From 24aee1b0291da4d6e27df247ee589974cb8f3a19 Mon Sep 17 00:00:00 2001
From: 132ikl <132@ikl.sh>
Date: Tue, 5 Nov 2024 03:39:08 -0500
Subject: [PATCH] Switch to unicase's to_folded_case (#14255)
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# Description
Switch `to_folded_case` to a proper case fold instead of
`str::to_lowercase` now that unicase exposes its `to_folded_case`
method.

Rel: #10884, https://github.com/seanmonstar/unicase/issues/61

# User-Facing Changes

Case insensitive sorts now do proper case folding.

Old behavior:

```nushell
[dreißig DREISSIG] | sort -i
# => ╭───┬──────────╮
# => │ 0 │ DREISSIG │
# => │ 1 │ dreißig  │
# => ╰───┴──────────╯
```

New behavior:

```nushell
[dreißig DREISSIG] | sort -i
# => ╭───┬──────────╮
# => │ 0 │ dreißig  │
# => │ 1 │ DREISSIG │
# => ╰───┴──────────╯
```
---
 crates/nu-utils/src/casing.rs | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/crates/nu-utils/src/casing.rs b/crates/nu-utils/src/casing.rs
index 6d22d6860b939..5ce15eacb5482 100644
--- a/crates/nu-utils/src/casing.rs
+++ b/crates/nu-utils/src/casing.rs
@@ -9,11 +9,6 @@ pub trait IgnoreCaseExt {
     /// language-invariant and consistent. Case folded text should be used
     /// solely for processing and generally should not be stored or displayed.
     ///
-    /// Note: this method might only do [`str::to_lowercase`] instead of a
-    /// full case fold, depending on how Nu is compiled. You should still
-    /// prefer using this method for generating case-insensitive strings,
-    /// though, as it expresses intent much better than `to_lowercase`.
-    ///
     /// [case folded]: <https://unicode.org/faq/casemap_charprop.html#2>
     fn to_folded_case(&self) -> String;
 
@@ -40,9 +35,7 @@ pub trait IgnoreCaseExt {
 
 impl IgnoreCaseExt for str {
     fn to_folded_case(&self) -> String {
-        // we only do to_lowercase, as unicase doesn't expose its case fold yet
-        // (seanmonstar/unicase#61) and we don't want to pull in another table
-        self.to_lowercase()
+        UniCase::new(self).to_folded_case()
     }
 
     fn eq_ignore_case(&self, other: &str) -> bool {