i18n: treat C locale as no grouping separator

src/uucore/src/lib/features/i18n/decimal.rs

@@ -6,7 +6,7 @@
 use std::sync::OnceLock;
 
 use icu_decimal::provider::DecimalSymbolsV1;
-use icu_locale::Locale;
+use icu_locale::{Locale, locale};
 use icu_provider::prelude::*;
 
 use crate::i18n::get_numeric_locale;
@@ -60,7 +60,15 @@ fn get_grouping_separator(loc: Locale) -> String {
 pub fn locale_grouping_separator() -> &'static str {
     static GROUPING_SEP: OnceLock<String> = OnceLock::new();
 
-    GROUPING_SEP.get_or_init(|| get_grouping_separator(get_numeric_locale().0.clone()))
+    GROUPING_SEP.get_or_init(|| {
+        let loc = get_numeric_locale().0.clone();
+        // C/POSIX locale (represented as "und") has no grouping separator.
+        if loc == locale!("und") {
+            String::new()
+        } else {
+            get_grouping_separator(loc)
+        }
+    })
 }
 
 #[cfg(test)]

tests/fixtures/sort/mixed_floats_ints_chars_numeric.expected

@@ -21,10 +21,10 @@ CARAvan
 8.013
 45
 46.89
-               4567.
-				37800
 576,446.88800000
 576,446.890
+               4567.
+				37800
 4798908.340000000000
 4798908.45
 4798908.8909800

tests/fixtures/sort/mixed_floats_ints_chars_numeric.expected.debug

@@ -67,18 +67,18 @@ __
 46.89
 _____
 _____
-               4567.
-               _____
-____________________
->>>>37800
-    _____
-_________
 576,446.88800000
 ___
 ________________
 576,446.890
 ___
 ___________
+               4567.
+               _____
+____________________
+>>>>37800
+    _____
+_________
 4798908.340000000000
 ____________________
 ____________________

tests/fixtures/sort/mixed_floats_ints_chars_numeric_stable.expected

@@ -24,10 +24,10 @@ CARAvan
 8.013
 45
 46.89
+576,446.890
+576,446.88800000
                4567.
 				37800
-576,446.88800000
-576,446.890
 4798908.340000000000
 4798908.45
 4798908.8909800

tests/fixtures/sort/mixed_floats_ints_chars_numeric_stable.expected.debug

@@ -50,14 +50,14 @@ _____
 __
 46.89
 _____
+576,446.890
+___
+576,446.88800000
+___
                4567.
                _____
 >>>>37800
     _____
-576,446.88800000
-___
-576,446.890
-___
 4798908.340000000000
 ____________________
 4798908.45

tests/fixtures/sort/mixed_floats_ints_chars_numeric_unique.expected

@@ -11,10 +11,9 @@
 8.013
 45
 46.89
+576,446.890
                4567.
 				37800
-576,446.88800000
-576,446.890
 4798908.340000000000
 4798908.45
 4798908.8909800

tests/fixtures/sort/mixed_floats_ints_chars_numeric_unique.expected.debug

@@ -24,14 +24,12 @@ _____
 __
 46.89
 _____
+576,446.890
+___
                4567.
                _____
 >>>>37800
     _____
-576,446.88800000
-___
-576,446.890
-___
 4798908.340000000000
 ____________________
 4798908.45

tests/fixtures/sort/mixed_floats_ints_chars_numeric_unique_reverse.expected

@@ -1,10 +1,9 @@
 4798908.8909800
 4798908.45
 4798908.340000000000
-576,446.890
-576,446.88800000
 				37800
                4567.
+576,446.890
 46.89
 45
 8.013

tests/fixtures/sort/mixed_floats_ints_chars_numeric_unique_reverse.expected.debug

@@ -4,14 +4,12 @@ _______________
 __________
 4798908.340000000000
 ____________________
-576,446.890
-___
-576,446.88800000
-___
 >>>>37800
     _____
                4567.
                _____
+576,446.890
+___
 46.89
 _____
 45

tests/fixtures/sort/multiple_groupings_numeric.expected

@@ -2,14 +2,14 @@
 
 
 CARAvan
+		1,999.99
+1,234
 	1.234
+			2,000
 2.000
 2.000,50
+12,34
 22
 23,.
 111
 	210
-1,234
-12,34
-		1,999.99
-			2,000

tests/fixtures/sort/multiple_groupings_numeric.expected.debug

@@ -10,15 +10,27 @@
 CARAvan
 ^ no match for key
 _______
+>>1,999.99
+  _
+__________
+1,234
+_
+_____
 >1.234
  _____
 ______
+>>>2,000
+   _
+________
 2.000
 _____
 _____
 2.000,50
 _____
 ________
+12,34
+__
+_____
 22
 __
 __
@@ -31,15 +43,3 @@ ___
 >210
  ___
 ____
-1,234
-_
-_____
-12,34
-__
-_____
->>1,999.99
-  _
-__________
->>>2,000
-   _
-________