAILER-STRING +MIME-Version: 1.0 +Content-Transfer-Encoding: 8bit Result: OK EOF @@ -748,6 +759,8 @@ Subject: [PATCH 1/1] Second. Date: DATE-STRING Message-Id: MESSAGE-ID-STRING X-Mailer: X-MAILER-STRING +MIME-Version: 1.0 +Content-Transfer-Encoding: 8bit Result: OK EOF @@ -779,6 +792,8 @@ Subject: [PATCH 1/1] Second. Date: DATE-STRING Message-Id: MESSAGE-ID-STRING X-Mailer: X-MAILER-STRING +MIME-Version: 1.0 +Content-Transfer-Encoding: 8bit Result: OK EOF @@ -810,6 +825,8 @@ Subject: [PATCH 1/1] Second. Date: DATE-STRING Message-Id: MESSAGE-ID-STRING X-Mailer: X-MAILER-STRING +MIME-Version: 1.0 +Content-Transfer-Encoding: 8bit Result: OK EOF @@ -845,6 +862,8 @@ Subject: [PATCH 1/1] Second. Date: DATE-STRING Message-Id: MESSAGE-ID-STRING X-Mailer: X-MAILER-STRING +MIME-Version: 1.0 +Content-Transfer-Encoding: 8bit Result: OK EOF @@ -873,6 +892,8 @@ Subject: [PATCH 1/1] Second. Date: DATE-STRING Message-Id: MESSAGE-ID-STRING X-Mailer: X-MAILER-STRING +MIME-Version: 1.0 +Content-Transfer-Encoding: 8bit Result: OK EOF