Bypassing the LastResort font error

As I noted previously, my mini web browser Cobro had begun occasionally dumping flurries of a message Python[6570:d07] Critical failure: the LastResort font is unavailable. I found that it is refers to a need to find a font literally named LastResort.ttf that Apple distributes. This font contains a category glyph for every valid Unicode character, so a reasonable "missing character" glyph can be displayed when the active font lacks one.

Apparently the web browser cannot access this font, even though it is present in /System/Library/Fonts. I haven't found out why. Also it doesn't appear in the list of font families you can fetch from the Qt font database (see previous post); and it doesn't appear in the list of fonts presented by the very useful PopChar product, nor in the list presented by PhotoShop's Text tool. So there's a conspiracy here to hide its name. Is the conspiracy at the Mac OS level? Probably, but I don't know.

I wanted a reliable failure example, but I walked back through the last half-dozen comic pages for every comic I browse, and none triggered the message. Rats! OK, what else?

Thinking about it, the problem can only occur if the default font lacks some Unicode glyph. US-based comics are unlikely to stray outside the Latin-1 set. I look at only a few Europe-based comics and even they haven't much reason to use non-Latin-1 letters except possibly the Euro symbol. Perhaps there was some ad copy that had a Euro sign, or an n-acute or -tilde, or a brand name in Cyrillic, and that ad isn't currently being included. But most fonts these days have at least the Latin-1 extended-A and the Greek and Cyrillic blocks covered. So why would the Webkit default font not have...

Oh, wait.

A couple weeks ago, I changed the list-of-comics widget to display in Comic Sans. You know, because it would be cute for a comic browser to list comic names in... And I think maybe...

Yurp. I also put in a couple of lines in the initialization of the QWebPage to set its default sans-serif font to the same Comic Sans. I even left in a comment "#Needed? Desirable?" Could this be a problem?

Actually, no, it shouldn't be. Checking the repertoire with Font Book I see that what I have on this machine, "Comic Sans MS", has a fairly complete set of glyphs including Cyrillic and a Euro, certainly everything that an ad might call upon.

Nevertheless, I took that out, letting the web page display default to whatever font it wants (it appears to be Times Roman), and now I just have to wait a while and see if the Last Resort message pops up again.

Later: It hasn't.