Note that using Incrementing/Decrementing operators on string is legal
<?php
$str = "";
echo ++$str; // output: 1
?>
New E_WARNING and E_NOTICE errors
have been introduced when invalid strings are coerced using operators
expecting numbers (+ -
* / **
% << >>
| & ^) or their
assignment equivalents. An E_NOTICE is emitted when the
string begins with a numeric value but contains trailing non-numeric
characters, and an E_WARNING is emitted when the string
does not contain a numeric value.
<?php
'1b' + 'something';
以上例程会输出：
Notice: A non well formed numeric value encountered in %s on line %d Warning: A non-numeric value encountered in %s on line %d
Previously, 3-octet octal string escape sequences would overflow silently.
Now, they will still overflow, but E_WARNING will be
emitted.
<?php
var_dump("\500");
以上例程会输出：
Warning: Octal escape sequence overflow \500 is greater than \377 in %s on line %d string(1) "@"
Whilst $this is considered a special variable in PHP, it lacked proper checks to ensure it wasn't used as a variable name or reassigned. This has now been rectified to ensure that $this cannot be a user-defined variable, reassigned to a different value, or be globalised.
Session IDs will no longer be hashed upon generation. With this change brings about the removal of the following four ini settings:
session.entropy_file
session.entropy_length
session.hash_function
session.hash_bits_per_character
And the addition of the following two ini settings:
session.sid_length - defines the length of the
session ID, defaulting to 32 characters for backwards compatibility)
session.sid_bits_per_character - defines the number
of bits to be stored per character (i.e. increases the range of characters
that can be used in the session ID), defaulting to 4 for backwards
compatibility
precisionIf the value is set to -1, then the dtoa mode 0 is used. The default value is still 14.
serialize_precisionIf the value is set to -1, then the dtoa mode 0 is used. The value -1 is now used by default.
gd.jpeg_ignore_warningThe default of this php.ini setting has been changed to 1, so by default libjpeg warnings are ignored.
opcache.enable_cliThe default of this php.ini setting has been changed to 1 (enabled) in PHP 7.1.2.
Session IDs will now only be generated with a CSPRNG.
NULL is allowed
TypeError exceptions for arg_info type checks will
now provide more informative error messages. If the parameter type or return
type accepts NULL (by either having a default value of NULL or being a
nullable type), then the error message will now mention this with a message
of "must be ... or null" or "must ... or be null."
Note that using Incrementing/Decrementing operators on string is legal
<?php
$str = "";
echo ++$str; // output: 1
?>