226175 - wrong cyrillic encoding if no russian characters in sending message

Status: RESOLVED DUPLICATE of bug 247958

(Thunderbird :: Message Compose Window, defect)

Description

[Aleksey Kirpichnikov]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.5) Gecko/20031007 Firebird/0.7
Build Identifier: Mozilla Thunderbird 0.4a (20031110)

When i send message without cyrillic characters in message body encoding of a
message became text/plain; charset=us-ascii; format=flowed instead text/plain;
charset=KOI8-R; format=flowed
If in a message body exist even one cyrillic character everything fine.
Message subject encoding doesn't affect this problem.
(I just add my signature with russian simbols it helps)

Reproducible: Always

Steps to Reproduce:
1. Start new message
2. in a message body write some english text

Actual Results:  
Message Content-type became text/plain; charset=us-ascii; format=flowed

Expected Results:  
Content-type: text/plain; charset=KOI8-R; format=flowed

This bug also appears in thunderbird 0.1, 0.2, 0.3

Comment 1

[Simon Montagu :smontagu]

This is by design, following RFC 2046:

   In general, composition software should always use the "lowest common
   denominator" character set possible.  For example, if a body contains
   only US-ASCII characters, it SHOULD be marked as being in the US-
   ASCII character set, not ISO-8859-1, which, like all the ISO-8859
   family of character sets, is a superset of US-ASCII.  More generally,
   if a widely-used character set is a subset of another character set,
   and a body contains only characters in the widely-used subset, it
   should be labelled as being in that subset.  This will increase the
   chances that the recipient will be able to view the resulting entity
   correctly.

But see bug 247958.

Comment 2

[Mike Cowperthwaite]

By default, TB and Mozilla now behave as desired in this bug.

*** This bug has been marked as a duplicate of 247958 ***