[ft-devel] assertion failure in cf2hints.c

[Derek B. Noonburg]

I've run across a font that causes an assertion failure at line 591 in
cf2hints.c:

    /* paired edges must be in proper order */
    FT_ASSERT( !isPair                                         ||
               topHintEdge->csCoord >= bottomHintEdge->csCoord );

I'm wondering: is there some reason this is an assertion, rather than an
error that gets reported back to the caller?  I.e., why doesn't it fall
into the same general category as any other sort of invalid/corrupted
font?

The font in question is embedded in a PDF file, which I received from a
customer who's doing fuzz testing.  The font is clearly bad, so I would
consider any sort of error return (refuse to load the font, refuse to
render the glyph, generate gibberish when rendering the glyph, etc.) to
be completely acceptable.

For now, the customer has turned off FreeType debugging, but I'm still
curious why this is an assertion.

I can extract the font and post it, if needed.

- Derek