Rule - MD048

Property	Value
Aliases	md048, code-fence-style
Autofix Available	Yes
Enabled By Default	Yes

Summary

Enforce a consistent code fence style throughout the document.

Reasoning

Readability

Consistent fence characters improve readability and enable organizations to enforce uniform code block formatting standards across documents.

Examples

Failure Scenarios

This rule triggers when there is inconsistent use of fence characters for Fenced Code Blocks:

```Python
a=b
```

~~~Python
a=b
~~~

```Python
c=3
```

Explanation: The document uses backticks (```) for the first and third code blocks, but tildes (~~~) for the second code block. This violates the rule because the fence style is not consistent throughout the document under the default consistent style — the first Fenced Code Block (backticks) sets the expectation, and the second block (tildes) breaks it.

Unlike the previous example, this scenario demonstrates a failure when the style configuration is set to backtick, but tildes are used.

~~~Python
a=b
~~~

Explanation: The code block uses tildes (~~~) as fence characters. This violates the rule because the configuration specifies that only backticks (```) should be used when style is set to backtick.

Unlike the previous example, this scenario demonstrates a failure when the style configuration is set to tilde, but backticks are used.

```Python
a=b
```

Explanation: The code block uses backticks (```) as fence characters. This violates the rule because the configuration specifies that only tildes (~~~) should be used when style is set to tilde.

Correct Scenarios

This rule does not trigger when the fence character for Fenced Code Blocks is consistently specified within the document:

```Python
a=b
```

```Python
b=c
```

Explanation: Both code blocks use backticks (```) as fence characters. This satisfies the rule because the fence style is consistent throughout the document.

Unlike the previous example, this case demonstrates consistent use of tildes (~) as fence characters.

~~~Python
a=b
~~~

~~~Python
b=c
~~~

Explanation: Both code blocks use tildes (~~~) as fence characters. This satisfies the rule because the fence style is consistent throughout the document, and tildes are also explicitly permitted under the tilde style.

Fix Description

Fenced code blocks will be fixed to use a single fence character style, as determined by the style configuration. If style is consistent, all fences will match the first fence encountered in the document. If style is backtick, all fences will be converted to backticks (```). If style is tilde, all fences will be converted to tildes (~~~).

Configuration

Prefixes
plugins.md048.
plugins.code-fence-style.

Value Name	Type	Default	Description
enabled	boolean	True	Whether the Rule Plugin is enabled.
style	string	consistent	Style of fenced code block fence characters expected in the document.

Valid Styles

Style Name	Description
consistent	The first Fenced Code Block specifies the style for the rest of the document.
backtick	Only backticks are to be used for Fenced Code Block elements.
tilde	Only tildes are to be used for Fenced Code Block elements.

Origination of Rule

This rule is largely inspired by the MarkdownLint rule MD048.