1120979 - Left angle bracket introduced before content starting with 'From'

Status: RESOLVED DUPLICATE of bug 1134690

(Thunderbird :: Untriaged, defect)

Description

[Neville Hillyer]

User Agent: Mozilla/5.0 (Macintosh; PPC Mac OS X 10_5_8) AppleWebKit/537.77.4 (KHTML, like Gecko) Version/6.1.5 Safari/537.77.4

Steps to reproduce:

Sent myself a text email with content consisting of the word 'From' followed by a space followed by any character.

I am using TenFourBird 31.3.0 but have, so far, been unable to report this to them and would be grateful if anybody on this list could say if the bug originates from Thunderbird.


Actual results:

Received email, and email in Sent box, have a stray left angle bracket before content, eg:

<From x


Expected results:

From x

Comment 1

[Neville Hillyer]

I have just tried this on an Intel Mac with Thunderbird 31.3.0 and it does not exhibit my reported bug from which I assume it is related to TenFourBird and/or the installation on my PPC Mac.

The original test messages from TenFourBird show the extra left bracket on Thunderbird which appears to indicate that the bug is generated before the email is sent.

However I was surprised to see that my bug report email from BugZilla shows a stray right angle bracket before the last line which is not on the web site. 

Actual results:

<From - when this bug report was written this line started with a left bracket

Expected results:

From - when this bug report was written this line did not have any brackets

Comment 2

[rsx11m]

You can't have a "From " at the beginning of the first line of any plain-text part of the message body, this is a limitation of the mbox definition. To avoid that, a character is inserted at the first position of the first line of a paragraph, where the character itself can be anything.

Trying on the regular 31.4.0 release on Windows, this is a ' ' not a '<' and is removed when displaying the message. Thus, it may be something that TenFourBird is doing differently, but it would be a rather unmotivated change of the original code.

Comment 3

[Neville Hillyer]

(In reply to rsx11m from comment #2)

That is interesting.

I can see from further tests that the extra character gets added after line-feed for every occurrence of line-feed From space any-character but not lines which do not contain From etc. This can be seen in the source of drafts, sent and inbox.

As you say it appears that failure to remove the extra character is restricted to TenFourBird.

Can you explain the stray right angle bracket on incoming Bugzilla emails about this bug?

Comment 4

[rsx11m]

(In reply to Neville Hillyer from comment #1)
> Expected results:
> 
> From - when this bug report was written this line did not have any brackets

> Can you explain the stray right angle bracket on incoming Bugzilla emails about this bug?

In that example, you have an empty line before the "From " one, thus needs to be escaped. It's up to the application (bugzilla in this case) which may change it to ">From " (and that's actually what I've seen being used in the past rather frequently. I don't know if Thunderbird removes it (didn't get that specific notification mail), but it definitely does a " From " one.

Comment 5

[Neville Hillyer]

Attachment: nh.png

See my comments for a description of this image.

Comment 6

[Neville Hillyer]

(In reply to rsx11m from comment #4)

The more I read about mbox specifications the more confusing it gets.

RFC 4155 says it is not a specification and goes on to say, "The mbox database format is not documented in an authoritative specification, but instead exists as a well-known output format that is anecdotally documented, or which is only authoritatively documented for a specific platform or tool."

RFC 4155 refers to http://qmail.org/man/man5/mbox.html and is reasonable compatible with it except that qmail says, "The reader should not attempt to take advantage of the fact that every From_ line (past the beginning of the file) is preceded by a blank line."

I find it frustrating that there is not a clear distinction between quotes and 'From' escapes.

I have posted attachment nh.png showing 3 views of my original post here:

Top - my web browser view

Middle - my TenFourBird view of the Bugzilla email

Bottom - my Thunderbird view of the Bugzilla email

It appears that the Bugzilla email escaped the last 'From' and that neither TenFourBird nor Thunderbird removed the escape character. Is this a bug and if so where?

It is a pity that it is common to escape 'From' unnecessarily ie when it is not followed by the mandatory address and date.

I do wonder if ignoring address and date can result in an impossible decoding situation especially as it appears that any character can be used for 'From' escapes and there can be multiple escape levels - perhaps with different characters!.

Comment 7

[Thomas D. (:thomas8)]

Same as bug 1134690.
Might be dupe of an older bug.

I'm really not sure why they had to use something as common as "From" for demarcation of messages.

Comment 8

[Neville Hillyer]

(In reply to Thomas D. from comment #7)

RFC 4155 refers to http://qmail.org/man/man5/mbox.html which says:

"The From_ line always looks like From envsender date moreinfo. envsender is one word, without spaces or tabs; it is usually the envelope sender of the message. date is the delivery date of the message. It always contains exactly 24 characters in asctime format. moreinfo is optional; it may contain arbitrary information."

I can see no reason why a mail client should not look for "From" followed by 'envsender' followed by 'date' to detect the beginning of a message.