1664993 - multipart/alterantive does not show ics + message body

Status: RESOLVED DUPLICATE of bug 760412

(Calendar :: E-mail based Scheduling (iTIP/iMIP), defect)

Description

[Daniel AJ Sokolov]

User Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.83 Safari/537.36

Steps to reproduce:

Received multi-part emails with attachments. That works fine, when all attachments are defined at the beginning of the email, for example like this:

Content-Type: multipart/mixed; boundary="006_459d2e07d5cb44e584d2c82fa79673b9fffffffffffffff"
Content-Language: en-US
X-Scanned-By: MIMEDefang 2.84

This is a multi-part message in MIME format.

--006_459d2e07d5cb44e584d2c82fa79673b9fffffffffffffff
Content-Type: multipart/related; type="multipart/alternative"; boundary="005_459d2e07d5cb44e584d2c82fa79673b9fffffffffffffff"

--005_459d2e07d5cb44e584d2c82fa79673b9fffffffffffffff
Content-Type: multipart/alternative; boundary="000_459d2e07d5cb44e584d2c82fa79673b9fffffffffffffff"

--000_459d2e07d5cb44e584d2c82fa79673b9fffffffffffffff
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable

$HereIsTheMessageText

HOWEVER, it does NOT work, when only the first part of the Multi-Part message is defined at the beginning, and the further parts are only defined immediately before the relevant part begins. In that case, Thunderbird ignores all but the first part. Example:

Content-Type: multipart/alternative; boundary="000_5241ba68090e423494e2eaf24683e56ffffffffffffffff"
Content-Language: en-US
X-Scanned-By: MIMEDefang 2.84

This is a multi-part message in MIME format.

--000_5241ba68090e423494e2eaf24683e56ffffffffffffffff
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable

$HereIsMessageText

--000_5241ba68090e423494e2eaf24683e56ffffffffffffffff
Content-Type: text/html; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable

$HereIsHTMLCode

--000_5241ba68090e423494e2eaf24683e56ffffffffffffffff
Content-Type: text/calendar; method="REQUEST"; charset="utf-8"
Content-Transfer-Encoding: base64

$HereIsBASE64Code

--000_5241ba68090e423494e2eaf24683e56ffffffffffffffff

In that example, the HTML part and the Base64 encoded attachment are completeley ignored.

That structure is common with emails generated by MS Exchange Server Calendars.

Actual results:

When the content-type is not defined for all parts of a Multi-Part message right at the beginning of the message, but is defined immediately at the start of each message part, only the very first message part is parsed. Thunderbird ignores all following massage parts. Thus, there is no indication of additional message parts being included in the message, attachments can't be accessed or downloaded.

Expected results:

Thunderbird should parse all attachments, indicate their presence and make them available for download.