Numeric string handling

 Numeric string handling changed to be more intuitive and less error-prone. Trailing whitespace is now allowed in numeric strings for consistency with how leading whitespace is treated. This mostly affects:

• The is_numeric() function
• String-to-string comparisons
• Type declarations
• Increment and decrement operations

The concept of a “leading-numeric string” has been mostly dropped; the cases where this remains exist in order to ease migration. Strings which emitted an E_NOTICE “A non well-formed numeric value encountered” will now emit an E_WARNING “A non-numeric value encountered” and all strings which emitted an E_WARNING “A non-numeric value encountered” will now throw a TypeError. This mostly affects:

• Arithmetic operations
• Bitwise operations

This E_WARNING to TypeError change also affects the E_WARNING “Illegal string offset ‘string'” for illegal string offsets. There are no changes in the behavior of explicit casts to int/float from strings.

Named parameters

Support has also been added for named parameters. This has two major implications:

1. Renaming parameters becomes a breaking change. If a parameter is renamed then anywhere that function is called with named parameters will break.
2. The behaviour of call_user_func_array() changes. Previously call_user_func_array() could be called with an associative array. Now passing an associative array will be interpreted as using named parameters, which will cause an Exception to be thrown, if any of the named parameters do not exist.

API changes which could lead to type errors

Below we’ve compiled a list with some examples of API changes that will lead to type or argument errors where there were no indications as such in previous PHP versions.

• mktime() and gmmktime() now require at least one argument. time() can be used to get the current timestamp.
• spl_autoload_register() will now always throw a TypeError on invalid arguments, therefore the second argument $do_throw is ignored and a notice will be emitted if it is set to false.
• assert() will no longer evaluate string arguments, instead they will be treated like any other argument. assert($a == $b) should be used instead assert(‘$a == $b’). The assert.quiet_eval ini directive and the ASSERT_QUIET_EVAL constant have also been removed, as they will no longer have any effect.
• The $args argument of vsprintf(), vfprintf(), and vprintf() must now be an array. Previously any type was accepted.
• Arguments with a default value that resolves to null at runtime will no longer implicitly mark the argument type as nullable. Either use an explicit nullable type, or an explicit null default value instead.