E_STRICT 有什么作用?

正在检查 5.6.0 版:

Checking out version 5.6.0:

cd php-src
git checkout PHP-5.6.0

搜索包含 E_STRICT 的所有 C 文件(带有 .h 和 .c 扩展名的文件):

Searching for all C files (ones with .h and .c extensions) containing E_STRICT:

grep --include=*.[ch] -rl . -e E_STRICT

手动查看 (21) 个匹配文件中的每一个以查找发出 E_STRICT 警告的代码，尝试推断发出警告的情况(我不是 C程序员，但对这些东西做出很好的猜测并不太难，尤其是代码中的人类可读错误消息可以指导您)然后在交互式 PHP shell 中测试它们以确保我是对的.

Manually looking through each of the (21) matched files to find code emitting E_STRICT warnings, attempting to deduce the circumstances in which the warning would be emitted (I'm not a C programmer, but it's not too hard to take a good guess at this stuff, especially with the human-readable error messages right there in the code to guide you) then testing them at the interactive PHP shell to make sure I was right.

鉴于上述方法略显粗糙，并且依赖于以下假设:E_STRICT 可以在源代码中所有发出 E_STRICT 警告的地方旁边找到，我可能遗漏了一些东西 - 但希望这至少接近成为一个全面的列表.

Given that the methodology described above is slightly crude and depends upon the assumption that E_STRICT can be found in the source code next to all places where E_STRICT warnings are emitted, it's possible I've missed some stuff - but this is hopefully at least close to being a comprehensive list.

1. 调用mktime()没有参数

php > mktime();
PHP Strict Standards:  mktime(): You should be using the time() function
instead in php shell code on line 1

使用资源作为数组索引>

Using a resource as an array index

php > $file_pointer = fopen('/dev/null', 'r');
php > $array = [3,4,5,6];
php > $array[$file_pointer];
PHP Strict Standards:  Resource ID#2 used as offset, casting to integer (2)
in php shell code on line 1

将 UTF-8 以外的多字节编码传递给 htmlentities

php > htmlentities('qwertyuiop', 0, 'BIG5');
PHP Strict Standards:  htmlentities(): Only basic entities substitution is
supported for multi-byte encodings other than UTF-8; functionality is
equivalent to htmlspecialchars in php shell code on line 1

声明一个抽象 静态方法

php > abstract class Foo { static abstract function bar(); }
PHP Strict Standards:  Static function Foo::bar() should not be abstract in
php shell code on line 1

使用 声明一个类__construct 方法和 旧式构造函数以类命名的函数

php > class MyClass {
php {     function MyClass () {}
php {     function __construct () {}
php { }
PHP Strict Standards:  Redefining already defined constructor for class
MyClass in php shell code on line 3

调用mysqli_next_result或 mysqli::next_result 在没有准备下一个结果的 Mysqli 连接对象上

Calling mysqli_next_result or mysqli::next_result on a Mysqli connection object that does not have a next result to prepare

php > $conn = mysqli_connect('127.0.0.1', 'root');
php > mysqli_multi_query($conn, "SELECT 'first'; SELECT 'second';");
php > echo mysqli_use_result($conn)->fetch_row()[0];
first
php > mysqli_next_result($conn);
php > echo mysqli_use_result($conn)->fetch_row()[0];
second
php > mysqli_next_result($conn);
PHP Strict Standards:  mysqli_next_result(): There is no next result set.
Please, call mysqli_more_results()/mysqli::more_results() to check whether
to call this function/method in php shell code on line 1

覆盖子类中的方法以将不同数量的参数传递给其父类中的同一方法

Overriding a method in a subclass to take a different number of arguments to the same method in its parent

php > class A           { public function foo ($x) {} }
php > class B extends A { public function foo () {} }
PHP Strict Standards:  Declaration of B::foo() should be compatible with
A::foo($x) in php shell code on line 1
php > class C extends A { public function foo ($x, $y) {} }
PHP Strict Standards:  Declaration of C::foo() should be compatible with
A::foo($x) in php shell code on line 1

在特征和使用它的类中以兼容方式声明相同的属性.这个实际上很好文档化:

如果一个trait定义了一个属性，那么一个类就不能定义一个同名的属性，否则会报错.如果类定义兼容(相同的可见性和初始值)，则为 E_STRICT，否则为致命错误.

If a trait defines a property then a class can not define a property with the same name, otherwise an error is issued. It is an E_STRICT if the class definition is compatible (same visibility and initial value) or fatal error otherwise.

<?php
trait PropertiesTrait {
    public $same = true;
    public $different = false;
}

class PropertiesExample {
    use PropertiesTrait;
    public $same = true; // Strict Standards
    public $different = true; // Fatal error
}
?>

严格模式警告示例:

php > trait PropertiesTrait {
php {     public $same = true;
php { }
php > class PropertiesExample {
php {     use PropertiesTrait;
php {     public $same = true;
php { }
PHP Strict Standards:  PropertiesExample and PropertiesTrait define the
same property ($same) in the composition of PropertiesExample. This might
be incompatible, to improve maintainability consider using accessor
methods in traits instead. Class was composed in php shell code on line 4

静态调用非静态方法

Calling a non-static method statically

php > class Foo { function bar() {} }
php > Foo::bar();
PHP Strict Standards:  Non-static method Foo::bar() should not be called
statically in php shell code on line 1

非静态地引用静态属性

Referring to a static property non-statically

php > class Cow { static public $noise = 'moo'; }
php > $cow = new Cow;
php > $cow->noise = "MOOOOO";
PHP Strict Standards:  Accessing static property Cow::$noise as non static
in php shell code on line 1

直接传递函数调用的结果通过引用.

php > function foo () { return 1; }
php > function bar (&$some_arg) {} 
php > bar(foo());
PHP Strict Standards:  Only variables should be passed by reference in php
shell code on line 1
php > $var = &foo();
PHP Strict Standards:  Only variables should be assigned by reference in
php shell code on line 1

请注意，通过引用传递其他非变量(如文字或常量)是致命错误，而不是 E_STRICT

Note that passing other non-variables by reference, like literals or constants, is a fatal error instead of an E_STRICT

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