This warning comes up if a model does not limit what attributes can be set through mass assignment.

In particular, this check looks for attr_accessible inside model definitions. If it is not found, this warning will be issued.

Brakeman also warns on use of attr_protected - especially since it was found to be vulnerable to bypass. Warnings for mass assignment on models using attr_protected will be reported, but at a lower confidence level.

Note that disabling mass assignment globally will suppress these warnings.

This cop checks that the ABC size of methods is not higher than the configured maximum. The ABC size is based on assignments, branches (method calls), and conditions. See http://c2.com/cgi/wiki?AbcMetric

This cop checks that the ABC size of methods is not higher than the configured maximum. The ABC size is based on assignments, branches (method calls), and conditions. See http://c2.com/cgi/wiki?AbcMetric

This cop checks that the ABC size of methods is not higher than the configured maximum. The ABC size is based on assignments, branches (method calls), and conditions. See http://c2.com/cgi/wiki?AbcMetric

Cognitive Complexity

Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.

A method's cognitive complexity is based on a few simple rules:

• Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
• Code is considered more complex for each "break in the linear flow of the code"
• Code is considered more complex when "flow breaking structures are nested"

Further reading

• Cognitive Complexity docs
• Cognitive Complexity: A new way of measuring understandability

This cop checks that the ABC size of methods is not higher than the configured maximum. The ABC size is based on assignments, branches (method calls), and conditions. See http://c2.com/cgi/wiki?AbcMetric

This cop tries to produce a complexity score that's a measure of the complexity the reader experiences when looking at a method. For that reason it considers when nodes as something that doesn't add as much complexity as an if or a &&. Except if it's one of those special case/when constructs where there's no expression after case. Then the cop treats it as an if/elsif/elsif... and lets all the when nodes count. In contrast to the CyclomaticComplexity cop, this cop considers else nodes as adding complexity.

Example:

def my_method                   # 1
  if cond                       # 1
    case var                    # 2 (0.8 + 4 * 0.2, rounded)
    when 1 then func_one
    when 2 then func_two
    when 3 then func_three
    when 4..10 then func_other
    end
  else                          # 1
    do_something until a && b   # 2
  end                           # ===
end                             # 7 complexity points

This cop checks that the cyclomatic complexity of methods is not higher than the configured maximum. The cyclomatic complexity is the number of linearly independent paths through a method. The algorithm counts decision points and adds one.

An if statement (or unless or ?:) increases the complexity by one. An else branch does not, since it doesn't add a decision point. The && operator (or keyword and) can be converted to a nested if statement, and ||/or is shorthand for a sequence of ifs, so they also add one. Loops can be said to have an exit condition, so they add one.

Cognitive Complexity

Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.

A method's cognitive complexity is based on a few simple rules:

• Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
• Code is considered more complex for each "break in the linear flow of the code"
• Code is considered more complex when "flow breaking structures are nested"

Further reading

• Cognitive Complexity docs
• Cognitive Complexity: A new way of measuring understandability

This cop tries to produce a complexity score that's a measure of the complexity the reader experiences when looking at a method. For that reason it considers when nodes as something that doesn't add as much complexity as an if or a &&. Except if it's one of those special case/when constructs where there's no expression after case. Then the cop treats it as an if/elsif/elsif... and lets all the when nodes count. In contrast to the CyclomaticComplexity cop, this cop considers else nodes as adding complexity.

Example:

def my_method                   # 1
  if cond                       # 1
    case var                    # 2 (0.8 + 4 * 0.2, rounded)
    when 1 then func_one
    when 2 then func_two
    when 3 then func_three
    when 4..10 then func_other
    end
  else                          # 1
    do_something until a && b   # 2
  end                           # ===
end                             # 7 complexity points

This cop checks that the cyclomatic complexity of methods is not higher than the configured maximum. The cyclomatic complexity is the number of linearly independent paths through a method. The algorithm counts decision points and adds one.

An if statement (or unless or ?:) increases the complexity by one. An else branch does not, since it doesn't add a decision point. The && operator (or keyword and) can be converted to a nested if statement, and ||/or is shorthand for a sequence of ifs, so they also add one. Loops can be said to have an exit condition, so they add one.

This cop checks if the length of a method exceeds some maximum value. Comment lines can optionally be ignored. The maximum allowed length is configurable.

This cop checks for excessive nesting of conditional and looping constructs.

You can configure if blocks are considered using the CountBlocks option. When set to false (the default) blocks are not counted towards the nesting level. Set to true to count blocks as well.

The maximum level of nesting allowed is configurable.

This cop checks for the use of output safety calls like htmlsafe, raw, and safeconcat. These methods do not escape content. They simply return a SafeBuffer containing the content as is. Instead, use safe_join to join content and escape it and concat to concatenate content and escape it, ensuring its safety.

Example:

user_content = "hi"

# bad
"
#{user_content}
".html_safe
# => ActiveSupport::SafeBuffer "
hi
"

# good
content_tag(:p, user_content)
# => ActiveSupport::SafeBuffer "
<b>hi</b>
"

# bad
out = ""
out << "
#{user_content}
"
out << "
#{user_content}
"
out.html_safe
# => ActiveSupport::SafeBuffer "
hi
hi
"

# good
out = []
out << content_tag(:li, user_content)
out << content_tag(:li, user_content)
safe_join(out)
# => ActiveSupport::SafeBuffer
#    "
<b>hi</b>
<b>hi</b>
"

# bad
out = "
trusted content
".html_safe
out.safe_concat(user_content)
# => ActiveSupport::SafeBuffer "
trusted_content
hi"

# good
out = "
trusted content
".html_safe
out.concat(user_content)
# => ActiveSupport::SafeBuffer
#    "
trusted_content
<b>hi</b>"

# safe, though maybe not good style
out = "trusted content"
result = out.concat(user_content)
# => String "trusted contenthi"
# because when rendered in ERB the String will be escaped:
# <%= result %>
# => trusted content<b>hi</b>

# bad
(user_content + " " + content_tag(:span, user_content)).html_safe
# => ActiveSupport::SafeBuffer "hi <span><b>hi</b></span>"

# good
safe_join([user_content, " ", content_tag(:span, user_content)])
# => ActiveSupport::SafeBuffer
#    "<b>hi</b> <span>&lt;b&gt;hi&lt;/b&gt;</span>"

This cop checks for the use of output safety calls like htmlsafe, raw, and safeconcat. These methods do not escape content. They simply return a SafeBuffer containing the content as is. Instead, use safe_join to join content and escape it and concat to concatenate content and escape it, ensuring its safety.

Example:

user_content = "hi"

# bad
"
#{user_content}
".html_safe
# => ActiveSupport::SafeBuffer "
hi
"

# good
content_tag(:p, user_content)
# => ActiveSupport::SafeBuffer "
<b>hi</b>
"

# bad
out = ""
out << "
#{user_content}
"
out << "
#{user_content}
"
out.html_safe
# => ActiveSupport::SafeBuffer "
hi
hi
"

# good
out = []
out << content_tag(:li, user_content)
out << content_tag(:li, user_content)
safe_join(out)
# => ActiveSupport::SafeBuffer
#    "
<b>hi</b>
<b>hi</b>
"

# bad
out = "
trusted content
".html_safe
out.safe_concat(user_content)
# => ActiveSupport::SafeBuffer "
trusted_content
hi"

# good
out = "
trusted content
".html_safe
out.concat(user_content)
# => ActiveSupport::SafeBuffer
#    "
trusted_content
<b>hi</b>"

# safe, though maybe not good style
out = "trusted content"
result = out.concat(user_content)
# => String "trusted contenthi"
# because when rendered in ERB the String will be escaped:
# <%= result %>
# => trusted content<b>hi</b>

# bad
(user_content + " " + content_tag(:span, user_content)).html_safe
# => ActiveSupport::SafeBuffer "hi <span><b>hi</b></span>"

# good
safe_join([user_content, " ", content_tag(:span, user_content)])
# => ActiveSupport::SafeBuffer
#    "<b>hi</b> <span>&lt;b&gt;hi&lt;/b&gt;</span>"

This cop checks for the use of output safety calls like htmlsafe, raw, and safeconcat. These methods do not escape content. They simply return a SafeBuffer containing the content as is. Instead, use safe_join to join content and escape it and concat to concatenate content and escape it, ensuring its safety.

Example:

user_content = "hi"

# bad
"
#{user_content}
".html_safe
# => ActiveSupport::SafeBuffer "
hi
"

# good
content_tag(:p, user_content)
# => ActiveSupport::SafeBuffer "
<b>hi</b>
"

# bad
out = ""
out << "
#{user_content}
"
out << "
#{user_content}
"
out.html_safe
# => ActiveSupport::SafeBuffer "
hi
hi
"

# good
out = []
out << content_tag(:li, user_content)
out << content_tag(:li, user_content)
safe_join(out)
# => ActiveSupport::SafeBuffer
#    "
<b>hi</b>
<b>hi</b>
"

# bad
out = "
trusted content
".html_safe
out.safe_concat(user_content)
# => ActiveSupport::SafeBuffer "
trusted_content
hi"

# good
out = "
trusted content
".html_safe
out.concat(user_content)
# => ActiveSupport::SafeBuffer
#    "
trusted_content
<b>hi</b>"

# safe, though maybe not good style
out = "trusted content"
result = out.concat(user_content)
# => String "trusted contenthi"
# because when rendered in ERB the String will be escaped:
# <%= result %>
# => trusted content<b>hi</b>

# bad
(user_content + " " + content_tag(:span, user_content)).html_safe
# => ActiveSupport::SafeBuffer "hi <span><b>hi</b></span>"

# good
safe_join([user_content, " ", content_tag(:span, user_content)])
# => ActiveSupport::SafeBuffer
#    "<b>hi</b> <span>&lt;b&gt;hi&lt;/b&gt;</span>"

This cop checks for the use of output safety calls like htmlsafe, raw, and safeconcat. These methods do not escape content. They simply return a SafeBuffer containing the content as is. Instead, use safe_join to join content and escape it and concat to concatenate content and escape it, ensuring its safety.

Example:

user_content = "hi"

# bad
"
#{user_content}
".html_safe
# => ActiveSupport::SafeBuffer "
hi
"

# good
content_tag(:p, user_content)
# => ActiveSupport::SafeBuffer "
<b>hi</b>
"

# bad
out = ""
out << "
#{user_content}
"
out << "
#{user_content}
"
out.html_safe
# => ActiveSupport::SafeBuffer "
hi
hi
"

# good
out = []
out << content_tag(:li, user_content)
out << content_tag(:li, user_content)
safe_join(out)
# => ActiveSupport::SafeBuffer
#    "
<b>hi</b>
<b>hi</b>
"

# bad
out = "
trusted content
".html_safe
out.safe_concat(user_content)
# => ActiveSupport::SafeBuffer "
trusted_content
hi"

# good
out = "
trusted content
".html_safe
out.concat(user_content)
# => ActiveSupport::SafeBuffer
#    "
trusted_content
<b>hi</b>"

# safe, though maybe not good style
out = "trusted content"
result = out.concat(user_content)
# => String "trusted contenthi"
# because when rendered in ERB the String will be escaped:
# <%= result %>
# => trusted content<b>hi</b>

# bad
(user_content + " " + content_tag(:span, user_content)).html_safe
# => ActiveSupport::SafeBuffer "hi <span><b>hi</b></span>"

# good
safe_join([user_content, " ", content_tag(:span, user_content)])
# => ActiveSupport::SafeBuffer
#    "<b>hi</b> <span>&lt;b&gt;hi&lt;/b&gt;</span>"

This cop checks for the use of output safety calls like htmlsafe, raw, and safeconcat. These methods do not escape content. They simply return a SafeBuffer containing the content as is. Instead, use safe_join to join content and escape it and concat to concatenate content and escape it, ensuring its safety.

Example:

user_content = "hi"

# bad
"
#{user_content}
".html_safe
# => ActiveSupport::SafeBuffer "
hi
"

# good
content_tag(:p, user_content)
# => ActiveSupport::SafeBuffer "
<b>hi</b>
"

# bad
out = ""
out << "
#{user_content}
"
out << "
#{user_content}
"
out.html_safe
# => ActiveSupport::SafeBuffer "
hi
hi
"

# good
out = []
out << content_tag(:li, user_content)
out << content_tag(:li, user_content)
safe_join(out)
# => ActiveSupport::SafeBuffer
#    "
<b>hi</b>
<b>hi</b>
"

# bad
out = "
trusted content
".html_safe
out.safe_concat(user_content)
# => ActiveSupport::SafeBuffer "
trusted_content
hi"

# good
out = "
trusted content
".html_safe
out.concat(user_content)
# => ActiveSupport::SafeBuffer
#    "
trusted_content
<b>hi</b>"

# safe, though maybe not good style
out = "trusted content"
result = out.concat(user_content)
# => String "trusted contenthi"
# because when rendered in ERB the String will be escaped:
# <%= result %>
# => trusted content<b>hi</b>

# bad
(user_content + " " + content_tag(:span, user_content)).html_safe
# => ActiveSupport::SafeBuffer "hi <span><b>hi</b></span>"

# good
safe_join([user_content, " ", content_tag(:span, user_content)])
# => ActiveSupport::SafeBuffer
#    "<b>hi</b> <span>&lt;b&gt;hi&lt;/b&gt;</span>"

This cop checks for the use of output safety calls like htmlsafe, raw, and safeconcat. These methods do not escape content. They simply return a SafeBuffer containing the content as is. Instead, use safe_join to join content and escape it and concat to concatenate content and escape it, ensuring its safety.

Example:

user_content = "hi"

# bad
"
#{user_content}
".html_safe
# => ActiveSupport::SafeBuffer "
hi
"

# good
content_tag(:p, user_content)
# => ActiveSupport::SafeBuffer "
<b>hi</b>
"

# bad
out = ""
out << "
#{user_content}
"
out << "
#{user_content}
"
out.html_safe
# => ActiveSupport::SafeBuffer "
hi
hi
"

# good
out = []
out << content_tag(:li, user_content)
out << content_tag(:li, user_content)
safe_join(out)
# => ActiveSupport::SafeBuffer
#    "
<b>hi</b>
<b>hi</b>
"

# bad
out = "
trusted content
".html_safe
out.safe_concat(user_content)
# => ActiveSupport::SafeBuffer "
trusted_content
hi"

# good
out = "
trusted content
".html_safe
out.concat(user_content)
# => ActiveSupport::SafeBuffer
#    "
trusted_content
<b>hi</b>"

# safe, though maybe not good style
out = "trusted content"
result = out.concat(user_content)
# => String "trusted contenthi"
# because when rendered in ERB the String will be escaped:
# <%= result %>
# => trusted content<b>hi</b>

# bad
(user_content + " " + content_tag(:span, user_content)).html_safe
# => ActiveSupport::SafeBuffer "hi <span><b>hi</b></span>"

# good
safe_join([user_content, " ", content_tag(:span, user_content)])
# => ActiveSupport::SafeBuffer
#    "<b>hi</b> <span>&lt;b&gt;hi&lt;/b&gt;</span>"

This cop checks for the use of output safety calls like htmlsafe, raw, and safeconcat. These methods do not escape content. They simply return a SafeBuffer containing the content as is. Instead, use safe_join to join content and escape it and concat to concatenate content and escape it, ensuring its safety.

Example:

user_content = "hi"

# bad
"
#{user_content}
".html_safe
# => ActiveSupport::SafeBuffer "
hi
"

# good
content_tag(:p, user_content)
# => ActiveSupport::SafeBuffer "
<b>hi</b>
"

# bad
out = ""
out << "
#{user_content}
"
out << "
#{user_content}
"
out.html_safe
# => ActiveSupport::SafeBuffer "
hi
hi
"

# good
out = []
out << content_tag(:li, user_content)
out << content_tag(:li, user_content)
safe_join(out)
# => ActiveSupport::SafeBuffer
#    "
<b>hi</b>
<b>hi</b>
"

# bad
out = "
trusted content
".html_safe
out.safe_concat(user_content)
# => ActiveSupport::SafeBuffer "
trusted_content
hi"

# good
out = "
trusted content
".html_safe
out.concat(user_content)
# => ActiveSupport::SafeBuffer
#    "
trusted_content
<b>hi</b>"

# safe, though maybe not good style
out = "trusted content"
result = out.concat(user_content)
# => String "trusted contenthi"
# because when rendered in ERB the String will be escaped:
# <%= result %>
# => trusted content<b>hi</b>

# bad
(user_content + " " + content_tag(:span, user_content)).html_safe
# => ActiveSupport::SafeBuffer "hi <span><b>hi</b></span>"

# good
safe_join([user_content, " ", content_tag(:span, user_content)])
# => ActiveSupport::SafeBuffer
#    "<b>hi</b> <span>&lt;b&gt;hi&lt;/b&gt;</span>"

This cop checks for the use of output safety calls like htmlsafe, raw, and safeconcat. These methods do not escape content. They simply return a SafeBuffer containing the content as is. Instead, use safe_join to join content and escape it and concat to concatenate content and escape it, ensuring its safety.

Example:

user_content = "hi"

# bad
"
#{user_content}
".html_safe
# => ActiveSupport::SafeBuffer "
hi
"

# good
content_tag(:p, user_content)
# => ActiveSupport::SafeBuffer "
<b>hi</b>
"

# bad
out = ""
out << "
#{user_content}
"
out << "
#{user_content}
"
out.html_safe
# => ActiveSupport::SafeBuffer "
hi
hi
"

# good
out = []
out << content_tag(:li, user_content)
out << content_tag(:li, user_content)
safe_join(out)
# => ActiveSupport::SafeBuffer
#    "
<b>hi</b>
<b>hi</b>
"

# bad
out = "
trusted content
".html_safe
out.safe_concat(user_content)
# => ActiveSupport::SafeBuffer "
trusted_content
hi"

# good
out = "
trusted content
".html_safe
out.concat(user_content)
# => ActiveSupport::SafeBuffer
#    "
trusted_content
<b>hi</b>"

# safe, though maybe not good style
out = "trusted content"
result = out.concat(user_content)
# => String "trusted contenthi"
# because when rendered in ERB the String will be escaped:
# <%= result %>
# => trusted content<b>hi</b>

# bad
(user_content + " " + content_tag(:span, user_content)).html_safe
# => ActiveSupport::SafeBuffer "hi <span><b>hi</b></span>"

# good
safe_join([user_content, " ", content_tag(:span, user_content)])
# => ActiveSupport::SafeBuffer
#    "<b>hi</b> <span>&lt;b&gt;hi&lt;/b&gt;</span>"

This cop checks for the use of output safety calls like htmlsafe, raw, and safeconcat. These methods do not escape content. They simply return a SafeBuffer containing the content as is. Instead, use safe_join to join content and escape it and concat to concatenate content and escape it, ensuring its safety.

Example:

user_content = "hi"

# bad
"
#{user_content}
".html_safe
# => ActiveSupport::SafeBuffer "
hi
"

# good
content_tag(:p, user_content)
# => ActiveSupport::SafeBuffer "
<b>hi</b>
"

# bad
out = ""
out << "
#{user_content}
"
out << "
#{user_content}
"
out.html_safe
# => ActiveSupport::SafeBuffer "
hi
hi
"

# good
out = []
out << content_tag(:li, user_content)
out << content_tag(:li, user_content)
safe_join(out)
# => ActiveSupport::SafeBuffer
#    "
<b>hi</b>
<b>hi</b>
"

# bad
out = "
trusted content
".html_safe
out.safe_concat(user_content)
# => ActiveSupport::SafeBuffer "
trusted_content
hi"

# good
out = "
trusted content
".html_safe
out.concat(user_content)
# => ActiveSupport::SafeBuffer
#    "
trusted_content
<b>hi</b>"

# safe, though maybe not good style
out = "trusted content"
result = out.concat(user_content)
# => String "trusted contenthi"
# because when rendered in ERB the String will be escaped:
# <%= result %>
# => trusted content<b>hi</b>

# bad
(user_content + " " + content_tag(:span, user_content)).html_safe
# => ActiveSupport::SafeBuffer "hi <span><b>hi</b></span>"

# good
safe_join([user_content, " ", content_tag(:span, user_content)])
# => ActiveSupport::SafeBuffer
#    "<b>hi</b> <span>&lt;b&gt;hi&lt;/b&gt;</span>"

This cop checks for the use of output safety calls like htmlsafe, raw, and safeconcat. These methods do not escape content. They simply return a SafeBuffer containing the content as is. Instead, use safe_join to join content and escape it and concat to concatenate content and escape it, ensuring its safety.

Example:

user_content = "hi"

# bad
"
#{user_content}
".html_safe
# => ActiveSupport::SafeBuffer "
hi
"

# good
content_tag(:p, user_content)
# => ActiveSupport::SafeBuffer "
<b>hi</b>
"

# bad
out = ""
out << "
#{user_content}
"
out << "
#{user_content}
"
out.html_safe
# => ActiveSupport::SafeBuffer "
hi
hi
"

# good
out = []
out << content_tag(:li, user_content)
out << content_tag(:li, user_content)
safe_join(out)
# => ActiveSupport::SafeBuffer
#    "
<b>hi</b>
<b>hi</b>
"

# bad
out = "
trusted content
".html_safe
out.safe_concat(user_content)
# => ActiveSupport::SafeBuffer "
trusted_content
hi"

# good
out = "
trusted content
".html_safe
out.concat(user_content)
# => ActiveSupport::SafeBuffer
#    "
trusted_content
<b>hi</b>"

# safe, though maybe not good style
out = "trusted content"
result = out.concat(user_content)
# => String "trusted contenthi"
# because when rendered in ERB the String will be escaped:
# <%= result %>
# => trusted content<b>hi</b>

# bad
(user_content + " " + content_tag(:span, user_content)).html_safe
# => ActiveSupport::SafeBuffer "hi <span><b>hi</b></span>"

# good
safe_join([user_content, " ", content_tag(:span, user_content)])
# => ActiveSupport::SafeBuffer
#    "<b>hi</b> <span>&lt;b&gt;hi&lt;/b&gt;</span>"

This cop checks for the use of output safety calls like htmlsafe, raw, and safeconcat. These methods do not escape content. They simply return a SafeBuffer containing the content as is. Instead, use safe_join to join content and escape it and concat to concatenate content and escape it, ensuring its safety.

Example:

user_content = "hi"

# bad
"
#{user_content}
".html_safe
# => ActiveSupport::SafeBuffer "
hi
"

# good
content_tag(:p, user_content)
# => ActiveSupport::SafeBuffer "
<b>hi</b>
"

# bad
out = ""
out << "
#{user_content}
"
out << "
#{user_content}
"
out.html_safe
# => ActiveSupport::SafeBuffer "
hi
hi
"

# good
out = []
out << content_tag(:li, user_content)
out << content_tag(:li, user_content)
safe_join(out)
# => ActiveSupport::SafeBuffer
#    "
<b>hi</b>
<b>hi</b>
"

# bad
out = "
trusted content
".html_safe
out.safe_concat(user_content)
# => ActiveSupport::SafeBuffer "
trusted_content
hi"

# good
out = "
trusted content
".html_safe
out.concat(user_content)
# => ActiveSupport::SafeBuffer
#    "
trusted_content
<b>hi</b>"

# safe, though maybe not good style
out = "trusted content"
result = out.concat(user_content)
# => String "trusted contenthi"
# because when rendered in ERB the String will be escaped:
# <%= result %>
# => trusted content<b>hi</b>

# bad
(user_content + " " + content_tag(:span, user_content)).html_safe
# => ActiveSupport::SafeBuffer "hi <span><b>hi</b></span>"

# good
safe_join([user_content, " ", content_tag(:span, user_content)])
# => ActiveSupport::SafeBuffer
#    "<b>hi</b> <span>&lt;b&gt;hi&lt;/b&gt;</span>"

This cop checks for the use of output safety calls like htmlsafe, raw, and safeconcat. These methods do not escape content. They simply return a SafeBuffer containing the content as is. Instead, use safe_join to join content and escape it and concat to concatenate content and escape it, ensuring its safety.

Example:

user_content = "hi"

# bad
"
#{user_content}
".html_safe
# => ActiveSupport::SafeBuffer "
hi
"

# good
content_tag(:p, user_content)
# => ActiveSupport::SafeBuffer "
<b>hi</b>
"

# bad
out = ""
out << "
#{user_content}
"
out << "
#{user_content}
"
out.html_safe
# => ActiveSupport::SafeBuffer "
hi
hi
"

# good
out = []
out << content_tag(:li, user_content)
out << content_tag(:li, user_content)
safe_join(out)
# => ActiveSupport::SafeBuffer
#    "
<b>hi</b>
<b>hi</b>
"

# bad
out = "
trusted content
".html_safe
out.safe_concat(user_content)
# => ActiveSupport::SafeBuffer "
trusted_content
hi"

# good
out = "
trusted content
".html_safe
out.concat(user_content)
# => ActiveSupport::SafeBuffer
#    "
trusted_content
<b>hi</b>"

# safe, though maybe not good style
out = "trusted content"
result = out.concat(user_content)
# => String "trusted contenthi"
# because when rendered in ERB the String will be escaped:
# <%= result %>
# => trusted content<b>hi</b>

# bad
(user_content + " " + content_tag(:span, user_content)).html_safe
# => ActiveSupport::SafeBuffer "hi <span><b>hi</b></span>"

# good
safe_join([user_content, " ", content_tag(:span, user_content)])
# => ActiveSupport::SafeBuffer
#    "<b>hi</b> <span>&lt;b&gt;hi&lt;/b&gt;</span>"

This cop checks for the use of output safety calls like htmlsafe, raw, and safeconcat. These methods do not escape content. They simply return a SafeBuffer containing the content as is. Instead, use safe_join to join content and escape it and concat to concatenate content and escape it, ensuring its safety.

Example:

user_content = "hi"

# bad
"
#{user_content}
".html_safe
# => ActiveSupport::SafeBuffer "
hi
"

# good
content_tag(:p, user_content)
# => ActiveSupport::SafeBuffer "
<b>hi</b>
"

# bad
out = ""
out << "
#{user_content}
"
out << "
#{user_content}
"
out.html_safe
# => ActiveSupport::SafeBuffer "
hi
hi
"

# good
out = []
out << content_tag(:li, user_content)
out << content_tag(:li, user_content)
safe_join(out)
# => ActiveSupport::SafeBuffer
#    "
<b>hi</b>
<b>hi</b>
"

# bad
out = "
trusted content
".html_safe
out.safe_concat(user_content)
# => ActiveSupport::SafeBuffer "
trusted_content
hi"

# good
out = "
trusted content
".html_safe
out.concat(user_content)
# => ActiveSupport::SafeBuffer
#    "
trusted_content
<b>hi</b>"

# safe, though maybe not good style
out = "trusted content"
result = out.concat(user_content)
# => String "trusted contenthi"
# because when rendered in ERB the String will be escaped:
# <%= result %>
# => trusted content<b>hi</b>

# bad
(user_content + " " + content_tag(:span, user_content)).html_safe
# => ActiveSupport::SafeBuffer "hi <span><b>hi</b></span>"

# good
safe_join([user_content, " ", content_tag(:span, user_content)])
# => ActiveSupport::SafeBuffer
#    "<b>hi</b> <span>&lt;b&gt;hi&lt;/b&gt;</span>"

Duplicated Code

Duplicated code can lead to software that is hard to understand and difficult to change. The Don't Repeat Yourself (DRY) principle states:

Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.

When you violate DRY, bugs and maintenance problems are sure to follow. Duplicated code has a tendency to both continue to replicate and also to diverge (leaving bugs as two similar implementations differ in subtle ways).

Tuning

This issue has a mass of 45.

We set useful threshold defaults for the languages we support but you may want to adjust these settings based on your project guidelines.

The threshold configuration represents the minimum mass a code block must have to be analyzed for duplication. The lower the threshold, the more fine-grained the comparison.

If the engine is too easily reporting duplication, try raising the threshold. If you suspect that the engine isn't catching enough duplication, try lowering the threshold. The best setting tends to differ from language to language.

See codeclimate-duplication's documentation for more information about tuning the mass threshold in your .codeclimate.yml.

Refactorings

• Extract Method
• Extract Class
• Form Template Method
• Introduce Null Object
• Pull Up Method
• Pull Up Field
• Substitute Algorithm

Further Reading

• Don't Repeat Yourself on the C2 Wiki
• Duplicated Code on SourceMaking
• Refactoring: Improving the Design of Existing Code by Martin Fowler. Duplicated Code, p76

This cop checks for every useless assignment to local variable in every scope. The basic idea for this cop was from the warning of ruby -cw:

assigned but unused variable - foo

Currently this cop has advanced logic that detects unreferenced reassignments and properly handles varied cases such as branch, loop, rescue, ensure, etc.

Example:

# bad

def some_method
  some_var = 1
  do_something
end

Example:

# good

def some_method
  some_var = 1
  do_something(some_var)
end

Checks for uses of if with a negated condition. Only ifs without else are considered. There are three different styles:

- both
- prefix
- postfix

Example: EnforcedStyle: both (default)

# enforces `unless` for `prefix` and `postfix` conditionals

# bad

if !foo
  bar
end

# good

unless foo
  bar
end

# bad

bar if !foo

# good

bar unless foo

Example: EnforcedStyle: prefix

# enforces `unless` for just `prefix` conditionals

# bad

if !foo
  bar
end

# good

unless foo
  bar
end

# good

bar if !foo

Example: EnforcedStyle: postfix

# enforces `unless` for just `postfix` conditionals

# bad

bar if !foo

# good

bar unless foo

# good

if !foo
  bar
end

This cop checks for optional arguments to methods that do not come at the end of the argument list

Example:

# bad
def foo(a = 1, b, c)
end

# good
def baz(a, b, c = 1)
end

def foobar(a = 1, b = 2, c = 3)
end