Bug? Inline HTML is converted to wrong result #359

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claunia · 2026-01-29T14:34:50Z

claunia commented

2026-01-29 14:34:50 +00:00

Originally created by @Dixin on GitHub (Apr 18, 2020).

I work with a complicated environment, where we need to render a lot of documents with MD and HTML mixed. Some HTML <pre> blocks are converted to wrong result.

Problem

Take the following document as example:

## MD Heading

MD Paragraph

<p>HTML Paragraph</p>
<pre class="code"><span style="color: blue;">public partial class </span><span style="color: rgb(43, 145, 175);">AdventureWorks </span><span style="color: black;">: </span><span style="color: rgb(43, 145, 175);">DbContext
</span><span style="color: black;">{
    </span><span style="color: blue;">protected override void </span><span style="color: black;">OnModelCreating(</span><span style="color: rgb(43, 145, 175);">DbModelBuilder </span><span style="color: black;">modelBuilder)
    {
        </span><span style="color: blue;">base</span><span style="color: black;">.OnModelCreating(modelBuilder);

        </span><span style="color: green;">// Add functions on AdventureWorks to entity model.
        </span><span style="color: black;">modelBuilder.Conventions.Add(</span><span style="color: blue;">new </span><span style="color: rgb(43, 145, 175);">FunctionConvention</span><span style="color: black;">&lt;</span><span style="color: rgb(43, 145, 175);">AdventureWorks</span><span style="color: black;">&gt;());

        </span><span style="color: green;">// Add all complex types used by functions.
        </span><span style="color: black;">modelBuilder.ComplexType&lt;</span><span style="color: rgb(43, 145, 175);">ContactInformation</span><span style="color: black;">&gt;();
        modelBuilder.ComplexType&lt;</span><span style="color: rgb(43, 145, 175);">ManagerEmployee</span><span style="color: black;">&gt;();
        </span><span style="color: green;">// ...
    </span><span style="color: black;">}
}</span></pre>

it includes <pre> block, which is correctly rendered as:

(See: https://jsfiddle.net/dixin/0dj2b81x/)

Then I tried to process it with MarkDig:

static void Main()
{
    MarkdownPipelineBuilder builder = new MarkdownPipelineBuilder().UseAdvancedExtensions();
    MarkdownPipeline pipeline = builder.Build();
    string html = Markdown.ToHtml(File.ReadAllText(@"d:\md.txt"), pipeline);
    File.WriteAllText(@"d:\html.txt", html);
}

The HTML result is messed up:

<h2 id="md-heading">MD Heading</h2>
<p>MD Paragraph</p>
<p>HTML Paragraph</p>
<pre class="code"><span style="color: blue;">public partial class </span><span style="color: rgb(43, 145, 175);">AdventureWorks </span><span style="color: black;">: </span><span style="color: rgb(43, 145, 175);">DbContext
</span><span style="color: black;">{
    </span><span style="color: blue;">protected override void </span><span style="color: black;">OnModelCreating(</span><span style="color: rgb(43, 145, 175);">DbModelBuilder </span><span style="color: black;">modelBuilder)
    {
        </span><span style="color: blue;">base</span><span style="color: black;">.OnModelCreating(modelBuilder);
<pre><code>    &lt;/span&gt;&lt;span style=&quot;color: green;&quot;&gt;// Add functions on AdventureWorks to entity model.
    &lt;/span&gt;&lt;span style=&quot;color: black;&quot;&gt;modelBuilder.Conventions.Add(&lt;/span&gt;&lt;span style=&quot;color: blue;&quot;&gt;new &lt;/span&gt;&lt;span style=&quot;color: rgb(43, 145, 175);&quot;&gt;FunctionConvention&lt;/span&gt;&lt;span style=&quot;color: black;&quot;&gt;&amp;lt;&lt;/span&gt;&lt;span style=&quot;color: rgb(43, 145, 175);&quot;&gt;AdventureWorks&lt;/span&gt;&lt;span style=&quot;color: black;&quot;&gt;&amp;gt;());

    &lt;/span&gt;&lt;span style=&quot;color: green;&quot;&gt;// Add all complex types used by functions.
    &lt;/span&gt;&lt;span style=&quot;color: black;&quot;&gt;modelBuilder.ComplexType&amp;lt;&lt;/span&gt;&lt;span style=&quot;color: rgb(43, 145, 175);&quot;&gt;ContactInformation&lt;/span&gt;&lt;span style=&quot;color: black;&quot;&gt;&amp;gt;();
    modelBuilder.ComplexType&amp;lt;&lt;/span&gt;&lt;span style=&quot;color: rgb(43, 145, 175);&quot;&gt;ManagerEmployee&lt;/span&gt;&lt;span style=&quot;color: black;&quot;&gt;&amp;gt;();
    &lt;/span&gt;&lt;span style=&quot;color: green;&quot;&gt;// ...
&lt;/span&gt;&lt;span style=&quot;color: black;&quot;&gt;}
</code></pre>
<p>}</span></pre></p>

So the document becomes not readable:

(See https://jsfiddle.net/dixin/6j7yLx85/)

Partial solution

I found #348, and used its code:

builder.BlockParsers.TryRemove<IndentedCodeBlockParser>();

Now the HTML result gets better:

<h2 id="md-heading">MD Heading</h2>
<p>MD Paragraph</p>
<p>HTML Paragraph</p>
<pre class="code"><span style="color: blue;">public partial class </span><span style="color: rgb(43, 145, 175);">AdventureWorks </span><span style="color: black;">: </span><span style="color: rgb(43, 145, 175);">DbContext
</span><span style="color: black;">{
    </span><span style="color: blue;">protected override void </span><span style="color: black;">OnModelCreating(</span><span style="color: rgb(43, 145, 175);">DbModelBuilder </span><span style="color: black;">modelBuilder)
    {
        </span><span style="color: blue;">base</span><span style="color: black;">.OnModelCreating(modelBuilder);
<p></span><span style="color: green;">// Add functions on AdventureWorks to entity model.
</span><span style="color: black;">modelBuilder.Conventions.Add(</span><span style="color: blue;">new </span><span style="color: rgb(43, 145, 175);">FunctionConvention</span><span style="color: black;">&lt;</span><span style="color: rgb(43, 145, 175);">AdventureWorks</span><span style="color: black;">&gt;());</p>
<p></span><span style="color: green;">// Add all complex types used by functions.
</span><span style="color: black;">modelBuilder.ComplexType&lt;</span><span style="color: rgb(43, 145, 175);">ContactInformation</span><span style="color: black;">&gt;();
modelBuilder.ComplexType&lt;</span><span style="color: rgb(43, 145, 175);">ManagerEmployee</span><span style="color: black;">&gt;();
</span><span style="color: green;">// ...
</span><span style="color: black;">}
}</span></pre></p>

The document becomes a little more readable:

(See: https://jsfiddle.net/dixin/tzkphu2m/1/)

It still has problems:

Inside <pre> block, it removes the intentional blank line,
It adds  inside <pre> and outside </pre>
It removes some of the indentation inside <pre> block.

Questions

What should I do to render the above example document correctly?

Regarding the result HTML has wrong indent and even wrong format (<pre>......</pre>), is this a bug?

Thank you for help.

Originally created by @Dixin on GitHub (Apr 18, 2020). I work with a complicated environment, where we need to render a lot of documents with MD and HTML mixed. Some HTML `<pre>` blocks are converted to wrong result. ## Problem Take the following document as example: ```md ## MD Heading MD Paragraph HTML Paragraph <pre class="code">public partial class AdventureWorks : DbContext { protected override void OnModelCreating(DbModelBuilder modelBuilder) { base.OnModelCreating(modelBuilder); // Add functions on AdventureWorks to entity model. modelBuilder.Conventions.Add(new FunctionConvention<AdventureWorks>()); // Add all complex types used by functions. modelBuilder.ComplexType<ContactInformation>(); modelBuilder.ComplexType<ManagerEmployee>(); // ... } }</pre> ``` it includes `<pre>` block, which is correctly rendered as: ![image](https://user-images.githubusercontent.com/1563770/79622320-94b7a080-80cb-11ea-9c6c-e0d780033df5.png) (See: https://jsfiddle.net/dixin/0dj2b81x/) Then I tried to process it with MarkDig: ```cs static void Main() { MarkdownPipelineBuilder builder = new MarkdownPipelineBuilder().UseAdvancedExtensions(); MarkdownPipeline pipeline = builder.Build(); string html = Markdown.ToHtml(File.ReadAllText(@"d:\md.txt"), pipeline); File.WriteAllText(@"d:\html.txt", html); } ``` The HTML result is messed up: ```html <h2 id="md-heading">MD Heading</h2> MD Paragraph HTML Paragraph <pre class="code">public partial class AdventureWorks : DbContext { protected override void OnModelCreating(DbModelBuilder modelBuilder) { base.OnModelCreating(modelBuilder); <pre><code> // Add functions on AdventureWorks to entity model. modelBuilder.Conventions.Add(new FunctionConvention&lt;AdventureWorks&gt;()); // Add all complex types used by functions. modelBuilder.ComplexType&lt;ContactInformation&gt;(); modelBuilder.ComplexType&lt;ManagerEmployee&gt;(); // ... } </code></pre> }</pre> ``` So the document becomes not readable: ![image](https://user-images.githubusercontent.com/1563770/79622559-9df53d00-80cc-11ea-823d-382c3182470c.png) (See https://jsfiddle.net/dixin/6j7yLx85/) ## Partial solution I found #348, and used its code: ```cs builder.BlockParsers.TryRemove<IndentedCodeBlockParser>(); ``` Now the HTML result gets better: ```html <h2 id="md-heading">MD Heading</h2> MD Paragraph HTML Paragraph <pre class="code">public partial class AdventureWorks : DbContext { protected override void OnModelCreating(DbModelBuilder modelBuilder) { base.OnModelCreating(modelBuilder); // Add functions on AdventureWorks to entity model. modelBuilder.Conventions.Add(new FunctionConvention<AdventureWorks>()); // Add all complex types used by functions. modelBuilder.ComplexType<ContactInformation>(); modelBuilder.ComplexType<ManagerEmployee>(); // ... } }</pre> ``` The document becomes a little more readable: ![image](https://user-images.githubusercontent.com/1563770/79623071-2e348180-80cf-11ea-8e1b-3b3f5cb8e530.png) (See: https://jsfiddle.net/dixin/tzkphu2m/1/) It still has problems: - Inside `<pre>` block, it removes the intentional blank line, - It adds `` inside `<pre>` and outside `</pre>` - It removes some of the indentation inside `<pre>` block. ## Questions What should I do to render the above example document correctly? Regarding the result HTML has wrong indent and even wrong format (`<pre>......</pre>`), is this a bug? Thank you for help.

claunia commented

2026-01-29 14:34:51 +00:00

@MihaZupan commented on GitHub (Apr 18, 2020):

It's unfortunate every line is in a separate pre region.

The output without the IndentedCodeBlockParser does seem a bit weird, I'll look into that.

@MihaZupan commented on GitHub (Apr 18, 2020): It's unfortunate every line is in a separate `pre` region. The output without the `IndentedCodeBlockParser` does seem a bit weird, I'll look into that.

claunia commented

2026-01-29 14:34:52 +00:00

@Dixin commented on GitHub (Apr 20, 2020):

Thank you @MihaZupan for looking into this.

It's unfortunate every line is in a separate pre region.

What should I do if I want to keep everything unchanged between <pre> and </pre>?

@Dixin commented on GitHub (Apr 20, 2020): Thank you @MihaZupan for looking into this. > It's unfortunate every line is in a separate pre region. What should I do if I want to keep everything unchanged between `<pre>` and `</pre>`?

claunia commented

2026-01-29 14:34:53 +00:00

@MihaZupan commented on GitHub (Jul 11, 2020):

I haven't looked into how we would correct/change the behavior here, but it looks like it's caused by how we handle paragraph continuations.

As a workaround rn, you can add an extra line after the paragraph (note the empty line after HTML Paragrap):

## MD Heading

MD Paragraph

<p>HTML Paragraph</p>

<pre class="code"><span style="color: blue;">public partial class </span><span style="color: rgb(43, 145, 175);">AdventureWorks </span><span style="color: black;">: </span><span style="color: rgb(43, 145, 175);">DbContext
</span><span style="color: black;">{
    </span><span style="color: blue;">protected override void </span><span style="color: black;">OnModelCreating(</span><span style="color: rgb(43, 145, 175);">DbModelBuilder </span><span style="color: black;">modelBuilder)
    {

...

This will render properly.

@MihaZupan commented on GitHub (Jul 11, 2020): I haven't looked into how we would correct/change the behavior here, but it looks like it's caused by how we handle paragraph continuations. As a workaround rn, you can add an extra line after the paragraph (note the empty line after `HTML Paragrap`): ```html ## MD Heading MD Paragraph HTML Paragraph <pre class="code">public partial class AdventureWorks : DbContext { protected override void OnModelCreating(DbModelBuilder modelBuilder) { ... ``` This will render properly. ![image](https://user-images.githubusercontent.com/25307628/87235292-e32ebf80-c3da-11ea-89f4-197011394ad4.png)

claunia commented

2026-01-29 14:34:54 +00:00

@Dixin commented on GitHub (Jul 12, 2020):

@MihaZupan Thank you for the reply. I have identified the problem and have a code fix. I also identified the source of this problem comes deeper from common markdown spec. Later I will file an issue for markdig and an issue for common markdown, with all details and code fix.

@Dixin commented on GitHub (Jul 12, 2020): @MihaZupan Thank you for the reply. I have identified the problem and have a code fix. I also identified the source of this problem comes deeper from common markdown spec. Later I will file an issue for markdig and an issue for common markdown, with all details and code fix.

claunia commented

2026-01-29 14:34:55 +00:00

@MihaZupan commented on GitHub (Jul 12, 2020):

Thanks!

@MihaZupan commented on GitHub (Jul 12, 2020): Thanks!

claunia referenced this issue

2026-01-29 14:47:56 +00:00

[PR #359] [CLOSED] [WIP] Optimize abbreviation parser re-entry #969

claunia referenced this issue

2026-01-29 14:48:01 +00:00

[PR #359] [WIP] Optimize abbreviation parser re-entry #974

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