368550 - for quoted-printable msg new mail alert displays redundant 'equal sign' in the message preview field

Status: RESOLVED FIXED

(Thunderbird :: General, defect)

Description

[Karel Koubek]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.1) Gecko/20061204 Firefox/2.0.0.1
Build Identifier: version 2 beta 2 (20070128)

When I receive a message with some international characters (in my case: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable) the new mail alert which pops up shows a redundant equal sign in the message preview text field.

Notice: the equal symbol is right there in the message source at the end of the line, but doesn't show in thunderbird itself when I open the respective message.

Reproducible: Always

Steps to Reproduce:
1. Set the new mail alert to show all three fields (default)
2. Receive a plain-text (format=flowed) message, quoted-printable encoding, long enough
3. See the new mail alert, the message preview field
Actual Results:  
A redundant equal sign appears in the new mail alert (message preview field).

Expected Results:  
The alert message preview field should show text as in thunderbird's message window, with no extra garbage characters.

attachments follow.

Comment 1

[Karel Koubek]

Attachment: screenshot of a new mail alert

Comment 2

[Karel Koubek]

Attachment: problem message

Message which triggered the problem.

Comment 3

[Karel Koubek]

Just found that the same problem occurs in folder summary pop-up. 

Comment 4

[Magnus Melin [:mkmelin]]

I sent the below text to myself (as qp), didn't see the equal sign, but maybe the popup size/ font size happens to make it not show...

This is á test message, that illustrate the redundant equal sign in the alert pop-up.

Comment 5

[Karel Koubek]

OK, I concur that replicating this bug is fairly tricky. But when I receive messages in my native language it occurs quite often.
Another message example:

Some international character to trigger the proper encoding: á. Now just plain text without any symbols.

After receiving, the source looks like this:
Some international character to trigger the proper encoding: =E1. Now jus=
t=20
plain text without any symbols.

I'm no expert on the encoding used, but is it normal that some lines get truncated with the '=' symbol? Every time I manage to write an e-mail whose first line ends with '=' (in source), the problem with pop-up text occurs... 

Comment 6

[David :Bienvenu]

Maybe we're stripping line endings before doing the quoted printable decoding. I'll check.

Comment 7

[Karel Koubek]

Thank you very much!

P.S.: Keep up the great work! :-)

Comment 8

[David :Bienvenu]

we're doing the right thing with the line endings, I think, which is to leave them in before decoding the quoted printable text - but I suspect the quoted printable decoding code we have doesn't deal with line-endings (perhaps because previously it was only used by the search code, which doesn't really care about line endings or the stray extra '=' in the text.)

Comment 9

[David :Bienvenu]

Attachment: proposed fix

treat trailing = as a soft line break, i.e., ignore it, per http://en.wikipedia.org/wiki/Quoted-printable (see soft line breaks.)

Comment 10

[David :Bienvenu]

fixed on trunk and branch