ukify: don't attempt to print emoji

[dimich-dmb]

Fixes #35784

[bluca]

Why remove this? Sounds like a utf issue in your terminal?

[dimich-dmb]

Why remove this? Sounds like a utf issue in your terminal?

In my terminal I can see all UTF characters I need: Cyrillic, Greek, math, pseudographic, etc because I have installed corresponding fonts. To see emoji I need to find and install more fonts. I won't.
Moreover, Linux virtual console, for example, supports no more than 512 glyphs and they are limited in size.
Moreover, not all terminals are unicode-capable.

Unprintable characters in system utility output are confusing: it's hard to understand whether it is an important warning failed to print or just someone's joke.

[YHNdnzj]

Sorry, but we generally assume emojis just work if not on Linux VT and locale is in UTF-8 (see emoji_enabled()), hence dropping this wholly is not desirable. However, I think it's acceptable to teach ukify to honor $SYSTEMD_EMOJI like our C tools.

[dimich-dmb]

Sorry, but we generally assume emojis just work if not on Linux VT and locale is in UTF-8 (see emoji_enabled())

Sorry, but this assumption is wrong. Charmap "UTF-8" in locale doesn't mean that terminal is able to display any arbitrary unicode character.

However, I think it's acceptable to teach ukify to honor $SYSTEMD_EMOJI like our C tools.

I don't care how the issue will be fixed. I just proposed the simplest, and in my opinion, the most optimal solution.

[dimich-dmb]

Ah, I looked into C code and got your point now. I couldn't even imagine it has special code to display emojis 🤦 Fortunately I've never seen them in output of other systemd utilites. Of course, in this case removing garbage from warning message doesn't fit into overall style of this software. The PR can be closed.
However, the issue #35784 is still relevant: ukify displays ▯.