Breaking change: Improved String.LastIndexOf handling of empty values #21372

Closed
#21375
Closed
Breaking change: Improved String.LastIndexOf handling of empty values#21372
#21375
Assignees
gewarren
Labels
🏁 Release: .NET 5Work items for the .NET 5 releasebreaking-changeIndicates a .NET Core breaking change

Description

@GrabYourPitchforks
GrabYourPitchforks
opened on Nov 6, 2020

Breaking change: Improved String.LastIndexOf handling of empty values

string.LastIndexOf and related APIs now return correct values when searching for a zero-length (or zero-length equivalent) substring within a larger string.

Version introduced

.NET 5.0

Old behavior

In .NET Framework and .NET Core, string.LastIndexOf and related APIs could return an incorrect value when the caller searches for a zero-length substring.

Console.WriteLine("Hello".LastIndexOf(""));// prints '4' (incorrect)ReadOnlySpan<char>span="Hello";Console.WriteLine(span.LastIndexOf(""));// prints '0' (incorrect)

New behavior

Beginning with .NET 5.0, these APIs return the correct value for LastIndexOf.

Console.WriteLine("Hello".LastIndexOf(""));// prints '5' (correct)ReadOnlySpan<char>span="Hello";Console.WriteLine(span.LastIndexOf(""));// prints '5' (correct)

In these examples, 5 is the correct answer because "Hello".Substring(5) and "Hello".AsSpan().Slice(5) both produce an empty string, which is trivially equal to the empty substring being sought.

Reason for change

This change was part of an overall bug fixing effort around string handling for .NET 5. This also helps unify our behavior between Windows and non-Windows platforms. See dotnet/runtime#13383 and dotnet/runtime#13382 for more information.

Recommended action

Developers needn't take any action. The .NET 5.0 runtime provides the new behaviors automatically.

There is no compatibility switch to restore the old behavior.

Category

  • Core .NET libraries

Affected APIs

Issue metadata

  • Issue type: breaking-change

Metadata

Metadata

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Labels

🏁 Release: .NET 5Work items for the .NET 5 releasebreaking-changeIndicates a .NET Core breaking change

Type

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No projects

    Milestone

    No milestone

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    None yet

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    , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
     blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n 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;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

    Skip to content
    Breaking change: Improved String.LastIndexOf handling of empty values #21372
    Closed
    #21375
    Closed
    Breaking change: Improved String.LastIndexOf handling of empty values#21372
    #21375
    Assignees
    gewarren
    Labels
    🏁 Release: .NET 5Work items for the .NET 5 releasebreaking-changeIndicates a .NET Core breaking change
    Description
    @GrabYourPitchforks
    GrabYourPitchforks
    opened on Nov 6, 2020
    Breaking change: Improved String.LastIndexOf handling of empty values
    string.LastIndexOf and related APIs now return correct values when searching for a zero-length (or zero-length equivalent) substring within a larger string.
    Version introduced
    .NET 5.0
    Old behavior
    In .NET Framework and .NET Core, string.LastIndexOf and related APIs could return an incorrect value when the caller searches for a zero-length substring.
    Console.WriteLine("Hello".LastIndexOf(""));// prints '4' (incorrect)ReadOnlySpan<char>span="Hello";Console.WriteLine(span.LastIndexOf(""));// prints '0' (incorrect)
    New behavior
    Beginning with .NET 5.0, these APIs return the correct value for LastIndexOf.
    Console.WriteLine("Hello".LastIndexOf(""));// prints '5' (correct)ReadOnlySpan<char>span="Hello";Console.WriteLine(span.LastIndexOf(""));// prints '5' (correct)
    In these examples, 5 is the correct answer because "Hello".Substring(5) and "Hello".AsSpan().Slice(5) both produce an empty string, which is trivially equal to the empty substring being sought.
    Reason for change
    This change was part of an overall bug fixing effort around string handling for .NET 5. This also helps unify our behavior between Windows and non-Windows platforms. See dotnet/runtime#13383 and dotnet/runtime#13382 for more information.
    Recommended action
    Developers needn't take any action. The .NET 5.0 runtime provides the new behaviors automatically.
    There is no compatibility switch to restore the old behavior.
    Category
    • Core .NET libraries
    Affected APIs
    Issue metadata
    • Issue type: breaking-change
    Metadata
    Metadata
    Assignees
    Labels
    🏁 Release: .NET 5Work items for the .NET 5 releasebreaking-changeIndicates a .NET Core breaking change
    Type
    No type
    Projects
    No projects
      Milestone
      No milestone
      Relationships
      None yet
      Development
      No branches or pull requests
      Issue actions
      
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

      Skip to content
      Breaking change: Improved String.LastIndexOf handling of empty values #21372
      Closed
      #21375
      Closed
      Breaking change: Improved String.LastIndexOf handling of empty values#21372
      #21375
      Assignees
      gewarren
      Labels
      🏁 Release: .NET 5Work items for the .NET 5 releasebreaking-changeIndicates a .NET Core breaking change
      Description
      @GrabYourPitchforks
      GrabYourPitchforks
      opened on Nov 6, 2020
      Breaking change: Improved String.LastIndexOf handling of empty values
      string.LastIndexOf and related APIs now return correct values when searching for a zero-length (or zero-length equivalent) substring within a larger string.
      Version introduced
      .NET 5.0
      Old behavior
      In .NET Framework and .NET Core, string.LastIndexOf and related APIs could return an incorrect value when the caller searches for a zero-length substring.
      Console.WriteLine("Hello".LastIndexOf(""));// prints '4' (incorrect)ReadOnlySpan<char>span="Hello";Console.WriteLine(span.LastIndexOf(""));// prints '0' (incorrect)
      New behavior
      Beginning with .NET 5.0, these APIs return the correct value for LastIndexOf.
      Console.WriteLine("Hello".LastIndexOf(""));// prints '5' (correct)ReadOnlySpan<char>span="Hello";Console.WriteLine(span.LastIndexOf(""));// prints '5' (correct)
      In these examples, 5 is the correct answer because "Hello".Substring(5) and "Hello".AsSpan().Slice(5) both produce an empty string, which is trivially equal to the empty substring being sought.
      Reason for change
      This change was part of an overall bug fixing effort around string handling for .NET 5. This also helps unify our behavior between Windows and non-Windows platforms. See dotnet/runtime#13383 and dotnet/runtime#13382 for more information.
      Recommended action
      Developers needn't take any action. The .NET 5.0 runtime provides the new behaviors automatically.
      There is no compatibility switch to restore the old behavior.
      Category
      • Core .NET libraries
      Affected APIs
      Issue metadata
      • Issue type: breaking-change
      Metadata
      Metadata
      Assignees
      Labels
      🏁 Release: .NET 5Work items for the .NET 5 releasebreaking-changeIndicates a .NET Core breaking change
      Type
      No type
      Projects
      No projects
        Milestone
        No milestone
        Relationships
        None yet
        Development
        No branches or pull requests
        Issue actions
        
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

        Skip to content
        Breaking change: Improved String.LastIndexOf handling of empty values #21372
        Closed
        #21375
        Closed
        Breaking change: Improved String.LastIndexOf handling of empty values#21372
        #21375
        Assignees
        gewarren
        Labels
        🏁 Release: .NET 5Work items for the .NET 5 releasebreaking-changeIndicates a .NET Core breaking change
        Description
        @GrabYourPitchforks
        GrabYourPitchforks
        opened on Nov 6, 2020
        Breaking change: Improved String.LastIndexOf handling of empty values
        string.LastIndexOf and related APIs now return correct values when searching for a zero-length (or zero-length equivalent) substring within a larger string.
        Version introduced
        .NET 5.0
        Old behavior
        In .NET Framework and .NET Core, string.LastIndexOf and related APIs could return an incorrect value when the caller searches for a zero-length substring.
        Console.WriteLine("Hello".LastIndexOf(""));// prints '4' (incorrect)ReadOnlySpan<char>span="Hello";Console.WriteLine(span.LastIndexOf(""));// prints '0' (incorrect)
        New behavior
        Beginning with .NET 5.0, these APIs return the correct value for LastIndexOf.
        Console.WriteLine("Hello".LastIndexOf(""));// prints '5' (correct)ReadOnlySpan<char>span="Hello";Console.WriteLine(span.LastIndexOf(""));// prints '5' (correct)
        In these examples, 5 is the correct answer because "Hello".Substring(5) and "Hello".AsSpan().Slice(5) both produce an empty string, which is trivially equal to the empty substring being sought.
        Reason for change
        This change was part of an overall bug fixing effort around string handling for .NET 5. This also helps unify our behavior between Windows and non-Windows platforms. See dotnet/runtime#13383 and dotnet/runtime#13382 for more information.
        Recommended action
        Developers needn't take any action. The .NET 5.0 runtime provides the new behaviors automatically.
        There is no compatibility switch to restore the old behavior.
        Category
        • Core .NET libraries
        Affected APIs
        Issue metadata
        • Issue type: breaking-change
        Metadata
        Metadata
        Assignees
        Labels
        🏁 Release: .NET 5Work items for the .NET 5 releasebreaking-changeIndicates a .NET Core breaking change
        Type
        No type
        Projects
        No projects
          Milestone
          No milestone
          Relationships
          None yet
          Development
          No branches or pull requests
          Issue actions
          
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

          Skip to content
          Breaking change: Improved String.LastIndexOf handling of empty values #21372
          Closed
          #21375
          Closed
          Breaking change: Improved String.LastIndexOf handling of empty values#21372
          #21375
          Assignees
          gewarren
          Labels
          🏁 Release: .NET 5Work items for the .NET 5 releasebreaking-changeIndicates a .NET Core breaking change
          Description
          @GrabYourPitchforks
          GrabYourPitchforks
          opened on Nov 6, 2020
          Breaking change: Improved String.LastIndexOf handling of empty values
          string.LastIndexOf and related APIs now return correct values when searching for a zero-length (or zero-length equivalent) substring within a larger string.
          Version introduced
          .NET 5.0
          Old behavior
          In .NET Framework and .NET Core, string.LastIndexOf and related APIs could return an incorrect value when the caller searches for a zero-length substring.
          Console.WriteLine("Hello".LastIndexOf(""));// prints '4' (incorrect)ReadOnlySpan<char>span="Hello";Console.WriteLine(span.LastIndexOf(""));// prints '0' (incorrect)
          New behavior
          Beginning with .NET 5.0, these APIs return the correct value for LastIndexOf.
          Console.WriteLine("Hello".LastIndexOf(""));// prints '5' (correct)ReadOnlySpan<char>span="Hello";Console.WriteLine(span.LastIndexOf(""));// prints '5' (correct)
          In these examples, 5 is the correct answer because "Hello".Substring(5) and "Hello".AsSpan().Slice(5) both produce an empty string, which is trivially equal to the empty substring being sought.
          Reason for change
          This change was part of an overall bug fixing effort around string handling for .NET 5. This also helps unify our behavior between Windows and non-Windows platforms. See dotnet/runtime#13383 and dotnet/runtime#13382 for more information.
          Recommended action
          Developers needn't take any action. The .NET 5.0 runtime provides the new behaviors automatically.
          There is no compatibility switch to restore the old behavior.
          Category
          • Core .NET libraries
          Affected APIs
          Issue metadata
          • Issue type: breaking-change
          Metadata
          Metadata
          Assignees
          Labels
          🏁 Release: .NET 5Work items for the .NET 5 releasebreaking-changeIndicates a .NET Core breaking change
          Type
          No type
          Projects
          No projects
            Milestone
            No milestone
            Relationships
            None yet
            Development
            No branches or pull requests
            Issue actions
            
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

            Skip to content
            Breaking change: Improved String.LastIndexOf handling of empty values #21372
            Closed
            #21375
            Closed
            Breaking change: Improved String.LastIndexOf handling of empty values#21372
            #21375
            Assignees
            gewarren
            Labels
            🏁 Release: .NET 5Work items for the .NET 5 releasebreaking-changeIndicates a .NET Core breaking change
            Description
            @GrabYourPitchforks
            GrabYourPitchforks
            opened on Nov 6, 2020
            Breaking change: Improved String.LastIndexOf handling of empty values
            string.LastIndexOf and related APIs now return correct values when searching for a zero-length (or zero-length equivalent) substring within a larger string.
            Version introduced
            .NET 5.0
            Old behavior
            In .NET Framework and .NET Core, string.LastIndexOf and related APIs could return an incorrect value when the caller searches for a zero-length substring.
            Console.WriteLine("Hello".LastIndexOf(""));// prints '4' (incorrect)ReadOnlySpan<char>span="Hello";Console.WriteLine(span.LastIndexOf(""));// prints '0' (incorrect)
            New behavior
            Beginning with .NET 5.0, these APIs return the correct value for LastIndexOf.
            Console.WriteLine("Hello".LastIndexOf(""));// prints '5' (correct)ReadOnlySpan<char>span="Hello";Console.WriteLine(span.LastIndexOf(""));// prints '5' (correct)
            In these examples, 5 is the correct answer because "Hello".Substring(5) and "Hello".AsSpan().Slice(5) both produce an empty string, which is trivially equal to the empty substring being sought.
            Reason for change
            This change was part of an overall bug fixing effort around string handling for .NET 5. This also helps unify our behavior between Windows and non-Windows platforms. See dotnet/runtime#13383 and dotnet/runtime#13382 for more information.
            Recommended action
            Developers needn't take any action. The .NET 5.0 runtime provides the new behaviors automatically.
            There is no compatibility switch to restore the old behavior.
            Category
            • Core .NET libraries
            Affected APIs
            Issue metadata
            • Issue type: breaking-change
            Metadata
            Metadata
            Assignees
            Labels
            🏁 Release: .NET 5Work items for the .NET 5 releasebreaking-changeIndicates a .NET Core breaking change
            Type
            No type
            Projects
            No projects
              Milestone
              No milestone
              Relationships
              None yet
              Development
              No branches or pull requests
              Issue actions
              
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

              Skip to content
              Breaking change: Improved String.LastIndexOf handling of empty values #21372
              Closed
              #21375
              Closed
              Breaking change: Improved String.LastIndexOf handling of empty values#21372
              #21375
              Assignees
              gewarren
              Labels
              🏁 Release: .NET 5Work items for the .NET 5 releasebreaking-changeIndicates a .NET Core breaking change
              Description
              @GrabYourPitchforks
              GrabYourPitchforks
              opened on Nov 6, 2020
              Breaking change: Improved String.LastIndexOf handling of empty values
              string.LastIndexOf and related APIs now return correct values when searching for a zero-length (or zero-length equivalent) substring within a larger string.
              Version introduced
              .NET 5.0
              Old behavior
              In .NET Framework and .NET Core, string.LastIndexOf and related APIs could return an incorrect value when the caller searches for a zero-length substring.
              Console.WriteLine("Hello".LastIndexOf(""));// prints '4' (incorrect)ReadOnlySpan<char>span="Hello";Console.WriteLine(span.LastIndexOf(""));// prints '0' (incorrect)
              New behavior
              Beginning with .NET 5.0, these APIs return the correct value for LastIndexOf.
              Console.WriteLine("Hello".LastIndexOf(""));// prints '5' (correct)ReadOnlySpan<char>span="Hello";Console.WriteLine(span.LastIndexOf(""));// prints '5' (correct)
              In these examples, 5 is the correct answer because "Hello".Substring(5) and "Hello".AsSpan().Slice(5) both produce an empty string, which is trivially equal to the empty substring being sought.
              Reason for change
              This change was part of an overall bug fixing effort around string handling for .NET 5. This also helps unify our behavior between Windows and non-Windows platforms. See dotnet/runtime#13383 and dotnet/runtime#13382 for more information.
              Recommended action
              Developers needn't take any action. The .NET 5.0 runtime provides the new behaviors automatically.
              There is no compatibility switch to restore the old behavior.
              Category
              • Core .NET libraries
              Affected APIs
              Issue metadata
              • Issue type: breaking-change
              Metadata
              Metadata
              Assignees
              Labels
              🏁 Release: .NET 5Work items for the .NET 5 releasebreaking-changeIndicates a .NET Core breaking change
              Type
              No type
              Projects
              No projects
                Milestone
                No milestone
                Relationships
                None yet
                Development
                No branches or pull requests
                Issue actions
                
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

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                Breaking change: Improved String.LastIndexOf handling of empty values #21372
                Closed
                #21375
                Closed
                Breaking change: Improved String.LastIndexOf handling of empty values#21372
                #21375
                Assignees
                gewarren
                Labels
                🏁 Release: .NET 5Work items for the .NET 5 releasebreaking-changeIndicates a .NET Core breaking change
                Description
                @GrabYourPitchforks
                GrabYourPitchforks
                opened on Nov 6, 2020
                Breaking change: Improved String.LastIndexOf handling of empty values
                string.LastIndexOf and related APIs now return correct values when searching for a zero-length (or zero-length equivalent) substring within a larger string.
                Version introduced
                .NET 5.0
                Old behavior
                In .NET Framework and .NET Core, string.LastIndexOf and related APIs could return an incorrect value when the caller searches for a zero-length substring.
                Console.WriteLine("Hello".LastIndexOf(""));// prints '4' (incorrect)ReadOnlySpan<char>span="Hello";Console.WriteLine(span.LastIndexOf(""));// prints '0' (incorrect)
                New behavior
                Beginning with .NET 5.0, these APIs return the correct value for LastIndexOf.
                Console.WriteLine("Hello".LastIndexOf(""));// prints '5' (correct)ReadOnlySpan<char>span="Hello";Console.WriteLine(span.LastIndexOf(""));// prints '5' (correct)
                In these examples, 5 is the correct answer because "Hello".Substring(5) and "Hello".AsSpan().Slice(5) both produce an empty string, which is trivially equal to the empty substring being sought.
                Reason for change
                This change was part of an overall bug fixing effort around string handling for .NET 5. This also helps unify our behavior between Windows and non-Windows platforms. See dotnet/runtime#13383 and dotnet/runtime#13382 for more information.
                Recommended action
                Developers needn't take any action. The .NET 5.0 runtime provides the new behaviors automatically.
                There is no compatibility switch to restore the old behavior.
                Category
                • Core .NET libraries
                Affected APIs
                Issue metadata
                • Issue type: breaking-change
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                🏁 Release: .NET 5Work items for the .NET 5 releasebreaking-changeIndicates a .NET Core breaking change
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