Enable nullability, round 3 of x

src/Markdig/Extensions/Abbreviations/AbbreviationHelper.cs

@@ -2,6 +2,8 @@
 // This file is licensed under the BSD-Clause 2 license. 
 // See the license.txt file in the project root for more information.
 
+#nullable enable
+
 using System.Collections.Generic;
 using Markdig.Helpers;
 using Markdig.Syntax;
@@ -22,20 +24,20 @@ public static bool HasAbbreviations(this MarkdownDocument document)
 
  public static void AddAbbreviation(this MarkdownDocument document, string label, Abbreviation abbr)
  {
- if (document == null) ThrowHelper.ArgumentNullException(nameof(document));
- if (label == null) ThrowHelper.ArgumentNullException_label();
- if (abbr == null) ThrowHelper.ArgumentNullException(nameof(abbr));
+ if (document is null) ThrowHelper.ArgumentNullException(nameof(document));
+ if (label is null) ThrowHelper.ArgumentNullException_label();
+ if (abbr is null) ThrowHelper.ArgumentNullException(nameof(abbr));
 
  var map = document.GetAbbreviations();
- if (map == null)
+ if (map is null)
  {
  map = new Dictionary<string, Abbreviation>();
  document.SetData(DocumentKey, map);
  }
  map[label] = abbr;
  }
 
- public static Dictionary<string, Abbreviation> GetAbbreviations(this MarkdownDocument document)
+ public static Dictionary<string, Abbreviation>? GetAbbreviations(this MarkdownDocument document)
  {
  return document.GetData(DocumentKey) as Dictionary<string, Abbreviation>;
  }

src/Markdig/Extensions/Abbreviations/AbbreviationParser.cs

@@ -75,7 +75,7 @@ public override BlockState TryOpen(BlockProcessor processor)
  return BlockState.BreakDiscard;
  }
 
- private void DocumentOnProcessInlinesBegin(InlineProcessor inlineProcessor, Inline inline)
+ private void DocumentOnProcessInlinesBegin(InlineProcessor inlineProcessor, Inline? inline)
  {
  inlineProcessor.Document.ProcessInlinesBegin -= DocumentOnProcessInlinesBegin;
 

src/Markdig/Extensions/AutoIdentifiers/AutoIdentifierExtension.cs

@@ -2,6 +2,8 @@
 // This file is licensed under the BSD-Clause 2 license.
 // See the license.txt file in the project root for more information.
 
+#nullable enable
+
 using System.Collections.Generic;
 using System.IO;
 using Markdig.Helpers;
@@ -95,11 +97,11 @@ private void HeadingBlockParser_Closed(BlockProcessor processor, Block block)
  headingBlock.ProcessInlinesEnd += HeadingBlock_ProcessInlinesEnd;
  }
 
- private void DocumentOnProcessInlinesBegin(InlineProcessor processor, Inline inline)
+ private void DocumentOnProcessInlinesBegin(InlineProcessor processor, Inline? inline)
  {
  var doc = processor.Document;
  doc.ProcessInlinesBegin -= DocumentOnProcessInlinesBegin;
- var dictionary = (Dictionary<string, HeadingLinkReferenceDefinition>)doc.GetData(this);
+ var dictionary = (Dictionary<string, HeadingLinkReferenceDefinition>)doc.GetData(this)!;
  foreach (var keyPair in dictionary)
  {
  // Here we make sure that auto-identifiers will not override an existing link definition
@@ -118,7 +120,7 @@ private void DocumentOnProcessInlinesBegin(InlineProcessor processor, Inline inl
  /// Callback when there is a reference to found to a heading.
  /// Note that reference are only working if they are declared after.
  /// </summary>
- private Inline CreateLinkInlineForHeading(InlineProcessor inlineState, LinkReferenceDefinition linkRef, Inline child)
+ private Inline CreateLinkInlineForHeading(InlineProcessor inlineState, LinkReferenceDefinition linkRef, Inline? child)
  {
  var headingRef = (HeadingLinkReferenceDefinition) linkRef;
  return new LinkInline()
@@ -135,23 +137,23 @@ private Inline CreateLinkInlineForHeading(InlineProcessor inlineState, LinkRefer
  /// </summary>
  /// <param name="processor">The processor.</param>
  /// <param name="inline">The inline.</param>
- private void HeadingBlock_ProcessInlinesEnd(InlineProcessor processor, Inline inline)
+ private void HeadingBlock_ProcessInlinesEnd(InlineProcessor processor, Inline? inline)
  {
  var identifiers = processor.Document.GetData(AutoIdentifierKey) as HashSet<string>;
- if (identifiers == null)
+ if (identifiers is null)
  {
  identifiers = new HashSet<string>();
  processor.Document.SetData(AutoIdentifierKey, identifiers);
  }
 
- var headingBlock = (HeadingBlock) processor.Block;
- if (headingBlock.Inline == null)
+ var headingBlock = (HeadingBlock) processor.Block!;
+ if (headingBlock.Inline is null)
  {
  return;
  }
 
  // If id is already set, don't try to modify it
- var attributes = processor.Block.GetAttributes();
+ var attributes = processor.Block!.GetAttributes();
  if (attributes.Id != null)
  {
  return;
@@ -161,7 +163,7 @@ private void HeadingBlock_ProcessInlinesEnd(InlineProcessor processor, Inline in
  var stripRenderer = rendererCache.Get();
 
  stripRenderer.Render(headingBlock.Inline);
- var headingText = stripRenderer.Writer.ToString();
+ var headingText = stripRenderer.Writer.ToString()!;
  rendererCache.Release(stripRenderer);
 
  // Urilize the link

src/Markdig/Extensions/CustomContainers/CustomContainer.cs

@@ -2,6 +2,8 @@
 // This file is licensed under the BSD-Clause 2 license. 
 // See the license.txt file in the project root for more information.
 
+#nullable enable
+
 using Markdig.Helpers;
 using Markdig.Parsers;
 using Markdig.Syntax;
@@ -33,7 +35,7 @@ public CustomContainer(BlockParser parser) : base(parser)
  public StringSlice TriviaAfterFencedChar { get; set; }
 
  /// <inheritdoc />
- public string Info { get; set; }
+ public string? Info { get; set; }
 
  /// <inheritdoc />
  public StringSlice UnescapedInfo { get; set; }
@@ -42,7 +44,7 @@ public CustomContainer(BlockParser parser) : base(parser)
  public StringSlice TriviaAfterInfo { get; set; }
 
  /// <inheritdoc />
- public string Arguments { get; set; }
+ public string? Arguments { get; set; }
 
  /// <inheritdoc />
  public StringSlice UnescapedArguments { get; set; }

src/Markdig/Extensions/DefinitionLists/DefinitionListParser.cs

@@ -2,6 +2,8 @@
 // This file is licensed under the BSD-Clause 2 license. 
 // See the license.txt file in the project root for more information.
 
+#nullable enable
+
 using System;
 using Markdig.Parsers;
 using Markdig.Syntax;
@@ -25,7 +27,7 @@ public DefinitionListParser()
  public override BlockState TryOpen(BlockProcessor processor)
  {
  var paragraphBlock = processor.LastBlock as ParagraphBlock;
- if (processor.IsCodeIndent || paragraphBlock == null || paragraphBlock.LastLine - processor.LineIndex > 1)
+ if (processor.IsCodeIndent || paragraphBlock is null || paragraphBlock.LastLine - processor.LineIndex > 1)
  {
  return BlockState.None;
  }
@@ -50,7 +52,7 @@ public override BlockState TryOpen(BlockProcessor processor)
  processor.GoToColumn(column + 4);
  }
 
- var previousParent = paragraphBlock.Parent;
+ var previousParent = paragraphBlock.Parent!;
  var currentDefinitionList = GetCurrentDefinitionList(paragraphBlock, previousParent);
 
  processor.Discard(paragraphBlock);
@@ -102,7 +104,7 @@ public override BlockState TryOpen(BlockProcessor processor)
  return BlockState.Continue;
  }
 
- private static DefinitionList GetCurrentDefinitionList(ParagraphBlock paragraphBlock, ContainerBlock previousParent)
+ private static DefinitionList? GetCurrentDefinitionList(ParagraphBlock paragraphBlock, ContainerBlock previousParent)
  {
  var index = previousParent.IndexOf(paragraphBlock) - 1;
  if (index < 0) return null;
@@ -124,11 +126,11 @@ public override BlockState TryContinue(BlockProcessor processor, Block block)
  return BlockState.Continue;
  }
 
- var list = (DefinitionList)definitionItem.Parent;
+ var list = (DefinitionList)definitionItem.Parent!;
  var lastBlankLine = definitionItem.LastChild as BlankLineBlock;
 
  // Check if we have another definition list
- if (Array.IndexOf(OpeningCharacters, processor.CurrentChar) >= 0)
+ if (Array.IndexOf(OpeningCharacters!, processor.CurrentChar) >= 0)
  {
  var startPosition = processor.Start;
  var column = processor.ColumnBeforeIndent;
@@ -145,7 +147,7 @@ public override BlockState TryContinue(BlockProcessor processor, Block block)
  definitionItem.RemoveAt(definitionItem.Count - 1);
  }
 
- list.Span.End = list.LastChild.Span.End;
+ list.Span.End = list.LastChild!.Span.End;
  return BlockState.None;
  }
 
@@ -179,7 +181,7 @@ public override BlockState TryContinue(BlockProcessor processor, Block block)
  }
 
  var paragraphBlock = definitionItem.LastChild as ParagraphBlock;
- if (lastBlankLine == null && paragraphBlock != null)
+ if (lastBlankLine is null && paragraphBlock != null)
  {
  return BlockState.Continue;
  }
@@ -190,7 +192,7 @@ public override BlockState TryContinue(BlockProcessor processor, Block block)
  definitionItem.RemoveAt(definitionItem.Count - 1);
  }
 
- list.Span.End = list.LastChild.Span.End;
+ list.Span.End = list.LastChild!.Span.End;
  return BlockState.Break;
  }
  }

src/Markdig/Extensions/Emoji/EmojiMapping.cs

@@ -2,6 +2,8 @@
 // This file is licensed under the BSD-Clause 2 license. 
 // See the license.txt file in the project root for more information.
 
+#nullable enable
+
 using System.Collections.Generic;
 using Markdig.Helpers;
 
@@ -1778,7 +1780,7 @@ public EmojiMapping(IDictionary<string, string> shortcodeToUnicode, IDictionary<
  if (string.IsNullOrEmpty(smiley.Key) || string.IsNullOrEmpty(smiley.Value))
  ThrowHelper.ArgumentException("The dictionaries cannot contain null or empty keys/values", nameof(smileyToShortcode));
 
- if (!shortcodeToUnicode.TryGetValue(smiley.Value, out string unicode))
+ if (!shortcodeToUnicode.TryGetValue(smiley.Value, out string? unicode))
  ThrowHelper.ArgumentException(string.Format("Invalid smiley target: {0} is not present in the emoji shortcodes dictionary", smiley.Value));
 
  firstChars.Add(smiley.Key[0]);

src/Markdig/Extensions/Footnotes/FootnoteParser.cs

@@ -2,6 +2,8 @@
 // This file is licensed under the BSD-Clause 2 license. 
 // See the license.txt file in the project root for more information.
 
+#nullable enable
+
 using Markdig.Helpers;
 using Markdig.Parsers;
 using Markdig.Syntax;
@@ -41,7 +43,7 @@ private BlockState TryOpen(BlockProcessor processor, bool isContinue)
 
  var saved = processor.Column;
  int start = processor.Start;
- if (!LinkHelper.TryParseLabel(ref processor.Line, false, out string label, out SourceSpan labelSpan) || !label.StartsWith("^") || processor.CurrentChar != ':')
+ if (!LinkHelper.TryParseLabel(ref processor.Line, false, out string? label, out SourceSpan labelSpan) || !label.StartsWith("^") || processor.CurrentChar != ':')
  {
  processor.GoToColumn(saved);
  return BlockState.None;
@@ -130,12 +132,12 @@ public override BlockState TryContinue(BlockProcessor processor, Block block)
  /// </summary>
  /// <param name="state">The processor.</param>
  /// <param name="inline">The inline.</param>
- private void Document_ProcessInlinesEnd(InlineProcessor state, Inline inline)
+ private void Document_ProcessInlinesEnd(InlineProcessor state, Inline? inline)
  {
  // Unregister
  state.Document.ProcessInlinesEnd -= Document_ProcessInlinesEnd;
 
- var footnotes = ((FootnoteGroup)state.Document.GetData(DocumentKey));
+ var footnotes = (FootnoteGroup)state.Document.GetData(DocumentKey)!;
  // Remove the footnotes from the document and readd them at the end
  state.Document.Remove(footnotes);
  state.Document.Add(footnotes);
@@ -166,7 +168,7 @@ private void Document_ProcessInlinesEnd(InlineProcessor state, Inline inline)
 
  // Insert all footnote backlinks
  var paragraphBlock = footnote.LastChild as ParagraphBlock;
- if (paragraphBlock == null)
+ if (paragraphBlock is null)
  {
  paragraphBlock = new ParagraphBlock();
  footnote.Add(paragraphBlock);
@@ -191,12 +193,12 @@ private void Document_ProcessInlinesEnd(InlineProcessor state, Inline inline)
  }
  }
 
- private static Inline CreateLinkToFootnote(InlineProcessor state, LinkReferenceDefinition linkRef, Inline child)
+ private static Inline CreateLinkToFootnote(InlineProcessor state, LinkReferenceDefinition linkRef, Inline? child)
  {
  var footnote = ((FootnoteLinkReferenceDefinition)linkRef).Footnote;
  if (footnote.Order < 0)
  {
- var footnotes = (FootnoteGroup)state.Document.GetData(DocumentKey);
+ var footnotes = (FootnoteGroup)state.Document.GetData(DocumentKey)!;
  footnotes.CurrentOrder++;
  footnote.Order = footnotes.CurrentOrder;
  }

src/Markdig/Extensions/GenericAttributes/GenericAttributesParser.cs

@@ -45,7 +45,7 @@ public override bool Match(InlineProcessor processor, ref StringSlice slice)
  }
  }
  }
- var objectToAttach = inline == null || inline == processor.Root ? (MarkdownObject) processor.Block : inline;
+ var objectToAttach = inline is null || inline == processor.Root ? (MarkdownObject)processor.Block : inline;
 
  // If the current block is a Paragraph, but only the HtmlAttributes is used,
  // Try to attach the attributes to the following block

src/Markdig/Extensions/MediaLinks/MediaLinkExtension.cs

@@ -2,6 +2,8 @@
 // This file is licensed under the BSD-Clause 2 license.
 // See the license.txt file in the project root for more information.
 
+#nullable enable
+
 using System;
 using Markdig.Renderers;
 using Markdig.Renderers.Html;
@@ -20,7 +22,7 @@ public MediaLinkExtension() : this(new MediaOptions())
  {
  }
 
- public MediaLinkExtension(MediaOptions options)
+ public MediaLinkExtension(MediaOptions? options)
  {
  Options = options ?? new MediaOptions();
  }
@@ -53,7 +55,7 @@ private bool TryLinkInlineRenderer(HtmlRenderer renderer, LinkInline linkInline)
 
  bool isSchemaRelative = false;
  // Only process absolute Uri
- if (!Uri.TryCreate(linkInline.Url, UriKind.RelativeOrAbsolute, out Uri uri) || !uri.IsAbsoluteUri)
+ if (!Uri.TryCreate(linkInline.Url, UriKind.RelativeOrAbsolute, out Uri? uri) || !uri.IsAbsoluteUri)
  {
  // see https://tools.ietf.org/html/rfc3986#section-4.2
  // since relative uri doesn't support many properties, "http" is used as a placeholder here.
@@ -98,7 +100,7 @@ private bool TryGuessAudioVideoFile(Uri uri, bool isSchemaRelative, HtmlRenderer
  // Otherwise try to detect if we have an audio/video from the file extension
  var lastDot = path.LastIndexOf('.');
  if (lastDot >= 0 &&
- Options.ExtensionToMimeType.TryGetValue(path.Substring(lastDot), out string mimeType))
+ Options.ExtensionToMimeType.TryGetValue(path.Substring(lastDot), out string? mimeType))
  {
  var htmlAttributes = GetHtmlAttributes(linkInline);
  var isAudio = mimeType.StartsWith("audio");
@@ -126,9 +128,8 @@ private bool TryGuessAudioVideoFile(Uri uri, bool isSchemaRelative, HtmlRenderer
 
  private bool TryRenderIframeFromKnownProviders(Uri uri, bool isSchemaRelative, HtmlRenderer renderer, LinkInline linkInline)
  {
-
- IHostProvider foundProvider = null;
- string iframeUrl = null;
+ IHostProvider? foundProvider = null;
+ string? iframeUrl = null;
  foreach (var provider in Options.Hosts)
  {
  if (!provider.TryHandle(uri, isSchemaRelative, out iframeUrl))
@@ -137,7 +138,7 @@ private bool TryRenderIframeFromKnownProviders(Uri uri, bool isSchemaRelative, H
  break;
  }
 
- if (foundProvider == null)
+ if (foundProvider is null)
  {
  return false;
  }
@@ -156,8 +157,8 @@ private bool TryRenderIframeFromKnownProviders(Uri uri, bool isSchemaRelative, H
  if (!string.IsNullOrEmpty(Options.Class))
  htmlAttributes.AddClass(Options.Class);
 
- if (!string.IsNullOrEmpty(foundProvider.Class))
- htmlAttributes.AddClass(foundProvider.Class);
+ if (foundProvider.Class is { Length: > 0 } className)
+ htmlAttributes.AddClass(className);
 
  htmlAttributes.AddPropertyIfNotExist("frameborder", "0");
  if (foundProvider.AllowFullScreen)