PHP7.1 Feature/Incompatible 升級注意事項
目錄
PHP 從 7 的問世後，後續更新速度很快， 讀了一下 7.0 到 7.1 PHP 官方升級文件 做個筆記， 這邊列出對於開發常見項目的 Feature 做簡述:
Features
Symmetric array destructuring
- 用一個 foreach 支援印出二維陣列
- 可以用
list以及 shorthand[]兩種表示法
<?php
$data = [
[1, 'Tom'],
[2, 'Fred'],
];
// list() style
list($id1, $name1) = $data[0];
// [] style
[$id1, $name1] = $data[0];
// list() style
foreach ($data as list($id, $name)) {
// logic here with $id and $name
}
// [] style
foreach ($data as [$id, $name]) {
// logic here with $id and $name
}Class constant visibility
- Class 內的 constant 可以決定 Visibility
<?php
class ConstDemo
{
const PUBLIC_CONST_A = 1;
public const PUBLIC_CONST_B = 2;
protected const PROTECTED_CONST = 3;
private const PRIVATE_CONST = 4;
}
// public / protected / private
Multi catch exception handling
- 支援在同一個 catch 內捕捉多組 Exception type
<?php
try {
// some code
} catch (FirstException | SecondException $e) {
// handle first and second exceptions
}Support for keys in list()
- 可以在 array 的表示式內如
list()或shorthand []指定 key 來賦值
<?php
$data = [
["id" => 1, "name" => 'Tom'],
["id" => 2, "name" => 'Fred'],
];
// list() style
list("id" => $id1, "name" => $name1) = $data[0];
// [] style
["id" => $id1, "name" => $name1] = $data[0];
// list() style
foreach ($data as list("id" => $id, "name" => $name)) {
// logic here with $id and $name
}
// [] style
foreach ($data as ["id" => $id, "name" => $name]) {
// logic here with $id and $name
}Support for negative string offsets
- String 的 index offset 支援負數
<?php
var_dump("abcdef"[-2]);
var_dump(strpos("aabbcc", "b", -3));string (1) "e"
int(3)Backward incompatible changes
Throw on passing too few function arguments
- 以前如果沒有傳入對應的參數會噴出 Warning 做提示，7.1 升級成更嚴謹的 Error exception.
<?php
function test($param){}
test();
危險
Fatal error: Uncaught ArgumentCountError: Too few arguments to function test(), 0 passed in %s on line %d and exactly 1 expected in %s:%d
error_log changes with syslog value
The empty index operator is not supported for strings anymore
- If the error_log ini setting is set to syslog, the PHP error levels are mapped to the syslog error levels
The empty index operator is not supported for strings anymore
- 替 string 設置空的 index operator (e.g. $str[] = $x) 現在將會噴 fatal error
<?php
$foo = '';
$foo[] = 'bar';PHP Fatal error: Uncaught Error: [] operator not supported for strings7.0 到 7.1 的異動實在是有點多，還是看官網吧 ╮(╯◇╰)╭