Determine Turkish casing from the locale name instead of collation#132002

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Determine Turkish casing from the locale name instead of collation #132002

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4dc24c7
Determine Turkish casing from the locale name instead of collation
MsfPablo Aug 7, 2026
6d3b84d
Enable the Turkish casing TextInfo cases on Android
MsfPablo Aug 7, 2026
7a2a403
Fix ASCII casing fast path bypassing Turkish dispatch on Android
MsfPablo Aug 11, 2026
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15 changes: 14 additions & 1 deletion src/libraries/System.Private.CoreLib/src/System/Globalization/TextInfo.Icu.cs
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -14,7 +14,20 @@ private static bool NeedsTurkishCasing(string localeName)
{
Debug.Assert(localeName != null);

return CultureInfo.GetCultureInfo(localeName).CompareInfo.Compare("\u0131", "I", CompareOptions.IgnoreCase) == 0;
// ICU applies the Turkish dotted/dotless "i" casing rules to the "tr" and "az"
// languages. This is determined from the locale name rather than by probing the
// collation tailoring, because some platforms (notably Android, which uses the
// system ICU) do not ship the collation data that probe relies on, which would
// silently fall back to non-Turkish casing.
ReadOnlySpan<char> language = localeName.AsSpan();
int separatorIndex = language.IndexOfAny('-', '_');
if (separatorIndex >= 0)
{
language = language.Slice(0, separatorIndex);
}

return language.Equals("tr", StringComparison.OrdinalIgnoreCase) ||
language.Equals("az", StringComparison.OrdinalIgnoreCase);
}

internal unsafe void IcuChangeCase(char* src, int srcLen, char* dstBuffer, int dstBufferCapacity, bool bToUpper)
Expand Down
27 changes: 27 additions & 0 deletions src/libraries/System.Private.CoreLib/src/System/Globalization/TextInfo.cs
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Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -579,10 +579,37 @@ private bool IsAsciiCasingSameAsInvariant
[MethodImpl(MethodImplOptions.NoInlining)]
private void PopulateIsAsciiCasingSameAsInvariant()
{
// Turkish (tr / tr-*) and Azerbaijani (az / az-*) cultures have an ASCII
// casing relationship that differs from invariant (e.g. U+0049 ↔ U+0131,
// U+0069 ↔ U+0130). The CompareInfo.Compare probe below is unreliable on
// platforms whose collation data is incomplete (notably the system ICU
// on Android), where it can incorrectly report the two alphabets as
// case-equal. Derive the answer from the locale name for those
// languages instead, the same way IcuChangeCase decides whether to
// dispatch through the Turkish PAL.
if (IsLocaleWithNonInvariantAsciiCasing(_textInfoName))
{
_isAsciiCasingSameAsInvariant = NullableBool.False;
return;
}

bool compareResult = CultureInfo.GetCultureInfo(_textInfoName).CompareInfo.Compare("abcdefghijklmnopqrstuvwxyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZ", CompareOptions.IgnoreCase) == 0;
_isAsciiCasingSameAsInvariant = compareResult ? NullableBool.True : NullableBool.False;
}

private static bool IsLocaleWithNonInvariantAsciiCasing(string localeName)
{
ReadOnlySpan<char> language = localeName.AsSpan();
int separatorIndex = language.IndexOfAny('-', '_');
if (separatorIndex >= 0)
{
language = language.Slice(0, separatorIndex);
}

return language.Equals("tr", StringComparison.OrdinalIgnoreCase) ||
language.Equals("az", StringComparison.OrdinalIgnoreCase);
}

/// <summary>
/// Returns true if the dominant direction of text and UI such as the
/// relative position of buttons and scroll bars
Expand Down
22 changes: 7 additions & 15 deletions ...ies/System.Runtime/tests/System.Globalization.Tests/System/Globalization/TextInfoTests.cs
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -280,21 +280,17 @@ public static IEnumerable<object[]> ToLower_TestData()

foreach (string cultureName in GetTestLocales())
{
// Android has its own ICU, which doesn't work well with tr
if (!PlatformDetection.IsAndroid && !PlatformDetection.IsLinuxBionic)
{
yield return new object[] { cultureName, "I", "\u0131" };
yield return new object[] { cultureName, "HI!", "h\u0131!" };
yield return new object[] { cultureName, "HI\n\0H\u0130\t!", "h\u0131\n\0hi\u0009!" };
}
yield return new object[] { cultureName, "I", "\u0131" };
yield return new object[] { cultureName, "HI!", "h\u0131!" };
yield return new object[] { cultureName, "HI\n\0H\u0130\t!", "h\u0131\n\0hi\u0009!" };
yield return new object[] { cultureName, "\u0130", "i" };
yield return new object[] { cultureName, "i", "i" };

}

// ICU has special tailoring for the en-US-POSIX locale which treats "i" and "I" as different letters
// instead of two letters with a case difference during collation. Make sure this doesn't confuse our
// casing implementation, which uses collation to understand if we need to do Turkish casing or not.
// casing implementation, which must apply Turkish casing only for the tr and az languages.
if (!PlatformDetection.IsWindows && PlatformDetection.IsNotBrowser)
{
yield return new object[] { "en-US-POSIX", "I", "i" };
Expand DownExpand Up@@ -431,20 +427,16 @@ public static IEnumerable<object[]> ToUpper_TestData()
// Turkish i
foreach (string cultureName in GetTestLocales())
{
// Android has its own ICU, which doesn't work well with tr
if (!PlatformDetection.IsAndroid && !PlatformDetection.IsLinuxBionic)
{
yield return new object[] { cultureName, "i", "\u0130" };
yield return new object[] { cultureName, "H\u0131\n\0Hi\u0009!", "HI\n\0H\u0130\t!" };
}
yield return new object[] { cultureName, "i", "\u0130" };
yield return new object[] { cultureName, "H\u0131\n\0Hi\u0009!", "HI\n\0H\u0130\t!" };
yield return new object[] { cultureName, "\u0130", "\u0130" };
yield return new object[] { cultureName, "\u0131", "I" };
yield return new object[] { cultureName, "I", "I" };
}

// ICU has special tailoring for the en-US-POSIX locale which treats "i" and "I" as different letters
// instead of two letters with a case difference during collation. Make sure this doesn't confuse our
// casing implementation, which uses collation to understand if we need to do Turkish casing or not.
// casing implementation, which must apply Turkish casing only for the tr and az languages.
if (!PlatformDetection.IsWindows && PlatformDetection.IsNotBrowser)
{
yield return new object[] { "en-US-POSIX", "i", "I" };
Expand Down
Loading
, 'i'); if (__m === '*' || __re.test(location.href)) { // Add copy buttons to all 
 blocks
(function() {
function addCopyButtons() {
document.querySelectorAll('pre code').forEach(function(codeBlock) {
if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;
codeBlock.parentElement.setAttribute('data-copy-added', 'true');
var btn = document.createElement('button');
btn.textContent = 'Copy';
btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';
btn.onmouseover = function() { this.style.opacity = '1'; };
btn.onmouseout = function() { this.style.opacity = '0.7'; };
btn.onclick = function() {
navigator.clipboard.writeText(codeBlock.textContent).then(function() {
btn.textContent = 'Copied!';
setTimeout(function() { btn.textContent = 'Copy'; }, 1500);
});
};
codeBlock.parentElement.style.position = 'relative';
codeBlock.parentElement.appendChild(btn);
});
}
addCopyButtons();
// Re-run on dynamic content
var observer = new MutationObserver(addCopyButtons);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

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Determine Turkish casing from the locale name instead of collation#132002

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Determine Turkish casing from the locale name instead of collation
#132002
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4dc24c7

Determine Turkish casing from the locale name instead of collation


MsfPablo Aug 7, 2026
6d3b84d

Enable the Turkish casing TextInfo cases on Android


MsfPablo Aug 7, 2026
7a2a403

Fix ASCII casing fast path bypassing Turkish dispatch on Android


MsfPablo Aug 11, 2026

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15 changes: 14 additions & 1 deletion
src/libraries/System.Private.CoreLib/src/System/Globalization/TextInfo.Icu.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -14,7 +14,20 @@ private static bool NeedsTurkishCasing(string localeName)
 {
 Debug.Assert(localeName != null);

 return CultureInfo.GetCultureInfo(localeName).CompareInfo.Compare("\u0131", "I", CompareOptions.IgnoreCase) == 0;
 // ICU applies the Turkish dotted/dotless "i" casing rules to the "tr" and "az"
 // languages. This is determined from the locale name rather than by probing the
 // collation tailoring, because some platforms (notably Android, which uses the
 // system ICU) do not ship the collation data that probe relies on, which would
 // silently fall back to non-Turkish casing.
 ReadOnlySpan<char> language = localeName.AsSpan();
 int separatorIndex = language.IndexOfAny('-', '_');
 if (separatorIndex >= 0)
 {
 language = language.Slice(0, separatorIndex);
 }

 return language.Equals("tr", StringComparison.OrdinalIgnoreCase) ||
 language.Equals("az", StringComparison.OrdinalIgnoreCase);
 }

 internal unsafe void IcuChangeCase(char* src, int srcLen, char* dstBuffer, int dstBufferCapacity, bool bToUpper)
Expand Down

27 changes: 27 additions & 0 deletions
src/libraries/System.Private.CoreLib/src/System/Globalization/TextInfo.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -579,10 +579,37 @@ private bool IsAsciiCasingSameAsInvariant
 [MethodImpl(MethodImplOptions.NoInlining)]
 private void PopulateIsAsciiCasingSameAsInvariant()
 {
 // Turkish (tr / tr-*) and Azerbaijani (az / az-*) cultures have an ASCII
 // casing relationship that differs from invariant (e.g. U+0049 ↔ U+0131,
 // U+0069 ↔ U+0130). The CompareInfo.Compare probe below is unreliable on
 // platforms whose collation data is incomplete (notably the system ICU
 // on Android), where it can incorrectly report the two alphabets as
 // case-equal. Derive the answer from the locale name for those
 // languages instead, the same way IcuChangeCase decides whether to
 // dispatch through the Turkish PAL.
 if (IsLocaleWithNonInvariantAsciiCasing(_textInfoName))
 {
 _isAsciiCasingSameAsInvariant = NullableBool.False;
 return;
 }

 bool compareResult = CultureInfo.GetCultureInfo(_textInfoName).CompareInfo.Compare("abcdefghijklmnopqrstuvwxyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZ", CompareOptions.IgnoreCase) == 0;
 _isAsciiCasingSameAsInvariant = compareResult ? NullableBool.True : NullableBool.False;
 }

 private static bool IsLocaleWithNonInvariantAsciiCasing(string localeName)
 {
 ReadOnlySpan<char> language = localeName.AsSpan();
 int separatorIndex = language.IndexOfAny('-', '_');
 if (separatorIndex >= 0)
 {
 language = language.Slice(0, separatorIndex);
 }

 return language.Equals("tr", StringComparison.OrdinalIgnoreCase) ||
 language.Equals("az", StringComparison.OrdinalIgnoreCase);
 }

 /// <summary>
 /// Returns true if the dominant direction of text and UI such as the
 /// relative position of buttons and scroll bars
Expand Down

22 changes: 7 additions & 15 deletions
...ies/System.Runtime/tests/System.Globalization.Tests/System/Globalization/TextInfoTests.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -280,21 +280,17 @@ public static IEnumerable<object[]> ToLower_TestData()

 foreach (string cultureName in GetTestLocales())
 {
 // Android has its own ICU, which doesn't work well with tr
 if (!PlatformDetection.IsAndroid && !PlatformDetection.IsLinuxBionic)
 {
 yield return new object[] { cultureName, "I", "\u0131" };
 yield return new object[] { cultureName, "HI!", "h\u0131!" };
 yield return new object[] { cultureName, "HI\n\0H\u0130\t!", "h\u0131\n\0hi\u0009!" };
 }
 yield return new object[] { cultureName, "I", "\u0131" };
 yield return new object[] { cultureName, "HI!", "h\u0131!" };
 yield return new object[] { cultureName, "HI\n\0H\u0130\t!", "h\u0131\n\0hi\u0009!" };
 yield return new object[] { cultureName, "\u0130", "i" };
 yield return new object[] { cultureName, "i", "i" };

 }

 // ICU has special tailoring for the en-US-POSIX locale which treats "i" and "I" as different letters
 // instead of two letters with a case difference during collation. Make sure this doesn't confuse our
 // casing implementation, which uses collation to understand if we need to do Turkish casing or not.
 // casing implementation, which must apply Turkish casing only for the tr and az languages.
 if (!PlatformDetection.IsWindows && PlatformDetection.IsNotBrowser)
 {
 yield return new object[] { "en-US-POSIX", "I", "i" };
Expand DownExpand Up@@ -431,20 +427,16 @@ public static IEnumerable<object[]> ToUpper_TestData()
 // Turkish i
 foreach (string cultureName in GetTestLocales())
 {
 // Android has its own ICU, which doesn't work well with tr
 if (!PlatformDetection.IsAndroid && !PlatformDetection.IsLinuxBionic)
 {
 yield return new object[] { cultureName, "i", "\u0130" };
 yield return new object[] { cultureName, "H\u0131\n\0Hi\u0009!", "HI\n\0H\u0130\t!" };
 }
 yield return new object[] { cultureName, "i", "\u0130" };
 yield return new object[] { cultureName, "H\u0131\n\0Hi\u0009!", "HI\n\0H\u0130\t!" };
 yield return new object[] { cultureName, "\u0130", "\u0130" };
 yield return new object[] { cultureName, "\u0131", "I" };
 yield return new object[] { cultureName, "I", "I" };
 }

 // ICU has special tailoring for the en-US-POSIX locale which treats "i" and "I" as different letters
 // instead of two letters with a case difference during collation. Make sure this doesn't confuse our
 // casing implementation, which uses collation to understand if we need to do Turkish casing or not.
 // casing implementation, which must apply Turkish casing only for the tr and az languages.
 if (!PlatformDetection.IsWindows && PlatformDetection.IsNotBrowser)
 {
 yield return new object[] { "en-US-POSIX", "i", "I" };
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Force GitHub README to respect dark mode
(function() {
var style = document.createElement('style');
style.textContent = '
.markdown-body {
color-scheme: dark light;
}
.markdown-body pre { background: #161b22 !important; }
.markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }
.markdown-body table th, .markdown-body table td { border-color: #30363d !important; }
.markdown-body img { background: #0d1117; }
.markdown-body blockquote { border-left-color: #8b949e; }
.markdown-body hr { border-color: #30363d; }
';
document.head.appendChild(style);
})();
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Determine Turkish casing from the locale name instead of collation#132002

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Determine Turkish casing from the locale name instead of collation
#132002
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4dc24c7

Determine Turkish casing from the locale name instead of collation


MsfPablo Aug 7, 2026
6d3b84d

Enable the Turkish casing TextInfo cases on Android


MsfPablo Aug 7, 2026
7a2a403

Fix ASCII casing fast path bypassing Turkish dispatch on Android


MsfPablo Aug 11, 2026

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15 changes: 14 additions & 1 deletion
src/libraries/System.Private.CoreLib/src/System/Globalization/TextInfo.Icu.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -14,7 +14,20 @@ private static bool NeedsTurkishCasing(string localeName)
 {
 Debug.Assert(localeName != null);

 return CultureInfo.GetCultureInfo(localeName).CompareInfo.Compare("\u0131", "I", CompareOptions.IgnoreCase) == 0;
 // ICU applies the Turkish dotted/dotless "i" casing rules to the "tr" and "az"
 // languages. This is determined from the locale name rather than by probing the
 // collation tailoring, because some platforms (notably Android, which uses the
 // system ICU) do not ship the collation data that probe relies on, which would
 // silently fall back to non-Turkish casing.
 ReadOnlySpan<char> language = localeName.AsSpan();
 int separatorIndex = language.IndexOfAny('-', '_');
 if (separatorIndex >= 0)
 {
 language = language.Slice(0, separatorIndex);
 }

 return language.Equals("tr", StringComparison.OrdinalIgnoreCase) ||
 language.Equals("az", StringComparison.OrdinalIgnoreCase);
 }

 internal unsafe void IcuChangeCase(char* src, int srcLen, char* dstBuffer, int dstBufferCapacity, bool bToUpper)
Expand Down

27 changes: 27 additions & 0 deletions
src/libraries/System.Private.CoreLib/src/System/Globalization/TextInfo.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -579,10 +579,37 @@ private bool IsAsciiCasingSameAsInvariant
 [MethodImpl(MethodImplOptions.NoInlining)]
 private void PopulateIsAsciiCasingSameAsInvariant()
 {
 // Turkish (tr / tr-*) and Azerbaijani (az / az-*) cultures have an ASCII
 // casing relationship that differs from invariant (e.g. U+0049 ↔ U+0131,
 // U+0069 ↔ U+0130). The CompareInfo.Compare probe below is unreliable on
 // platforms whose collation data is incomplete (notably the system ICU
 // on Android), where it can incorrectly report the two alphabets as
 // case-equal. Derive the answer from the locale name for those
 // languages instead, the same way IcuChangeCase decides whether to
 // dispatch through the Turkish PAL.
 if (IsLocaleWithNonInvariantAsciiCasing(_textInfoName))
 {
 _isAsciiCasingSameAsInvariant = NullableBool.False;
 return;
 }

 bool compareResult = CultureInfo.GetCultureInfo(_textInfoName).CompareInfo.Compare("abcdefghijklmnopqrstuvwxyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZ", CompareOptions.IgnoreCase) == 0;
 _isAsciiCasingSameAsInvariant = compareResult ? NullableBool.True : NullableBool.False;
 }

 private static bool IsLocaleWithNonInvariantAsciiCasing(string localeName)
 {
 ReadOnlySpan<char> language = localeName.AsSpan();
 int separatorIndex = language.IndexOfAny('-', '_');
 if (separatorIndex >= 0)
 {
 language = language.Slice(0, separatorIndex);
 }

 return language.Equals("tr", StringComparison.OrdinalIgnoreCase) ||
 language.Equals("az", StringComparison.OrdinalIgnoreCase);
 }

 /// <summary>
 /// Returns true if the dominant direction of text and UI such as the
 /// relative position of buttons and scroll bars
Expand Down

22 changes: 7 additions & 15 deletions
...ies/System.Runtime/tests/System.Globalization.Tests/System/Globalization/TextInfoTests.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -280,21 +280,17 @@ public static IEnumerable<object[]> ToLower_TestData()

 foreach (string cultureName in GetTestLocales())
 {
 // Android has its own ICU, which doesn't work well with tr
 if (!PlatformDetection.IsAndroid && !PlatformDetection.IsLinuxBionic)
 {
 yield return new object[] { cultureName, "I", "\u0131" };
 yield return new object[] { cultureName, "HI!", "h\u0131!" };
 yield return new object[] { cultureName, "HI\n\0H\u0130\t!", "h\u0131\n\0hi\u0009!" };
 }
 yield return new object[] { cultureName, "I", "\u0131" };
 yield return new object[] { cultureName, "HI!", "h\u0131!" };
 yield return new object[] { cultureName, "HI\n\0H\u0130\t!", "h\u0131\n\0hi\u0009!" };
 yield return new object[] { cultureName, "\u0130", "i" };
 yield return new object[] { cultureName, "i", "i" };

 }

 // ICU has special tailoring for the en-US-POSIX locale which treats "i" and "I" as different letters
 // instead of two letters with a case difference during collation. Make sure this doesn't confuse our
 // casing implementation, which uses collation to understand if we need to do Turkish casing or not.
 // casing implementation, which must apply Turkish casing only for the tr and az languages.
 if (!PlatformDetection.IsWindows && PlatformDetection.IsNotBrowser)
 {
 yield return new object[] { "en-US-POSIX", "I", "i" };
Expand DownExpand Up@@ -431,20 +427,16 @@ public static IEnumerable<object[]> ToUpper_TestData()
 // Turkish i
 foreach (string cultureName in GetTestLocales())
 {
 // Android has its own ICU, which doesn't work well with tr
 if (!PlatformDetection.IsAndroid && !PlatformDetection.IsLinuxBionic)
 {
 yield return new object[] { cultureName, "i", "\u0130" };
 yield return new object[] { cultureName, "H\u0131\n\0Hi\u0009!", "HI\n\0H\u0130\t!" };
 }
 yield return new object[] { cultureName, "i", "\u0130" };
 yield return new object[] { cultureName, "H\u0131\n\0Hi\u0009!", "HI\n\0H\u0130\t!" };
 yield return new object[] { cultureName, "\u0130", "\u0130" };
 yield return new object[] { cultureName, "\u0131", "I" };
 yield return new object[] { cultureName, "I", "I" };
 }

 // ICU has special tailoring for the en-US-POSIX locale which treats "i" and "I" as different letters
 // instead of two letters with a case difference during collation. Make sure this doesn't confuse our
 // casing implementation, which uses collation to understand if we need to do Turkish casing or not.
 // casing implementation, which must apply Turkish casing only for the tr and az languages.
 if (!PlatformDetection.IsWindows && PlatformDetection.IsNotBrowser)
 {
 yield return new object[] { "en-US-POSIX", "i", "I" };
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Highlight search terms from Google/DuckDuckGo/Bing referrer
(function() {
var ref = document.referrer;
var terms = [];
if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {
var url = new URL(ref);
var q = url.searchParams.get('q') || url.searchParams.get('p');
if (q) {
terms = q.split(/\s+/).filter(function(t) { return t.length > 2; });
}
}
if (terms.length === 0) return;
var style = document.createElement('style');
style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';
document.head.appendChild(style);
function highlight(node) {
if (node.nodeType === 3) { // text node
var text = node.textContent;
var found = false;
terms.forEach(function(term) {
var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\]\\]/g, '\\') + ')', 'gi');
if (regex.test(text)) {
found = true;
var frag = document.createDocumentFragment();
var parts = text.split(regex);
parts.forEach(function(part, i) {
if (i % 2 === 0) {
frag.appendChild(document.createTextNode(part));
} else {
var span = document.createElement('span');
span.className = 'userscript-highlight';
span.textContent = part;
frag.appendChild(span);
}
});
node.parentNode.replaceChild(frag, node);
}
});
} else if (node.nodeType === 1 && node.childNodes) { // element
var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];
if (!skipTags.includes(node.tagName)) {
Array.from(node.childNodes).forEach(highlight);
}
}
}
highlight(document.body);
// Re-highlight on dynamic content
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1 || node.nodeType === 3) highlight(node);
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Determine Turkish casing from the locale name instead of collation#132002

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Determine Turkish casing from the locale name instead of collation
#132002
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4dc24c7

Determine Turkish casing from the locale name instead of collation


MsfPablo Aug 7, 2026
6d3b84d

Enable the Turkish casing TextInfo cases on Android


MsfPablo Aug 7, 2026
7a2a403

Fix ASCII casing fast path bypassing Turkish dispatch on Android


MsfPablo Aug 11, 2026

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15 changes: 14 additions & 1 deletion
src/libraries/System.Private.CoreLib/src/System/Globalization/TextInfo.Icu.cs

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Original file line numberDiff line numberDiff line change
Expand Up@@ -14,7 +14,20 @@ private static bool NeedsTurkishCasing(string localeName)
 {
 Debug.Assert(localeName != null);

 return CultureInfo.GetCultureInfo(localeName).CompareInfo.Compare("\u0131", "I", CompareOptions.IgnoreCase) == 0;
 // ICU applies the Turkish dotted/dotless "i" casing rules to the "tr" and "az"
 // languages. This is determined from the locale name rather than by probing the
 // collation tailoring, because some platforms (notably Android, which uses the
 // system ICU) do not ship the collation data that probe relies on, which would
 // silently fall back to non-Turkish casing.
 ReadOnlySpan<char> language = localeName.AsSpan();
 int separatorIndex = language.IndexOfAny('-', '_');
 if (separatorIndex >= 0)
 {
 language = language.Slice(0, separatorIndex);
 }

 return language.Equals("tr", StringComparison.OrdinalIgnoreCase) ||
 language.Equals("az", StringComparison.OrdinalIgnoreCase);
 }

 internal unsafe void IcuChangeCase(char* src, int srcLen, char* dstBuffer, int dstBufferCapacity, bool bToUpper)
Expand Down

27 changes: 27 additions & 0 deletions
src/libraries/System.Private.CoreLib/src/System/Globalization/TextInfo.cs

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Original file line numberDiff line numberDiff line change
Expand Up@@ -579,10 +579,37 @@ private bool IsAsciiCasingSameAsInvariant
 [MethodImpl(MethodImplOptions.NoInlining)]
 private void PopulateIsAsciiCasingSameAsInvariant()
 {
 // Turkish (tr / tr-*) and Azerbaijani (az / az-*) cultures have an ASCII
 // casing relationship that differs from invariant (e.g. U+0049 ↔ U+0131,
 // U+0069 ↔ U+0130). The CompareInfo.Compare probe below is unreliable on
 // platforms whose collation data is incomplete (notably the system ICU
 // on Android), where it can incorrectly report the two alphabets as
 // case-equal. Derive the answer from the locale name for those
 // languages instead, the same way IcuChangeCase decides whether to
 // dispatch through the Turkish PAL.
 if (IsLocaleWithNonInvariantAsciiCasing(_textInfoName))
 {
 _isAsciiCasingSameAsInvariant = NullableBool.False;
 return;
 }

 bool compareResult = CultureInfo.GetCultureInfo(_textInfoName).CompareInfo.Compare("abcdefghijklmnopqrstuvwxyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZ", CompareOptions.IgnoreCase) == 0;
 _isAsciiCasingSameAsInvariant = compareResult ? NullableBool.True : NullableBool.False;
 }

 private static bool IsLocaleWithNonInvariantAsciiCasing(string localeName)
 {
 ReadOnlySpan<char> language = localeName.AsSpan();
 int separatorIndex = language.IndexOfAny('-', '_');
 if (separatorIndex >= 0)
 {
 language = language.Slice(0, separatorIndex);
 }

 return language.Equals("tr", StringComparison.OrdinalIgnoreCase) ||
 language.Equals("az", StringComparison.OrdinalIgnoreCase);
 }

 /// <summary>
 /// Returns true if the dominant direction of text and UI such as the
 /// relative position of buttons and scroll bars
Expand Down

22 changes: 7 additions & 15 deletions
...ies/System.Runtime/tests/System.Globalization.Tests/System/Globalization/TextInfoTests.cs

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Original file line numberDiff line numberDiff line change
Expand Up@@ -280,21 +280,17 @@ public static IEnumerable<object[]> ToLower_TestData()

 foreach (string cultureName in GetTestLocales())
 {
 // Android has its own ICU, which doesn't work well with tr
 if (!PlatformDetection.IsAndroid && !PlatformDetection.IsLinuxBionic)
 {
 yield return new object[] { cultureName, "I", "\u0131" };
 yield return new object[] { cultureName, "HI!", "h\u0131!" };
 yield return new object[] { cultureName, "HI\n\0H\u0130\t!", "h\u0131\n\0hi\u0009!" };
 }
 yield return new object[] { cultureName, "I", "\u0131" };
 yield return new object[] { cultureName, "HI!", "h\u0131!" };
 yield return new object[] { cultureName, "HI\n\0H\u0130\t!", "h\u0131\n\0hi\u0009!" };
 yield return new object[] { cultureName, "\u0130", "i" };
 yield return new object[] { cultureName, "i", "i" };

 }

 // ICU has special tailoring for the en-US-POSIX locale which treats "i" and "I" as different letters
 // instead of two letters with a case difference during collation. Make sure this doesn't confuse our
 // casing implementation, which uses collation to understand if we need to do Turkish casing or not.
 // casing implementation, which must apply Turkish casing only for the tr and az languages.
 if (!PlatformDetection.IsWindows && PlatformDetection.IsNotBrowser)
 {
 yield return new object[] { "en-US-POSIX", "I", "i" };
Expand DownExpand Up@@ -431,20 +427,16 @@ public static IEnumerable<object[]> ToUpper_TestData()
 // Turkish i
 foreach (string cultureName in GetTestLocales())
 {
 // Android has its own ICU, which doesn't work well with tr
 if (!PlatformDetection.IsAndroid && !PlatformDetection.IsLinuxBionic)
 {
 yield return new object[] { cultureName, "i", "\u0130" };
 yield return new object[] { cultureName, "H\u0131\n\0Hi\u0009!", "HI\n\0H\u0130\t!" };
 }
 yield return new object[] { cultureName, "i", "\u0130" };
 yield return new object[] { cultureName, "H\u0131\n\0Hi\u0009!", "HI\n\0H\u0130\t!" };
 yield return new object[] { cultureName, "\u0130", "\u0130" };
 yield return new object[] { cultureName, "\u0131", "I" };
 yield return new object[] { cultureName, "I", "I" };
 }

 // ICU has special tailoring for the en-US-POSIX locale which treats "i" and "I" as different letters
 // instead of two letters with a case difference during collation. Make sure this doesn't confuse our
 // casing implementation, which uses collation to understand if we need to do Turkish casing or not.
 // casing implementation, which must apply Turkish casing only for the tr and az languages.
 if (!PlatformDetection.IsWindows && PlatformDetection.IsNotBrowser)
 {
 yield return new object[] { "en-US-POSIX", "i", "I" };
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Strip utm_, fbclid, gclid, etc. from all links on page
(function() {
var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',
'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',
'ref', 'ref_src', 'source', 'medium', 'campaign'];
function cleanUrl(url) {
try {
var u = new URL(url, window.location.origin);
var changed = false;
trackingParams.forEach(function(p) {
if (u.searchParams.has(p)) {
u.searchParams.delete(p);
changed = true;
}
});
return changed ? u.toString() : url;
} catch (e) {
return url;
}
}
function cleanLinks() {
document.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
cleanLinks();
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1) {
if (node.tagName === 'A') cleanLinks();
node.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

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Determine Turkish casing from the locale name instead of collation#132002

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Determine Turkish casing from the locale name instead of collation
#132002
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4dc24c7

Determine Turkish casing from the locale name instead of collation


MsfPablo Aug 7, 2026
6d3b84d

Enable the Turkish casing TextInfo cases on Android


MsfPablo Aug 7, 2026
7a2a403

Fix ASCII casing fast path bypassing Turkish dispatch on Android


MsfPablo Aug 11, 2026

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15 changes: 14 additions & 1 deletion
src/libraries/System.Private.CoreLib/src/System/Globalization/TextInfo.Icu.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -14,7 +14,20 @@ private static bool NeedsTurkishCasing(string localeName)
 {
 Debug.Assert(localeName != null);

 return CultureInfo.GetCultureInfo(localeName).CompareInfo.Compare("\u0131", "I", CompareOptions.IgnoreCase) == 0;
 // ICU applies the Turkish dotted/dotless "i" casing rules to the "tr" and "az"
 // languages. This is determined from the locale name rather than by probing the
 // collation tailoring, because some platforms (notably Android, which uses the
 // system ICU) do not ship the collation data that probe relies on, which would
 // silently fall back to non-Turkish casing.
 ReadOnlySpan<char> language = localeName.AsSpan();
 int separatorIndex = language.IndexOfAny('-', '_');
 if (separatorIndex >= 0)
 {
 language = language.Slice(0, separatorIndex);
 }

 return language.Equals("tr", StringComparison.OrdinalIgnoreCase) ||
 language.Equals("az", StringComparison.OrdinalIgnoreCase);
 }

 internal unsafe void IcuChangeCase(char* src, int srcLen, char* dstBuffer, int dstBufferCapacity, bool bToUpper)
Expand Down

27 changes: 27 additions & 0 deletions
src/libraries/System.Private.CoreLib/src/System/Globalization/TextInfo.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -579,10 +579,37 @@ private bool IsAsciiCasingSameAsInvariant
 [MethodImpl(MethodImplOptions.NoInlining)]
 private void PopulateIsAsciiCasingSameAsInvariant()
 {
 // Turkish (tr / tr-*) and Azerbaijani (az / az-*) cultures have an ASCII
 // casing relationship that differs from invariant (e.g. U+0049 ↔ U+0131,
 // U+0069 ↔ U+0130). The CompareInfo.Compare probe below is unreliable on
 // platforms whose collation data is incomplete (notably the system ICU
 // on Android), where it can incorrectly report the two alphabets as
 // case-equal. Derive the answer from the locale name for those
 // languages instead, the same way IcuChangeCase decides whether to
 // dispatch through the Turkish PAL.
 if (IsLocaleWithNonInvariantAsciiCasing(_textInfoName))
 {
 _isAsciiCasingSameAsInvariant = NullableBool.False;
 return;
 }

 bool compareResult = CultureInfo.GetCultureInfo(_textInfoName).CompareInfo.Compare("abcdefghijklmnopqrstuvwxyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZ", CompareOptions.IgnoreCase) == 0;
 _isAsciiCasingSameAsInvariant = compareResult ? NullableBool.True : NullableBool.False;
 }

 private static bool IsLocaleWithNonInvariantAsciiCasing(string localeName)
 {
 ReadOnlySpan<char> language = localeName.AsSpan();
 int separatorIndex = language.IndexOfAny('-', '_');
 if (separatorIndex >= 0)
 {
 language = language.Slice(0, separatorIndex);
 }

 return language.Equals("tr", StringComparison.OrdinalIgnoreCase) ||
 language.Equals("az", StringComparison.OrdinalIgnoreCase);
 }

 /// <summary>
 /// Returns true if the dominant direction of text and UI such as the
 /// relative position of buttons and scroll bars
Expand Down

22 changes: 7 additions & 15 deletions
...ies/System.Runtime/tests/System.Globalization.Tests/System/Globalization/TextInfoTests.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -280,21 +280,17 @@ public static IEnumerable<object[]> ToLower_TestData()

 foreach (string cultureName in GetTestLocales())
 {
 // Android has its own ICU, which doesn't work well with tr
 if (!PlatformDetection.IsAndroid && !PlatformDetection.IsLinuxBionic)
 {
 yield return new object[] { cultureName, "I", "\u0131" };
 yield return new object[] { cultureName, "HI!", "h\u0131!" };
 yield return new object[] { cultureName, "HI\n\0H\u0130\t!", "h\u0131\n\0hi\u0009!" };
 }
 yield return new object[] { cultureName, "I", "\u0131" };
 yield return new object[] { cultureName, "HI!", "h\u0131!" };
 yield return new object[] { cultureName, "HI\n\0H\u0130\t!", "h\u0131\n\0hi\u0009!" };
 yield return new object[] { cultureName, "\u0130", "i" };
 yield return new object[] { cultureName, "i", "i" };

 }

 // ICU has special tailoring for the en-US-POSIX locale which treats "i" and "I" as different letters
 // instead of two letters with a case difference during collation. Make sure this doesn't confuse our
 // casing implementation, which uses collation to understand if we need to do Turkish casing or not.
 // casing implementation, which must apply Turkish casing only for the tr and az languages.
 if (!PlatformDetection.IsWindows && PlatformDetection.IsNotBrowser)
 {
 yield return new object[] { "en-US-POSIX", "I", "i" };
Expand DownExpand Up@@ -431,20 +427,16 @@ public static IEnumerable<object[]> ToUpper_TestData()
 // Turkish i
 foreach (string cultureName in GetTestLocales())
 {
 // Android has its own ICU, which doesn't work well with tr
 if (!PlatformDetection.IsAndroid && !PlatformDetection.IsLinuxBionic)
 {
 yield return new object[] { cultureName, "i", "\u0130" };
 yield return new object[] { cultureName, "H\u0131\n\0Hi\u0009!", "HI\n\0H\u0130\t!" };
 }
 yield return new object[] { cultureName, "i", "\u0130" };
 yield return new object[] { cultureName, "H\u0131\n\0Hi\u0009!", "HI\n\0H\u0130\t!" };
 yield return new object[] { cultureName, "\u0130", "\u0130" };
 yield return new object[] { cultureName, "\u0131", "I" };
 yield return new object[] { cultureName, "I", "I" };
 }

 // ICU has special tailoring for the en-US-POSIX locale which treats "i" and "I" as different letters
 // instead of two letters with a case difference during collation. Make sure this doesn't confuse our
 // casing implementation, which uses collation to understand if we need to do Turkish casing or not.
 // casing implementation, which must apply Turkish casing only for the tr and az languages.
 if (!PlatformDetection.IsWindows && PlatformDetection.IsNotBrowser)
 {
 yield return new object[] { "en-US-POSIX", "i", "I" };
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Auto-enable theater mode on YouTube
(function() {
function tryTheater() {
var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]');
if (btn && !btn.classList.contains('activated')) {
btn.click();
}
}
// Try immediately
tryTheater();
// Try after navigation (SPA)
var lastUrl = location.href;
setInterval(function() {
if (location.href !== lastUrl) {
lastUrl = location.href;
setTimeout(tryTheater, 500);
}
}, 1000);
// Also try on player load
var observer = new MutationObserver(tryTheater);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Determine Turkish casing from the locale name instead of collation#132002

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Determine Turkish casing from the locale name instead of collation
#132002
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4dc24c7

Determine Turkish casing from the locale name instead of collation


MsfPablo Aug 7, 2026
6d3b84d

Enable the Turkish casing TextInfo cases on Android


MsfPablo Aug 7, 2026
7a2a403

Fix ASCII casing fast path bypassing Turkish dispatch on Android


MsfPablo Aug 11, 2026

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15 changes: 14 additions & 1 deletion
src/libraries/System.Private.CoreLib/src/System/Globalization/TextInfo.Icu.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -14,7 +14,20 @@ private static bool NeedsTurkishCasing(string localeName)
 {
 Debug.Assert(localeName != null);

 return CultureInfo.GetCultureInfo(localeName).CompareInfo.Compare("\u0131", "I", CompareOptions.IgnoreCase) == 0;
 // ICU applies the Turkish dotted/dotless "i" casing rules to the "tr" and "az"
 // languages. This is determined from the locale name rather than by probing the
 // collation tailoring, because some platforms (notably Android, which uses the
 // system ICU) do not ship the collation data that probe relies on, which would
 // silently fall back to non-Turkish casing.
 ReadOnlySpan<char> language = localeName.AsSpan();
 int separatorIndex = language.IndexOfAny('-', '_');
 if (separatorIndex >= 0)
 {
 language = language.Slice(0, separatorIndex);
 }

 return language.Equals("tr", StringComparison.OrdinalIgnoreCase) ||
 language.Equals("az", StringComparison.OrdinalIgnoreCase);
 }

 internal unsafe void IcuChangeCase(char* src, int srcLen, char* dstBuffer, int dstBufferCapacity, bool bToUpper)
Expand Down

27 changes: 27 additions & 0 deletions
src/libraries/System.Private.CoreLib/src/System/Globalization/TextInfo.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -579,10 +579,37 @@ private bool IsAsciiCasingSameAsInvariant
 [MethodImpl(MethodImplOptions.NoInlining)]
 private void PopulateIsAsciiCasingSameAsInvariant()
 {
 // Turkish (tr / tr-*) and Azerbaijani (az / az-*) cultures have an ASCII
 // casing relationship that differs from invariant (e.g. U+0049 ↔ U+0131,
 // U+0069 ↔ U+0130). The CompareInfo.Compare probe below is unreliable on
 // platforms whose collation data is incomplete (notably the system ICU
 // on Android), where it can incorrectly report the two alphabets as
 // case-equal. Derive the answer from the locale name for those
 // languages instead, the same way IcuChangeCase decides whether to
 // dispatch through the Turkish PAL.
 if (IsLocaleWithNonInvariantAsciiCasing(_textInfoName))
 {
 _isAsciiCasingSameAsInvariant = NullableBool.False;
 return;
 }

 bool compareResult = CultureInfo.GetCultureInfo(_textInfoName).CompareInfo.Compare("abcdefghijklmnopqrstuvwxyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZ", CompareOptions.IgnoreCase) == 0;
 _isAsciiCasingSameAsInvariant = compareResult ? NullableBool.True : NullableBool.False;
 }

 private static bool IsLocaleWithNonInvariantAsciiCasing(string localeName)
 {
 ReadOnlySpan<char> language = localeName.AsSpan();
 int separatorIndex = language.IndexOfAny('-', '_');
 if (separatorIndex >= 0)
 {
 language = language.Slice(0, separatorIndex);
 }

 return language.Equals("tr", StringComparison.OrdinalIgnoreCase) ||
 language.Equals("az", StringComparison.OrdinalIgnoreCase);
 }

 /// <summary>
 /// Returns true if the dominant direction of text and UI such as the
 /// relative position of buttons and scroll bars
Expand Down

22 changes: 7 additions & 15 deletions
...ies/System.Runtime/tests/System.Globalization.Tests/System/Globalization/TextInfoTests.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -280,21 +280,17 @@ public static IEnumerable<object[]> ToLower_TestData()

 foreach (string cultureName in GetTestLocales())
 {
 // Android has its own ICU, which doesn't work well with tr
 if (!PlatformDetection.IsAndroid && !PlatformDetection.IsLinuxBionic)
 {
 yield return new object[] { cultureName, "I", "\u0131" };
 yield return new object[] { cultureName, "HI!", "h\u0131!" };
 yield return new object[] { cultureName, "HI\n\0H\u0130\t!", "h\u0131\n\0hi\u0009!" };
 }
 yield return new object[] { cultureName, "I", "\u0131" };
 yield return new object[] { cultureName, "HI!", "h\u0131!" };
 yield return new object[] { cultureName, "HI\n\0H\u0130\t!", "h\u0131\n\0hi\u0009!" };
 yield return new object[] { cultureName, "\u0130", "i" };
 yield return new object[] { cultureName, "i", "i" };

 }

 // ICU has special tailoring for the en-US-POSIX locale which treats "i" and "I" as different letters
 // instead of two letters with a case difference during collation. Make sure this doesn't confuse our
 // casing implementation, which uses collation to understand if we need to do Turkish casing or not.
 // casing implementation, which must apply Turkish casing only for the tr and az languages.
 if (!PlatformDetection.IsWindows && PlatformDetection.IsNotBrowser)
 {
 yield return new object[] { "en-US-POSIX", "I", "i" };
Expand DownExpand Up@@ -431,20 +427,16 @@ public static IEnumerable<object[]> ToUpper_TestData()
 // Turkish i
 foreach (string cultureName in GetTestLocales())
 {
 // Android has its own ICU, which doesn't work well with tr
 if (!PlatformDetection.IsAndroid && !PlatformDetection.IsLinuxBionic)
 {
 yield return new object[] { cultureName, "i", "\u0130" };
 yield return new object[] { cultureName, "H\u0131\n\0Hi\u0009!", "HI\n\0H\u0130\t!" };
 }
 yield return new object[] { cultureName, "i", "\u0130" };
 yield return new object[] { cultureName, "H\u0131\n\0Hi\u0009!", "HI\n\0H\u0130\t!" };
 yield return new object[] { cultureName, "\u0130", "\u0130" };
 yield return new object[] { cultureName, "\u0131", "I" };
 yield return new object[] { cultureName, "I", "I" };
 }

 // ICU has special tailoring for the en-US-POSIX locale which treats "i" and "I" as different letters
 // instead of two letters with a case difference during collation. Make sure this doesn't confuse our
 // casing implementation, which uses collation to understand if we need to do Turkish casing or not.
 // casing implementation, which must apply Turkish casing only for the tr and az languages.
 if (!PlatformDetection.IsWindows && PlatformDetection.IsNotBrowser)
 {
 yield return new object[] { "en-US-POSIX", "i", "I" };
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Remove or un-stick sticky/fixed headers that block content
(function() {
function unstick() {
document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) {
if (el.style.position === 'fixed' || el.style.position === 'sticky' || getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {
el.style.position = 'static';
el.style.top = 'auto';
el.style.zIndex = 'auto';
}
});
}
unstick();
var observer = new MutationObserver(unstick);
observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });
})();
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Determine Turkish casing from the locale name instead of collation#132002

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Determine Turkish casing from the locale name instead of collation
#132002
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4dc24c7

Determine Turkish casing from the locale name instead of collation


MsfPablo Aug 7, 2026
6d3b84d

Enable the Turkish casing TextInfo cases on Android


MsfPablo Aug 7, 2026
7a2a403

Fix ASCII casing fast path bypassing Turkish dispatch on Android


MsfPablo Aug 11, 2026

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15 changes: 14 additions & 1 deletion
src/libraries/System.Private.CoreLib/src/System/Globalization/TextInfo.Icu.cs

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Original file line numberDiff line numberDiff line change
Expand Up@@ -14,7 +14,20 @@ private static bool NeedsTurkishCasing(string localeName)
 {
 Debug.Assert(localeName != null);

 return CultureInfo.GetCultureInfo(localeName).CompareInfo.Compare("\u0131", "I", CompareOptions.IgnoreCase) == 0;
 // ICU applies the Turkish dotted/dotless "i" casing rules to the "tr" and "az"
 // languages. This is determined from the locale name rather than by probing the
 // collation tailoring, because some platforms (notably Android, which uses the
 // system ICU) do not ship the collation data that probe relies on, which would
 // silently fall back to non-Turkish casing.
 ReadOnlySpan<char> language = localeName.AsSpan();
 int separatorIndex = language.IndexOfAny('-', '_');
 if (separatorIndex >= 0)
 {
 language = language.Slice(0, separatorIndex);
 }

 return language.Equals("tr", StringComparison.OrdinalIgnoreCase) ||
 language.Equals("az", StringComparison.OrdinalIgnoreCase);
 }

 internal unsafe void IcuChangeCase(char* src, int srcLen, char* dstBuffer, int dstBufferCapacity, bool bToUpper)
Expand Down

27 changes: 27 additions & 0 deletions
src/libraries/System.Private.CoreLib/src/System/Globalization/TextInfo.cs

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Original file line numberDiff line numberDiff line change
Expand Up@@ -579,10 +579,37 @@ private bool IsAsciiCasingSameAsInvariant
 [MethodImpl(MethodImplOptions.NoInlining)]
 private void PopulateIsAsciiCasingSameAsInvariant()
 {
 // Turkish (tr / tr-*) and Azerbaijani (az / az-*) cultures have an ASCII
 // casing relationship that differs from invariant (e.g. U+0049 ↔ U+0131,
 // U+0069 ↔ U+0130). The CompareInfo.Compare probe below is unreliable on
 // platforms whose collation data is incomplete (notably the system ICU
 // on Android), where it can incorrectly report the two alphabets as
 // case-equal. Derive the answer from the locale name for those
 // languages instead, the same way IcuChangeCase decides whether to
 // dispatch through the Turkish PAL.
 if (IsLocaleWithNonInvariantAsciiCasing(_textInfoName))
 {
 _isAsciiCasingSameAsInvariant = NullableBool.False;
 return;
 }

 bool compareResult = CultureInfo.GetCultureInfo(_textInfoName).CompareInfo.Compare("abcdefghijklmnopqrstuvwxyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZ", CompareOptions.IgnoreCase) == 0;
 _isAsciiCasingSameAsInvariant = compareResult ? NullableBool.True : NullableBool.False;
 }

 private static bool IsLocaleWithNonInvariantAsciiCasing(string localeName)
 {
 ReadOnlySpan<char> language = localeName.AsSpan();
 int separatorIndex = language.IndexOfAny('-', '_');
 if (separatorIndex >= 0)
 {
 language = language.Slice(0, separatorIndex);
 }

 return language.Equals("tr", StringComparison.OrdinalIgnoreCase) ||
 language.Equals("az", StringComparison.OrdinalIgnoreCase);
 }

 /// <summary>
 /// Returns true if the dominant direction of text and UI such as the
 /// relative position of buttons and scroll bars
Expand Down

22 changes: 7 additions & 15 deletions
...ies/System.Runtime/tests/System.Globalization.Tests/System/Globalization/TextInfoTests.cs

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Original file line numberDiff line numberDiff line change
Expand Up@@ -280,21 +280,17 @@ public static IEnumerable<object[]> ToLower_TestData()

 foreach (string cultureName in GetTestLocales())
 {
 // Android has its own ICU, which doesn't work well with tr
 if (!PlatformDetection.IsAndroid && !PlatformDetection.IsLinuxBionic)
 {
 yield return new object[] { cultureName, "I", "\u0131" };
 yield return new object[] { cultureName, "HI!", "h\u0131!" };
 yield return new object[] { cultureName, "HI\n\0H\u0130\t!", "h\u0131\n\0hi\u0009!" };
 }
 yield return new object[] { cultureName, "I", "\u0131" };
 yield return new object[] { cultureName, "HI!", "h\u0131!" };
 yield return new object[] { cultureName, "HI\n\0H\u0130\t!", "h\u0131\n\0hi\u0009!" };
 yield return new object[] { cultureName, "\u0130", "i" };
 yield return new object[] { cultureName, "i", "i" };

 }

 // ICU has special tailoring for the en-US-POSIX locale which treats "i" and "I" as different letters
 // instead of two letters with a case difference during collation. Make sure this doesn't confuse our
 // casing implementation, which uses collation to understand if we need to do Turkish casing or not.
 // casing implementation, which must apply Turkish casing only for the tr and az languages.
 if (!PlatformDetection.IsWindows && PlatformDetection.IsNotBrowser)
 {
 yield return new object[] { "en-US-POSIX", "I", "i" };
Expand DownExpand Up@@ -431,20 +427,16 @@ public static IEnumerable<object[]> ToUpper_TestData()
 // Turkish i
 foreach (string cultureName in GetTestLocales())
 {
 // Android has its own ICU, which doesn't work well with tr
 if (!PlatformDetection.IsAndroid && !PlatformDetection.IsLinuxBionic)
 {
 yield return new object[] { cultureName, "i", "\u0130" };
 yield return new object[] { cultureName, "H\u0131\n\0Hi\u0009!", "HI\n\0H\u0130\t!" };
 }
 yield return new object[] { cultureName, "i", "\u0130" };
 yield return new object[] { cultureName, "H\u0131\n\0Hi\u0009!", "HI\n\0H\u0130\t!" };
 yield return new object[] { cultureName, "\u0130", "\u0130" };
 yield return new object[] { cultureName, "\u0131", "I" };
 yield return new object[] { cultureName, "I", "I" };
 }

 // ICU has special tailoring for the en-US-POSIX locale which treats "i" and "I" as different letters
 // instead of two letters with a case difference during collation. Make sure this doesn't confuse our
 // casing implementation, which uses collation to understand if we need to do Turkish casing or not.
 // casing implementation, which must apply Turkish casing only for the tr and az languages.
 if (!PlatformDetection.IsWindows && PlatformDetection.IsNotBrowser)
 {
 yield return new object[] { "en-US-POSIX", "i", "I" };
Expand Down
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Universal Dark Mode - works on any site
(function() {
var enabled = true;
function applyDarkMode() {
if (!enabled) return;
// Create style element if it doesn't exist
var style = document.getElementById('universal-dark-mode-style');
if (!style) {
style = document.createElement('style');
style.id = 'universal-dark-mode-style';
document.head.appendChild(style);
}
// Dark mode CSS - inverts colors but preserves images/video
style.textContent = '
/* Invert everything except media */
html {
filter: invert(1) hue-rotate(180deg) !important;
background: #1a1a2e !important;
}
/* Restore images, videos, iframes, canvas */
img, video, iframe, canvas, svg, picture, [style*="background-image"] {
filter: invert(1) hue-rotate(180deg) !important;
}
/* Preserve specific elements that should not be inverted */
.no-dark-mode, .no-dark-mode *,
[data-theme="light"], [data-theme="light"],
.ace_editor, .ace_editor *,
.CodeMirror, .CodeMirror *,
.monaco-editor, .monaco-editor *,
.markdown-body pre, .markdown-body pre *,
.highlight, .highlight *,
pre code, pre code * {
filter: none !important;
}
/* Fix common UI elements */
.modal, .popup, .dropdown-menu, .tooltip, .popover {
filter: invert(1) hue-rotate(180deg) !important;
background: #2d2d44 !important;
border-color: #444 !important;
}
/* Scrollbars */
::-webkit-scrollbar { background: #1a1a2e !important; }
::-webkit-scrollbar-thumb { background: #444 !important; }
::-webkit-scrollbar-thumb:hover { background: #555 !important; }
/* Selection */
::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
';
}
function removeDarkMode() {
var style = document.getElementById('universal-dark-mode-style');
if (style) style.remove();
}
// Toggle with Alt+Shift+D
document.addEventListener('keydown', function(e) {
if (e.altKey && e.shiftKey && e.key === 'D') {
e.preventDefault();
enabled = !enabled;
if (enabled) {
applyDarkMode();
console.log('[Universal Dark Mode] Enabled');
} else {
removeDarkMode();
console.log('[Universal Dark Mode] Disabled');
}
}
});
// Apply on load
applyDarkMode();
// Re-apply on dynamic content
var observer = new MutationObserver(function(mutations) {
if (enabled && !document.getElementById('universal-dark-mode-style')) {
applyDarkMode();
}
});
observer.observe(document.head, { childList: true });
console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');
})();
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

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Determine Turkish casing from the locale name instead of collation#132002

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Determine Turkish casing from the locale name instead of collation
#132002
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4dc24c7

Determine Turkish casing from the locale name instead of collation


MsfPablo Aug 7, 2026
6d3b84d

Enable the Turkish casing TextInfo cases on Android


MsfPablo Aug 7, 2026
7a2a403

Fix ASCII casing fast path bypassing Turkish dispatch on Android


MsfPablo Aug 11, 2026

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15 changes: 14 additions & 1 deletion
src/libraries/System.Private.CoreLib/src/System/Globalization/TextInfo.Icu.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -14,7 +14,20 @@ private static bool NeedsTurkishCasing(string localeName)
 {
 Debug.Assert(localeName != null);

 return CultureInfo.GetCultureInfo(localeName).CompareInfo.Compare("\u0131", "I", CompareOptions.IgnoreCase) == 0;
 // ICU applies the Turkish dotted/dotless "i" casing rules to the "tr" and "az"
 // languages. This is determined from the locale name rather than by probing the
 // collation tailoring, because some platforms (notably Android, which uses the
 // system ICU) do not ship the collation data that probe relies on, which would
 // silently fall back to non-Turkish casing.
 ReadOnlySpan<char> language = localeName.AsSpan();
 int separatorIndex = language.IndexOfAny('-', '_');
 if (separatorIndex >= 0)
 {
 language = language.Slice(0, separatorIndex);
 }

 return language.Equals("tr", StringComparison.OrdinalIgnoreCase) ||
 language.Equals("az", StringComparison.OrdinalIgnoreCase);
 }

 internal unsafe void IcuChangeCase(char* src, int srcLen, char* dstBuffer, int dstBufferCapacity, bool bToUpper)
Expand Down

27 changes: 27 additions & 0 deletions
src/libraries/System.Private.CoreLib/src/System/Globalization/TextInfo.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -579,10 +579,37 @@ private bool IsAsciiCasingSameAsInvariant
 [MethodImpl(MethodImplOptions.NoInlining)]
 private void PopulateIsAsciiCasingSameAsInvariant()
 {
 // Turkish (tr / tr-*) and Azerbaijani (az / az-*) cultures have an ASCII
 // casing relationship that differs from invariant (e.g. U+0049 ↔ U+0131,
 // U+0069 ↔ U+0130). The CompareInfo.Compare probe below is unreliable on
 // platforms whose collation data is incomplete (notably the system ICU
 // on Android), where it can incorrectly report the two alphabets as
 // case-equal. Derive the answer from the locale name for those
 // languages instead, the same way IcuChangeCase decides whether to
 // dispatch through the Turkish PAL.
 if (IsLocaleWithNonInvariantAsciiCasing(_textInfoName))
 {
 _isAsciiCasingSameAsInvariant = NullableBool.False;
 return;
 }

 bool compareResult = CultureInfo.GetCultureInfo(_textInfoName).CompareInfo.Compare("abcdefghijklmnopqrstuvwxyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZ", CompareOptions.IgnoreCase) == 0;
 _isAsciiCasingSameAsInvariant = compareResult ? NullableBool.True : NullableBool.False;
 }

 private static bool IsLocaleWithNonInvariantAsciiCasing(string localeName)
 {
 ReadOnlySpan<char> language = localeName.AsSpan();
 int separatorIndex = language.IndexOfAny('-', '_');
 if (separatorIndex >= 0)
 {
 language = language.Slice(0, separatorIndex);
 }

 return language.Equals("tr", StringComparison.OrdinalIgnoreCase) ||
 language.Equals("az", StringComparison.OrdinalIgnoreCase);
 }

 /// <summary>
 /// Returns true if the dominant direction of text and UI such as the
 /// relative position of buttons and scroll bars
Expand Down

22 changes: 7 additions & 15 deletions
...ies/System.Runtime/tests/System.Globalization.Tests/System/Globalization/TextInfoTests.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -280,21 +280,17 @@ public static IEnumerable<object[]> ToLower_TestData()

 foreach (string cultureName in GetTestLocales())
 {
 // Android has its own ICU, which doesn't work well with tr
 if (!PlatformDetection.IsAndroid && !PlatformDetection.IsLinuxBionic)
 {
 yield return new object[] { cultureName, "I", "\u0131" };
 yield return new object[] { cultureName, "HI!", "h\u0131!" };
 yield return new object[] { cultureName, "HI\n\0H\u0130\t!", "h\u0131\n\0hi\u0009!" };
 }
 yield return new object[] { cultureName, "I", "\u0131" };
 yield return new object[] { cultureName, "HI!", "h\u0131!" };
 yield return new object[] { cultureName, "HI\n\0H\u0130\t!", "h\u0131\n\0hi\u0009!" };
 yield return new object[] { cultureName, "\u0130", "i" };
 yield return new object[] { cultureName, "i", "i" };

 }

 // ICU has special tailoring for the en-US-POSIX locale which treats "i" and "I" as different letters
 // instead of two letters with a case difference during collation. Make sure this doesn't confuse our
 // casing implementation, which uses collation to understand if we need to do Turkish casing or not.
 // casing implementation, which must apply Turkish casing only for the tr and az languages.
 if (!PlatformDetection.IsWindows && PlatformDetection.IsNotBrowser)
 {
 yield return new object[] { "en-US-POSIX", "I", "i" };
Expand DownExpand Up@@ -431,20 +427,16 @@ public static IEnumerable<object[]> ToUpper_TestData()
 // Turkish i
 foreach (string cultureName in GetTestLocales())
 {
 // Android has its own ICU, which doesn't work well with tr
 if (!PlatformDetection.IsAndroid && !PlatformDetection.IsLinuxBionic)
 {
 yield return new object[] { cultureName, "i", "\u0130" };
 yield return new object[] { cultureName, "H\u0131\n\0Hi\u0009!", "HI\n\0H\u0130\t!" };
 }
 yield return new object[] { cultureName, "i", "\u0130" };
 yield return new object[] { cultureName, "H\u0131\n\0Hi\u0009!", "HI\n\0H\u0130\t!" };
 yield return new object[] { cultureName, "\u0130", "\u0130" };
 yield return new object[] { cultureName, "\u0131", "I" };
 yield return new object[] { cultureName, "I", "I" };
 }

 // ICU has special tailoring for the en-US-POSIX locale which treats "i" and "I" as different letters
 // instead of two letters with a case difference during collation. Make sure this doesn't confuse our
 // casing implementation, which uses collation to understand if we need to do Turkish casing or not.
 // casing implementation, which must apply Turkish casing only for the tr and az languages.
 if (!PlatformDetection.IsWindows && PlatformDetection.IsNotBrowser)
 {
 yield return new object[] { "en-US-POSIX", "i", "I" };
Expand Down
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