While programming in PHP often you will find that a simple echo or log statement is not sufficient. You have found out where a problem is happening but you have no clue why it is executing that code in the first place. This is where execution path comes in handy. With a simple call you can display the whole execution path of the code so far, every function that was executed, in which file and in which line number. Isn't that handy?

Use debug_print_backtrace() to print the full execution path of the code upto that point. You can also use debug_backtrace() which returns an associative array with the following data:
Possible returned elements from debug_backtrace()

Name Type Description
function string

The current function name. See also
__FUNCTION__.

line integer The current line number. See also
__LINE__.
file string The current file name. See also
__FILE__.
class string

The current class name. See also
__CLASS__

type string The current call type. If a method call, "->" is returned. If a static
method call, "::" is returned. If a function call, nothing is returned.
args array

If inside a function, this lists the functions arguments. If
inside an included file, this lists the included file name(s).