MD024 - Multiple headers with the same content

Tags: headers

Aliases: no-duplicate-header

Parameters: allowdifferentnesting (boolean; default false)

This rule is triggered if there are multiple headers in the document that have the same text:

# Some text

## Some text

To fix this, ensure that the content of each header is different:

# Some text

## Some more text

Rationale: Some markdown parses generate anchors for headers based on the header name, and having headers with the same content can cause problems with this.

If the parameter allow_different_nesting is set to true, header duplication under different nesting is allowed, like it usually happens in change logs:

# Change log

## 2.0.0

### Bug fixes

### Features

## 1.0.0

### Bug fixes

MD009 - Trailing spaces

Tags: whitespace

Aliases: no-trailing-spaces

Parameters: br_spaces (number; default: 0)

This rule is triggered on any lines that end with whitespace. To fix this, find the line that is triggered and remove any trailing spaces from the end.

The brspaces parameter allows an exception to this rule for a specific amount of trailing spaces used to insert an explicit line break/br element. For example, set brspaces to 2 to allow exactly 2 spaces at the end of a line.

Note: you have to set brspaces to 2 or higher for this exception to take effect - you can't insert a br element with just a single trailing space, so if you set brspaces to 1, the exception will be disabled, just as if it was set to the default of 0.

MD033 - Inline HTML

Tags: html

Aliases: no-inline-html

This rule is triggered whenever raw HTML is used in a markdown document:

Inline HTML header

To fix this, use 'pure' markdown instead of including raw HTML:

# Markdown header

Rationale: Raw HTML is allowed in markdown, but this rule is included for those who want their documents to only include "pure" markdown, or for those who are rendering markdown documents in something other than HTML.

Jump statements (return, break, continue, and goto) and throw expressions move control flow out of the current code block. Typically, any statements in a block that come after a jump or throw are simply wasted keystrokes lying in wait to confuse the unwary.

Rarely, as illustrated below, code after a jump or throw is reachable. However, such code is difficult to understand, and should be refactored.

Noncompliant Code Example

function fun($a) {
  $i = 10;
  return $i + $a;
  $i++;             // this is never executed
}

function foo($a) {
  if ($a == 5) {
    goto error;
  } else {
    // do the job
  }
  return;

  error:
    printf("don't use 5"); // this is reachable but unreadable

}

Compliant Solution

function fun($a) {
  $i = 10;
  return $i + $a;
}

function foo($a) {
  if ($a == 5) {
    handleError();
  } else {
    // do the job
  }
  return;
}

See

• MISRA C:2004, 14.1 - There shall be no unreachable code
• MISRA C++:2008, 0-1-1 - A project shall not contain unreachable code
• MISRA C++:2008, 0-1-9 - There shall be no dead code
• MISRA C:2012, 2.1 - A project shall not contain unreachable code
• MISRA C:2012, 2.2 - There shall be no dead code
• MITRE, CWE-561 - Dead Code
• CERT, MSC56-J. - Detect and remove superfluous code and values
• CERT, MSC12-C. - Detect and remove code that has no effect or is never executed
• CERT, MSC07-CPP. - Detect and remove dead code

Jump statements (return, break, continue, and goto) and throw expressions move control flow out of the current code block. Typically, any statements in a block that come after a jump or throw are simply wasted keystrokes lying in wait to confuse the unwary.

Rarely, as illustrated below, code after a jump or throw is reachable. However, such code is difficult to understand, and should be refactored.

Noncompliant Code Example

function fun($a) {
  $i = 10;
  return $i + $a;
  $i++;             // this is never executed
}

function foo($a) {
  if ($a == 5) {
    goto error;
  } else {
    // do the job
  }
  return;

  error:
    printf("don't use 5"); // this is reachable but unreadable

}

Compliant Solution

function fun($a) {
  $i = 10;
  return $i + $a;
}

function foo($a) {
  if ($a == 5) {
    handleError();
  } else {
    // do the job
  }
  return;
}

See

• MISRA C:2004, 14.1 - There shall be no unreachable code
• MISRA C++:2008, 0-1-1 - A project shall not contain unreachable code
• MISRA C++:2008, 0-1-9 - There shall be no dead code
• MISRA C:2012, 2.1 - A project shall not contain unreachable code
• MISRA C:2012, 2.2 - There shall be no dead code
• MITRE, CWE-561 - Dead Code
• CERT, MSC56-J. - Detect and remove superfluous code and values
• CERT, MSC12-C. - Detect and remove code that has no effect or is never executed
• CERT, MSC07-CPP. - Detect and remove dead code