What mechanisms exist for disrupting the operation of a specific part of a project?

Exceptions: Allow stopping code execution when an error occurs and transferring control to begin/rescue/ensure blocks.

begin
  # Code that may cause an error
  result = 1 / 0
rescue ZeroDivisionError => e
  # Handling specific error
  puts "Division by zero error: #{e.message}"
  # Possibly logging or alternative execution
rescue StandardError => e
  # Handling other standard errors
  puts "Another error occurred: #{e.message}"
ensure
  # Code that always executes, regardless of error presence
  puts "End of block"
end

Raise: Explicitly raising an exception, for both standard and custom error classes.

# Raising a standard exception
raise "Something went wrong"

# Raising with a specific error class
raise MyCustomError, "Invalid value"

exit, abort, Kernel#exit!: Methods to terminate program execution. exit! terminates immediately without calling at_exit handlers.

# Normal program termination
exit(0) # 0 indicates successful termination

# Termination with an error
abort("Terminating due to a critical error")

# Forced termination
Kernel.exit!(1)

Thread#raise: Allows raising an exception in another thread.

thread = Thread.new do
  begin
    loop { sleep 1 }
  rescue => e
    puts "Thread caught: #{e.class}"
  end
end

sleep 2
thread.raise StandardError, "Stop the thread"
thread.join

Programming errors (logical, syntactic): Incorrectly written code can lead to runtime failures.

# Syntactic error (missing end)
def my_method
  puts "Hello"

# Logical error (infinite loop)
while true
  puts "Loop"
end

Operating system signals (SIGTERM, SIGINT, etc.): Can interrupt program execution from outside.

# Simple example handling SIGINT (Ctrl+C)
Signal.trap("INT") { puts "\nSIGINT caught. Exiting..."; exit }

loop { sleep 1 }

Assertions (especially during development and testing): Mechanisms to verify conditions, throwing exceptions or performing other actions when violated. In Ruby, often implemented with testing libraries.

# Example using MiniTest library
require 'minitest/autorun'

class MyTest < Minitest::Test
  def test_division
    # Assertion: division of 4 by 2 equals 2
    assert_equal 2, 4 / 2
    # Assertion: division by zero should raise ZeroDivisionError
    assert_raises(ZeroDivisionError) { 1 / 0 }
  end
end