Re: NotoSansCJKjp-Regular cannot be loaded

[Masamichi Hosoda]

> Note: NotoSansJP-Regular and NotoSansCJKjp-Regular are similar
> but different fonts.

I've noticed that utf-8.ly confused the font names.

It requires the font `Noto Serif JP`.
https://gitlab.com/lilypond/lilypond/-/blob/d6b62def753b268fc5adfbe8443aa477d38395ef/input/regression/utf-8.ly#L30

And, it requires fonts-noto-cjk package for Debian/Ubuntu.
https://gitlab.com/lilypond/lilypond/-/blob/d6b62def753b268fc5adfbe8443aa477d38395ef/input/regression/utf-8.ly#L23

However, fonts-noto-cjk package contains `Noto Serif CJK JP`
instead of `Noto Serif JP`.
https://packages.debian.org/buster/fonts-noto-cjk

`Noto Serif CJK JP` and `Noto Serif JP` are similar but different fonts.
In other words, Debian/Ubuntu with fonts-noto-cjk package
does not have `Noto Serif JP` that utf-8.ly requires.

Then, I think fontconfig found NotoSansCJKjp-Regular
by searching for other fonts that can be used in Japanese
because the specified font is not available.

On the other hand, for Fedora,
utf-8.ly requires google-noto-serif-jp-fonts package.
https://gitlab.com/lilypond/lilypond/-/blob/d6b62def753b268fc5adfbe8443aa477d38395ef/input/regression/utf-8.ly#L18

It contains non-OTC version of exactly `Noto Serif JP`.
https://fedora.pkgs.org/33/fedora-x86_64/google-noto-serif-jp-fonts-20190416-7.fc33.noarch.rpm.html
Therefore, there is no problem.



There are many variations of the Noto font that can be used for Japanese.

* Region-specific Subset OpenType/CFF (Subset OTF)
    + Font name: Noto{Sans|Serif}JP-*
    + File name: Noto{Sans|Serif}JP-*.otf
* Language-specific OpenType/CFF (OTF)
    + Font name: Noto{Sans|Serif}CJKjp-*
    + File name: Noto{Sans|Serif}CJKjp-*.otf
* OpenType/CFF Collection (OTC)
    + Font name: Noto{Sans|Serif}CJKjp-* and non-Japanese font names
    + File name: Noto{Sans|Serif}CJK-*.ttc
* Super OpenType/CFF Collection (Super OTC)
    + Font name: Noto{Sans|Serif}CJKjp-* and non-Japanese font names
    + File name: Noto{Sans|Serif}CJK.ttc

Noto's OTF, OTC, and SuperOTC have the same font name, the same font content,
and only the file format is different.
Noto's Subset OTF is similar but different font names
and font content from the other fonts.