macos_icons_hack() can be removed and replaced with a little locale configuration guide

[acc15]

Hello guys,

Stuck on this bug:

~ 1 year ago MacOS icon hack was added here #1711
But as you see it fixes only half of the problem (selections are still broken).

I've found a proper way how to solve all this nasty MacOS icon problems without using ANY dirty hacks.

Story

Some time ago Nerd icons Material Design icon set was moved to 0xf0000-0xf1af0 character range (https://github.com/ryanoasis/nerd-fonts/wiki/Glyph-Sets-and-Code-Points)

This completely screws ncurses and strange things starts to happen:

• O_NERD and O_EMOJI creates duplicate letters in filename #1692
• Nerd fonts cause misaligned columns in detail mode with names first #1802
• ...and many others icons related issues on Mac.

Locale definitions are located in /usr/share/locale dir.
Depending on user configuration some of this predefined locales is selected, and all locales ending with .UTF-8 has symlink for LC_CTYPE pointing to ../UTF-8/LC_CTYPE.
So character widths are baked into binary locale definition file: /usr/share/locale/UTF-8/LC_CTYPE.
UTF-8/LC_CTYPE file shipped with MacOS makes all characters in 0xf0000-0xf000e range to be 2 character wide.
Which is a root cause of all those MacOS icon issues.

I've checked ncurses code and he is relies solely on wcwidth calls (not wcswidth) to get character widths. wcwidth itself relies on LC_CTYPE locale category.

So to fix icon problems we need to create a proper LC_CTYPE file.

Locale building

To build correct UTF-8 LC_CTYPE on *BSD systems there is a tool called mklocale
And luckily OpenBSD project shares pretty good UTF-8 LC_CTYPE source file: https://github.com/openbsd/src/blob/master/share/locale/ctype/en_US.UTF-8.src

MacOS requires only a single modification to this file - ENCODING "UTF8" -> ENCODING "UTF-8" (additional dash).

After that this file can be converted to binary form using:

mklocale -o LC_CTYPE en_US.UTF-8.src  

Installation

There are many ways about how to install it.
According to setlocale Apple libc will look up next directories (in this order) for locale definition files:

 $PATH_LOCALE/locale/category
 /usr/share/locale/locale/category

Modification of /usr/share/locale requires SIP disabling (https://developer.apple.com/documentation/security/disabling_and_enabling_system_integrity_protection) and probably might break some system update in future, so its a bad way and generally should be avoided.

So to install:

1. sudo mkdir -p /usr/local/share/locale/UTF-8
2. sudo cp <path to binary LC_TYPE> /usr/local/share/locale/UTF-8
3. in ~/.zshrc add export PATH_LOCALE=/usr/local/share/locale and export LC_CTYPE=UTF-8

After this steps icons in nnn will just work without any hacks.

So i think macos_icon_hack() can be completely removed and replaced with this little guide about how to make a proper locale on MacOS.

What do u think?

[N-R-K]

Nice detailed analysis.

So i think macos_icon_hack() can be completely removed and replaced with this little guide about how to make a proper locale on MacOS.

This seems like a huge leap through.

a. This requires the user to go through some pretty convoluted steps to get icons working
b. The way you're exporting those vars in .zshrc will make this change affect other applications too, not just nnn.

Problem b can probably be solved by making a wrapper for nnn which sets up those env vars without exporting it for everything else. But problem a still remains, though.

[acc15]

a. What about script? https://github.com/acc15/macos_openbsd_utf8_locale/blob/master/macos_openbsd_utf8_locale.zsh
b. Yes, it will fix any other app which uses nerd material icons. Another options is an alias or wrapper script. But there is already - quitcd.

[N-R-K]

Yes, it will fix any other app which uses nerd material icons.

Shouldn't this issue (and workaround) be submitted to nerd icons repo then?