Incorrect XFontStruct entries in an XFontSet

[Andrey ``Bass'' Shcheglov]

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Hello,

I've encountered a problem of XFontSet "expansion" in libX11.

Consider the following C code:
<https://gist.github.com/unix-junkie/45674ced6c6aa06209677bbbaa2d655f>

In ru_RU.ISO-8859-5 locale,
- -monotype-arial-medium-r-normal--*-90-*-*-p-0-*-* font set is
correctly expanded to
- -monotype-arial-medium-r-normal--12-90-100-100-p-0-iso8859-5.

In ru_RU locale, however, the resulting XFontSet contains more entries
than actually necessary (corresponding to *all* encodings which
support Cyrillic):

> -monotype-arial-medium-r-normal--12-90-100-100-p-0-iso8859-1 
> -monotype-arial-medium-r-normal--12-90-100-100-p-0-koi8-r 
> -monotype-arial-medium-r-normal--12-90-100-100-p-0-microsoft-cp1251
>
> 
- -monotype-arial-medium-r-normal--12-90-100-100-p-0-iso8859-5
> -monotype-arial-medium-r-normal--12-90-100-100-p-0-iso10646-1

- -- despite the behaviour should be identical to that of
ru_RU.ISO-8859-5 (one should be thought of as an alias to the other).
The practical effect of this behaviour is that Motif, for instance,
refuses to draw a string at all (see this SO question for screenshots:
<https://stackoverflow.com/questions/37255098>).


I've run a research and found out different libX11 versions from
different vendors exhibit different behaviour in ru_RU locale (in
ru_RU.ISO-8859-5, they all behave correctly):


Solaris 8,
libX11 v6.4.1 (Xsun), ABI v4:
> *ok* (the font set is expanded to) 
> -monotype-arial-medium-r-normal--12-90-100-100-p-0-iso8859-5

Debian Woody (3.0) and Sarge (3.1),
libX11 v4.1.0-4.3.0 (XFree86), ABI v6.2.0:
> the font set is expanded to 
> -monotype-arial-medium-r-normal--12-90-100-100-p-0-koi8-r

Debian Etch (4.0),
libX11 v1.0.3 (X.org), ABI v6.2.0:
> *ok* (the font set is expanded to) 
> -monotype-arial-medium-r-normal--12-90-100-100-p-0-iso8859-5

Modern X11 versions (Debian Jessie (8.0) onwards, Gentoo Linux, Cygwin),
libX11 v1.6.2+ (X.org), ABI v6.3.0:
> the font set is expanded to 
> -monotype-arial-medium-r-normal--12-90-100-100-p-0-iso8859-1 
> -monotype-arial-medium-r-normal--12-90-100-100-p-0-koi8-r 
> -monotype-arial-medium-r-normal--12-90-100-100-p-0-microsoft-cp1251
>
> 
- -monotype-arial-medium-r-normal--12-90-100-100-p-0-iso8859-5
> -monotype-arial-medium-r-normal--12-90-100-100-p-0-iso10646-1


Questions:

- - Is this a known issue?
- - How can I further diagnose it? Have taken a look at libX11 source
code, but don't have a clue so far.
- - Where should I report a bug? Particularly, which bugzilla project
and component correspond to libX11?

Regards,
Andrey.


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