Re: badly calculated width of emoji in psql

On Fri, 2021-04-02 at 10:45 +0200, Pavel Stehule wrote:
> I am checked an query from https://www.depesz.com/2021/04/01/waiting-for-postgresql-14-add-unistr-function/ article.
>
> postgres=# SELECT U&'\+01F603';
> ┌──────────┐
> │ ?column? │
> ╞══════════╡
> │ 😃 │
> └──────────┘
> (1 row)
>
>
> The result is not correct. Emoji has width 2 chars, but psql calculates with just one char.

How about this:

diff --git a/src/common/wchar.c b/src/common/wchar.c
index 6e7d731e02..e2d0d9691c 100644
--- a/src/common/wchar.c
+++ b/src/common/wchar.c
@@ -673,7 +673,8 @@ ucs_wcwidth(pg_wchar ucs)
(ucs >= 0xfe30 && ucs <= 0xfe6f) || /* CJK Compatibility Forms */
(ucs >= 0xff00 && ucs <= 0xff5f) || /* Fullwidth Forms */
(ucs >= 0xffe0 && ucs <= 0xffe6) ||
- (ucs >= 0x20000 && ucs <= 0x2ffff)));
+ (ucs >= 0x20000 && ucs <= 0x2ffff) ||
+ (ucs >= 0x1f300 && ucs <= 0x1faff))); /* symbols and emojis */
}

/*

This is guesswork based on the unicode entries that look like symbols.

Yours,
Laurenz Albe