Please have a look at https://bugs.ghostscript.com/show_bug.cgi?id=708234
and the thread on the 'luatex' mailing list starting with https://tug.org/pipermail/luatex/2025-January/008035.html which discusses the problem that luatex creates invalid PDF outlines. While some PDF viewers like `evince` or `okular` are not affected, ghostscript (as a post-processor) and Acrobat (at least as a viewer) actually are. Luigi wrote to me the following in a private e-mail: > It's a bug in luatex, [...] Inside [the demo PDF] we have [stuff > like] > > ``` > 44848 0 obj > << /Names [ (Gregorian\040accidentals\040and\040key\040signatures) > [...] > ``` > > These strings are correct, but luatex sees '\','0','4','0' instead > of ' ' because this is the string that texinfo.tex encodes: > > ``` > % Escape PDF strings without converting > \begingroup > \directlua{ > function PDFescstr(str) > for c in string.bytes(str) do > if c <= 0x20 or c >= 0x80 or c == 0x28 or c == 0x29 or c == 0x5c then > tex.sprint(-2, > string.format(string.char(0x5c) .. string.char(0x25) .. '03o', > c)) > else > tex.sprint(-2, string.char(c)) > end > end > end > } > ``` > > So 0x20 is translated as '\\040', i.e., 4 bytes instead of ' ', > 1 byte, and strcmp correctly sorts 4 bytes and this is the bug: > luatex has to unscape these strings before the sorting. [...] > > is it necessary to escape the space 0x20? Perhaps no, so in the > lua function it could be c<0x20 instead of c<=0x20. This could be > an enhancement (and probably it masks the bug [...]) So: can this be fixed on the side of `texinfo.tex` at least for the space character, circumventing the luatex bug for the most common case? Luigi also writes: > Anyway, the pdf spec says that it's possible to use these escape > sequences: > > ``` > \n LINE FEED (0Ah) (LF) > \r CARRIAGE RETURN (0Dh) (CR) > \t HORIZONTAL TAB (09h) (HT) > \b BACKSPACE (08h) (BS) > \f FORM FEED (FF) > \( LEFT PARENTHESIS (28h) > \) RIGHT PARENTHESIS (29h) > \\ REVERSE SOLIDUS (5Ch) (Backslash) > ``` Using these escape sequences instead of the `\ddd` notation would avoid the bug for some other characters, too. Werner
