checker: ruby_divide_by_zero

[Thiru-moorthi]

Description

This PR introduces a Ruby checker that detects potential division by zero errors, which can cause runtime exceptions and application crashes.

Detection Logic

The checker flags the following patterns:

• Direct division by zero (e.g., 10 / 0).
• Variables assigned to zero and later used as divisors.
• Division by variables known to be zero through prior assignments.

Why is this a problem?

• Unhandled Exceptions: Raises a ZeroDivisionError, leading to crashes if not handled.
• Logic Flaws: May cause unpredictable behavior or incorrect results.
• Stability Risks: Lack of validation reflects poor error handling.

Recommended Remediation

Prevent division by zero with proper checks:

• Validate inputs before performing division.
• Use conditional checks or handle exceptions.

Example Fix

def safe_divide(a, b)
  return "Division by zero is not allowed" if b.zero?
  a / b
end

puts safe_divide(10, 2)  # => 5
puts safe_divide(10, 0)  # => "Division by zero is not allowed"

Exclusions

The checker excludes test files to minimize false positives:
test/**,*_test.rb,tests/**,__tests__/**

References

Ruby Zero Division Error

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1 Skipped Deployment

Name	Status	Preview	Comments	Updated (UTC)
globstar	⬜️ Ignored (Inspect)	Visit Preview		Feb 25, 2025 10:19am

[sourya-deepsource]

Removing line 21 (d = a/c) does not raise the issue in line 17, even though the issue still exists in line 19.