MSC00-PL. Detect and remove dead code

Code that is never executed is known as dead code . Typically, the presence of dead code indicates that a logic error has occurred as a result of changes to a program or the program's environment. To improve readability and ensure that logic errors are resolved, dead code should be identified, understood, and eliminated.

Noncompliant Code Example

This noncompliant code example contains code that cannot possibly execute.

sub fix_name {
  my $name = shift;

  if ($name eq "") {
    return $name;
  }
  $name =~ s/^([a-z])/\U$1\E/g;
  $name =~ s/ ([a-z])/ \U$1\E/g;
  if (length( $name) == 0) {
    die "Invalid name";  # cannot happen
  }
  return $name;
}

Compliant Solution

This compliant solution makes the dead code reachable.

sub fix_name {
  my $name = shift;

  $name =~ s/^([a-z])/\U$1\E/g;
  $name =~ s/ ([a-z])/ \U$1\E/g;
  if (length( $name) == 0) {
    die "Invalid name";  # cannot happen
  }
  return $name;
}

Risk Assessment

The presence dead code may indicate logic errors that can lead to unintended program behavior. As a result, resolving dead code can be an in-depth process requiring significant analysis.


Recommendation	Severity	Likelihood	Detectable	Repairable	Priority	Level
MSC00-PL	Low	Unlikely	No	Yes	P2	L3

Automated Detection

Tool	Diagnostic
Perl::Critic	Subroutines::ProhibitUnusedPrivateSubroutines
Perl::Critic	ControlStructures::ProhibitUnreachableCode
Security Reviewer - Static Reviewer	CWE561P1 PERL_D81 CWE561P15 CWE561P19 CWE561P2 CWE570P1


SEI CERT C Coding Standard	MSC07-C. Detect and remove dead code

Bibliography

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