[luatex] What happens to glyphs not in the font?

[Arno Trautmann]

Taco Hoekwater wrote:
> Hi,
>
> On 25 Mar 2014, at 23:32, Arno Trautmann <Arno.Trautmann at gmx.de> wrote:
>
>> Martin Schröder wrote:
>>> 2014-03-25 22:12 GMT+01:00 Arno Trautmann <Arno.Trautmann at gmx.de>:
>>>> Martin Schröder wrote:
>>>>> I'd expect
>>>>> Missing character: There is no � in font cmr10!
>>>>> (maybe even with an "ß" :)
>>>>
>>>> Well – no. The minimal example I posted compiles just fine, neither a
>>>> warning or an error. (With an “eszett” in case it was broken by my mail
>>>> client?)
>>>
>>> Yes, but that's clearly a bug.
>>
>> oh … I thought it was a feature. Same happens with pdfTeX, btw.
>
> In pdftex you probably see nothing because it depends on the setting of
> \tracinglostchars.

Seems to be 1 in my case. As far as I understand the TeXbook, I would 
expect some record then?

> In luatex, there was a bug, where nothing was ever
> printed except in some odd cases inside math and the virtual font definition
> processing.
>
> I’ve committed a fix that checks during shipout and,  with \tracinglostchars=2,
> I now get this output on the terminal:
>
>    [1{/Users/taco/context/tex/texmf/fonts/map/pdftex/plain/pdftex.map}
>    Missing character: There is no ß (U+00DF) in font cmr10!
>    ]
>
> that is not completely perfectly right, because it is not really a character at
> that point, but that is mostly cosmetics, and this message is a bit easier to
> comprehend than ‘Missing glyph’.

That's nice. Thanks for explaining and fixing! (Although I'm not sure 
what exactly the best behaviour would be here …)

cheers
Arno