Fix blockquote ordered list parsing (#887)

src/Markdig.Tests/MiscTests.cs

@@ -481,6 +481,61 @@ A tip inside a note</p>
         TestParser.TestSpec(input, expected, new MarkdownPipelineBuilder().UseAlertBlocks(allowNestedAlerts: true).Build());
     }
 
+    [Test]
+    public void TestIssue887ListAfterNestedBlockQuote()
+    {
+        var input = @"> >* _Unordered 1_ QL2 level 1 no space sep
+> >  Continued 1
+> > * Unordered 2 level 1
+> > 1. **Ordered 1** QL2 level 1
+> >    Continued 1
+> > > Not continued QL3
+> > 2. Ordered 2 QL2 level 1
+> > Continued 2a
+> >
+> >    Continued 2b
+> >
+> >    Continued 2c
+> >
+> >    3. Ordered 3 QL2 level 2
+> >       Continued 3a
+> >
+> >       Continued 3b
+";
+
+        var expected = @"<blockquote>
+<blockquote>
+<ul>
+<li><em>Unordered 1</em> QL2 level 1 no space sep
+Continued 1</li>
+<li>Unordered 2 level 1</li>
+</ul>
+<ol>
+<li><strong>Ordered 1</strong> QL2 level 1
+Continued 1</li>
+</ol>
+<blockquote>
+<p>Not continued QL3</p>
+</blockquote>
+<ol start=""2"">
+<li><p>Ordered 2 QL2 level 1
+Continued 2a</p>
+<p>Continued 2b</p>
+<p>Continued 2c</p>
+<ol start=""3"">
+<li><p>Ordered 3 QL2 level 2
+Continued 3a</p>
+<p>Continued 3b</p>
+</li>
+</ol>
+</li>
+</ol>
+</blockquote>
+</blockquote>";
+
+        TestParser.TestSpec(input, expected);
+    }
+
     [Test]
     public void TestIssue845ListItemBlankLine()
     {

src/Markdig/Parsers/BlockProcessor.cs

@@ -152,6 +152,11 @@ public class BlockProcessor
     /// </summary>
     public bool IsLazy { get; private set; }
 
+    /// <summary>
+    /// Gets a value indicating whether the current line failed to continue one of the open containers.
+    /// </summary>
+    internal bool HasUnmatchedBlocks { get; private set; }
+
     /// <summary>
     /// Gets the current stack of <see cref="Block"/> being processed.
     /// </summary>
@@ -689,6 +694,7 @@ public class BlockProcessor
     private void TryContinueBlocks()
     {
         IsLazy = false;
+        HasUnmatchedBlocks = false;
 
         // Set all blocks non opened.
         // They will be marked as open in the following loop
@@ -723,6 +729,7 @@ public class BlockProcessor
 
             if (result == BlockState.None)
             {
+                HasUnmatchedBlocks = true;
                 break;
             }
 
@@ -1049,6 +1056,7 @@ public class BlockProcessor
         SkipFirstUnwindSpace = false;
         ContinueProcessingLine = false;
         IsLazy = false;
+        HasUnmatchedBlocks = false;
 
         currentStackIndex = 0;
         originalLineStart = 0;

src/Markdig/Parsers/ListBlockParser.cs

@@ -275,8 +275,13 @@ public class ListBlockParser : BlockParser
         block ??= state.LastBlock;
         if (block is not null && block.IsParagraphBlock)
         {
+            bool isOrderedListInterruptingParagraph = !state.HasUnmatchedBlocks &&
+                state.IsOpen(block) &&
+                listInfo.BulletType == '1' &&
+                listInfo.OrderedStart is not "1";
+
             if (state.IsBlankLine ||
-                state.IsOpen(block) && listInfo.BulletType == '1' && listInfo.OrderedStart is not "1")
+                isOrderedListInterruptingParagraph)
             {
                 state.GoToColumn(initColumn);
                 state.TriviaStart = savedTriviaStart; // restore changed TriviaStart state