Download to read offline
![Attributes: syntax TBD Using doc comments /** @Entity */ class User { /** * @Id * @Column(type="integer") * @GenerateValue */ private $id; } Attributes with Rust-like syntax use DoctrineORMAttributes as ORM; #[ORMEntity] class User { #[ORMId] #[ORMColumn("integer")] #[ORMGenerateValue] private $id; } 15 Class name Constructor argument](https://image.slidesharecdn.com/php8-200808143600/75/PHP-8-Process-Fixing-Insanity-15-2048.jpg)
![Attributes $rc = new ReflectionClass (User::class); foreach ($rc->getAttributes() as $attr) { var_dump($attr->getName()); // => "DoctrineORMAttributesEntity" var_dump($attr->getArguments()); // => [] var_dump($attr->newInstance()); // object(DoctrineORMAttributesEntity) ... } 17 Attribute validation happens here](https://image.slidesharecdn.com/php8-200808143600/75/PHP-8-Process-Fixing-Insanity-17-2048.jpg)
![Union types: weak and strict mode declare(strict_types=0); function test(int|float|bool $arg) { var_dump($arg); } test(45); // int(45) test(45.8); // float(45.8) test("45"); // int(45) test("45.8"); // float(45.8) test(""); // bool(false) test("X"); // bool(true) test([]); // TypeError declare(strict_types=1); function test(int|float|bool $arg) { var_dump($arg); } test(45); // int(45) test(45.8); // float(45.8) test("45"); // TypeError test("45.8"); // TypeError test(""); // TypeError test("X"); // TypeError test([]); // TypeError 24](https://image.slidesharecdn.com/php8-200808143600/75/PHP-8-Process-Fixing-Insanity-24-2048.jpg)
![mixed Distinguish between: • Type is missing because it wasn’t yet added • This function accepts/returns anything 25 function var_dump(mixed $value, mixed ...$value): void {} function unserialize(string $value, array $options = []): mixed {}](https://image.slidesharecdn.com/php8-200808143600/75/PHP-8-Process-Fixing-Insanity-25-2048.jpg)
![Notable BC breaks: locale PHP 7.4 setlocale(LC_ALL, "de_DE"); $f = 3.14; (string) $f; // 3,14 strval($f); // 3,14 print_r($f); // 3,14 var_dump($f); // float(3,14) debug_zval_dump($f); // float(3,14) settype($f, "string"); // 3,14 implode([$f]); // 3,14 xmlrpc_encode($f); // 3,14 PHP 8.0 setlocale(LC_ALL, "de_DE"); $f = 3.14; (string) $f; // 3.14 strval($f); // 3.14 print_r($f); // 3.14 var_dump($f); // float(3.14) debug_zval_dump($f); // float(3.14) settype($f, "string"); // 3.14 implode([$f]); // 3.14 xmlrpc_encode($f); // 3.14 37](https://image.slidesharecdn.com/php8-200808143600/75/PHP-8-Process-Fixing-Insanity-37-2048.jpg)
![Warning promotion: what benefits? var_dump(strlen([])); // Warning: strlen() expects parameter 1 to be string, array given // NULL function strlen(string $str): int|null {} var_dump(array_fill(0, -100, 'foobar')); // Warning: array_fill(): Number of elements can't be negative // bool(false) function array_fill(int $start_key, int $num, mixed $val): array|false {} 39](https://image.slidesharecdn.com/php8-200808143600/75/PHP-8-Process-Fixing-Insanity-39-2048.jpg)
![Warning promotion: what benefits? var_dump(strlen([])); // Fatal error: Uncaught TypeError: strlen(): // Argument #1 ($str) must be of type string, array given function strlen(string $str): int {} var_dump(array_fill(0, -100, 'foobar')); // Fatal error: Uncaught ValueError: array_fill(): // Argument #2 ($num) must be greater than or equal to 0 function array_fill(int $start_key, int $num, mixed $val): array {} 40](https://image.slidesharecdn.com/php8-200808143600/75/PHP-8-Process-Fixing-Insanity-40-2048.jpg)
![String to number comparisons $validValues = ["foo", "bar", "baz"]; $value = 0; var_dump(in_array($value, $validValues)); // bool(true) WTF??? var_dump(0 == "foo"); // bool(true) WTF??? Are always performed numerically 46](https://image.slidesharecdn.com/php8-200808143600/75/PHP-8-Process-Fixing-Insanity-46-2048.jpg)
PHP 8: Process & Fixing Insanity
- 1. POINT TECHNIQUE PHP 8:Process & Fixing Insanity
- 2. George Peter Banyard ●Mathematics student at Imperial College London ● Currently hired by The Coding Machine to work on php-src, i.e. the PHP Engine ● Find me on Twitter and elsewhere @Girgias ● https://gpb.moe 2 Me at 3AM realising I need a photo for the presentation
- 3. How I gotinvolved with the PHP project • French translation PHP documentation • PHP internal mailing list • Proposed the “Deprecate PHP Short open tags” PHP RFC • Started tinkering with PHP’s source code • PoC: declare statement which promote warnings to Exceptions • Made multiple patches • php-src VCS karma granted 3
- 4. PHP a trulyopen source language: PHP RFCs A PHP RFC is a proposal which affects the PHP engine: Behaviour change, feature addition, deprecations, extensions Anyone can propose a PHP RFC, from QoL to Advanced feature • Minimum 2 week discussion period • 2 week voting period • Everyone with a PHP VCS account can vote (1000+ people!) PHP 8 is 30+ accepted RFCs from over 15 people Many more which have been declined See them all at: https://wiki.php.net/rfc 4
- 5. QoL Trailing commas inparameter list and closure use list $longArgs_longVars = function ( $longArgument, $longerArgument , $muchLongerArgument , ) use ( $longVar1, $longerVar2, $muchLongerVar3 , ) { // body }; 5 Allowed!
- 6. QoL ::class notation onvariables $class = $object::class; // Identical to $class = get_class($object); DateTimeInterface::createFromInterface public static function createFromInterface (DateTimeInterface $object): DateTime public static function createFromInterface (DateTimeInterface $object): DateTimeImmutable 6
- 7. QoL Non-capturing catches try { doStuffWhichMightThrow(); } catch (Exception) { // The intention is clear: exception details are irrelevant echo "Some error message" ; } Null safe operator ?-> $country = null; if ($session !== null) { $user = $session->user; if ($user !== null) { $address = $user->getAddress(); if ($address !== null) { $country = $address->country; } } } // do something with $country 7 $country = $session?->user?->getAddress()?-> country; // do something with $country Becomes
- 8. QoL JSON Extension alwaysenabled Stable sorting Functions: function str_contains(string $haystack, string $needle): bool {} function str_starts_with (string $haystack, string $needle): bool {} function str_ends_with(string $haystack, string $needle): bool {} function fdiv(float $dividend, float $divisor): float {} // IEEE 754 semantics 8
- 9.
- 10. Just In TimeCompiler (JIT) • Compiles PHP code into machine language for x86 (Intel/AMD) • Performance gain for CPU bounded (i.e. math) • ⚠ May lead to performance loss on more “traditional” code Part of OpCache: • opcache.jit=on • opache.jit_buffer_size=128M 10
- 11. Match Similar to theswitch statement Major differences: • Exhaustive, if value not matched throws UnhandledMatchError • Uses strict comparison (===) • No fallthrough • Returns a value • Match condition can be any expression • Match statement must be a single expression (like arrow functions) 11
- 12. Match: a simpleexample PHP 7.x switch (1) { case 0: $result = 'Foo'; break; case 1: $result = 'Bar'; break; case 2: case 3: $result = 'Baz'; break; default: $result = 'FooBar'; break; } echo $result; //> Bar PHP 8.0 echo match (1) { 0 => 'Foo', 1 => 'Bar', 2, 3 => 'Baz', default => 'FooBar', }; //> Bar 12
- 13. Match: complex example echomatch ($x) { 3, 5 => throw new Exception('Cannot be 3 or 5'), foo() => "foo", $this->bar() => "bar() check", // bar() isn't called if foo() matched with $x }; If nothing is matched a UnhandledMatchError is thrown 13 Possible because throw is an expression in PHP 8
- 14. Constructor promotion PHP 7.x classPoint { public float $x; public float $y; public float $z; public function __construct( float $x = 0.0, float $y = 0.0, float $z = 0.0, ) { $this->x = $x; $this->y = $y; $this->z = $z; } } PHP 8.0 class Point { public function __construct( public float $x = 0.0, public float $y = 0.0, public float $z = 0.0, ) { } } 14
- 15. Attributes: syntax TBD Usingdoc comments /** @Entity */ class User { /** * @Id * @Column(type="integer") * @GenerateValue */ private $id; } Attributes with Rust-like syntax use DoctrineORMAttributes as ORM; #[ORMEntity] class User { #[ORMId] #[ORMColumn("integer")] #[ORMGenerateValue] private $id; } 15 Class name Constructor argument
- 16. Attributes: syntax TBD Hack-style useDoctrineORMAttributes as ORM; <<ORMEntity>> class User { <<ORMId>> <<ORMColumn("integer")>> <<ORMGenerateValue>> private $id; } @@-style use DoctrineORMAttributes as ORM; @@ORMEntity class User { @@ORMId @@ORMColumn("integer") @@ORMGenerateValue private $id; } 16
- 17. Attributes $rc = newReflectionClass (User::class); foreach ($rc->getAttributes() as $attr) { var_dump($attr->getName()); // => "DoctrineORMAttributesEntity" var_dump($attr->getArguments()); // => [] var_dump($attr->newInstance()); // object(DoctrineORMAttributesEntity) ... } 17 Attribute validation happens here
- 18. Named arguments // Usingpositional arguments: array_fill(0, 100, 50); // Using named arguments: array_fill(start_index: 0, num: 100, value: 50); array_fill(value: 50, num: 100, start_index: 0); // Skip default values htmlspecialchars ($string, double_encode: false); // Same as htmlspecialchars ($string, ENT_COMPAT|ENT_HTML401, 'UTF-8', false); Combined with Constructor promotion: Object Initialization Named arguments work with attributes Renaming internal function args and matching the documentation 18
- 19. Type System Improvements Uniontypes, mixed, static return, internal functions, opaque objects 19
- 20. Existing union types •?Type = Type|null • iterable = Traversable|array 20
- 21. Union types PHP 7.4 classNumber { /** @var int|float */ private $number; /** @return float|int */ public function getNumber() { return $this->number; } /** @param float|int $number */ public function setNumber($number): void { $this->number = $number; } } PHP 8.0 class Number { private float|int $number; public function getNumber(): float|int { return $this->number; } public function setNumber(float|int $number): void { $this->number = $number; } } 21
- 22. Union types: exotictypes function shell_exec(string $command): string|false|null {} 22 Common in standard library ?Type is a shorthand to Type|null
- 23. Union types: handlingin weak mode In weak mode the handling is a bit tricky: • Type is part of the union • Scalars are coerced to int, float, string, bool in order of preference 23
- 24. Union types: weakand strict mode declare(strict_types=0); function test(int|float|bool $arg) { var_dump($arg); } test(45); // int(45) test(45.8); // float(45.8) test("45"); // int(45) test("45.8"); // float(45.8) test(""); // bool(false) test("X"); // bool(true) test([]); // TypeError declare(strict_types=1); function test(int|float|bool $arg) { var_dump($arg); } test(45); // int(45) test(45.8); // float(45.8) test("45"); // TypeError test("45.8"); // TypeError test(""); // TypeError test("X"); // TypeError test([]); // TypeError 24
- 25. mixed Distinguish between: • Typeis missing because it wasn’t yet added • This function accepts/returns anything 25 function var_dump(mixed $value, mixed ...$value): void {} function unserialize(string $value, array $options = []): mixed {}
- 26. mixed // For argumenttypes: // No type is equivalent to mixed class Parent { public function foo(mixed $arg) {} } class Child extends Parent { public function foo($arg) {} } // For return types: // No type means mixed|void class Parent { public function foo(): mixed {} } class Child extends Parent { public function foo() {} } 26 Forbidden: widening type
- 27. Static return type //Named constructor class ParentClass { public static function createFromWhatever($whatever): static { return new static($whatever); } } class ChildClass extends ParentClass {} var_dump(ChildClass::createFromWhatever(null)); //object(ChildClass)#1 (0) { //} 27
- 28. Static return type //Named constructor class ParentClass { public static function createFromWhatever($whatever): static { return new self($whatever); } } class ChildClass extends ParentClass {} var_dump(ChildClass::createFromWhatever(null)); // TypeError: ParentClass::createFromWhatever(): Return value must be of type ChildClass, ParentClass returned 28 self vs static
- 29. PHP Stubs PHP stubsspecify signature for internal functions/methods ● Becomes the source of truth ● Generates C code function registration with arg info ● Data is now available through Reflection ○ ReflectionFunction::getReturnType(); ○ ReflectionParameter::getType(); ○ ReflectionParameter::getDefaultValue(); 29
- 30. PHP Stubs: whatit means for you // Stub class DateTime implements DateTimeInterface { /** @return DateTime */ public function add(DateInterval $interval) { } } // Your code class MyDateTime extends DateTime { public function add(DateInterval $interval): DateTime { } } 30 Now allowed! A real return type would force all extending classes to specify it due to covariance, BC Break!
- 31. Resource to objectconversion Why? • Better type safety • Better internal support • Long term: convert all resources to objects • That’s why there is no ‘resource’ type • Opaque objects with no API • Oriented Object API might be added later 31
- 32. Resource to objectconversion Notable conversions in PHP 8 • GdImage • Curl • ZIP • Inflate/Deflate from Zlib • OpenSSL (W.I.P.) 32
- 33. Resource to objectconversion PHP 7.x only $curlHandler = curl_init($url); if (!is_resource($curlHandler)) { throw new Exception(); } PHP 7.x and PHP 8.0 $curlHandler = curl_init($url); if ($curlHandler !== false) { throw new Exception(); } 33 This is an Object in case of success or false on failure
- 34.
- 35. Notable BC breaks:error handling • E_ALL by default • Might need to adjust error handler and INI settings • PDO now throws exception by default • Might break application not using PDO’s throw mode • Can de disabled by passing: PDO::ERRMODE_SILENT during construction 35
- 36. Notable BC breaks:locale • Default locale is now always the C locale • Float to string conversions are now locale independent 36
- 37. Notable BC breaks:locale PHP 7.4 setlocale(LC_ALL, "de_DE"); $f = 3.14; (string) $f; // 3,14 strval($f); // 3,14 print_r($f); // 3,14 var_dump($f); // float(3,14) debug_zval_dump($f); // float(3,14) settype($f, "string"); // 3,14 implode([$f]); // 3,14 xmlrpc_encode($f); // 3,14 PHP 8.0 setlocale(LC_ALL, "de_DE"); $f = 3.14; (string) $f; // 3.14 strval($f); // 3.14 print_r($f); // 3.14 var_dump($f); // float(3.14) debug_zval_dump($f); // float(3.14) settype($f, "string"); // 3.14 implode([$f]); // 3.14 xmlrpc_encode($f); // 3.14 37
- 38. Notable BC breaks:warning promotion • Consistent TypeError for internal functions • This allows the PHP Stubs to exist • LSP errors always throw (type safety) • Engine notices and warnings reclassified • Complete list at: https://wiki.php.net/rfc/engine_warnings • ValueErrors • A good attempt to list all affected functions: https://nahan.fr/nouvelle-erreur-valueerror-dans-php-8/ These only affect programming errors Handling the error is nonsensical, code needs to be fixed 38
- 39. Warning promotion: whatbenefits? var_dump(strlen([])); // Warning: strlen() expects parameter 1 to be string, array given // NULL function strlen(string $str): int|null {} var_dump(array_fill(0, -100, 'foobar')); // Warning: array_fill(): Number of elements can't be negative // bool(false) function array_fill(int $start_key, int $num, mixed $val): array|false {} 39
- 40. Warning promotion: whatbenefits? var_dump(strlen([])); // Fatal error: Uncaught TypeError: strlen(): // Argument #1 ($str) must be of type string, array given function strlen(string $str): int {} var_dump(array_fill(0, -100, 'foobar')); // Fatal error: Uncaught ValueError: array_fill(): // Argument #2 ($num) must be greater than or equal to 0 function array_fill(int $start_key, int $num, mixed $val): array {} 40
- 41. Warning promotion: whatstays the same var_dump(fopen("does_not_exist.txt", "r'")); // Warning: fopen(does_not_exist.txt): Failed to open stream: Operation not permitted // bool(false) 41 Actually I lied, this is capitalized in PHP 8.0
- 42. Numeric strings Numeric strings:“12”, “15.6”, “5e6”, “ 10” Leading-numeric strings: “10 ”, “14abc” Non-numeric strings: “string” 42 Emit E_NOTICE "A non well formed numeric value encountered" Leading white-spaces are considered more numeric than trailing white-spaces
- 43. Numeric strings Where arenumeric strings used? • Type declarations in weak mode • is_numeric() function • String to string comparisons • Arithmetic and bitwise operations • Increment/Decrement operation (++ and --) • String offsets • NOT array offsets, they have different semantics 43
- 44. Numeric strings: bringingback sanity All details: Saner Numeric Strings RFC: https://wiki.php.net/rfc/saner-numeric-strings TL;DR: • E_NOTICE "A non well formed numeric value encountered" to E_WARNING "A non-numeric value encountered" with value preserved • Other E_WARNINGs promoted to TypeError 44
- 45. Numeric strings: bringingback sanity PHP 7.4 function foo(int $i) { var_dump($i); } foo(" 123"); // int(123) foo("123 "); // int(123) with E_NOTICE foo("123abc"); // int(123) with E_NOTICE var_dump(123 + "123 ");// int(246) with E_NOTICE var_dump(123 + "123abc");// int(246) with E_NOTICE var_dump(123 + "str"); // int(123) with E_WARNING var_dump("123" == " 123"); // bool(true) var_dump("123" == "123 "); // bool(false) var_dump("123" == "123abc"); // bool(false) PHP 8.0 function foo(int $i) { var_dump($i); } foo(" 123"); // int(123) foo("123 "); // int(123) foo("123abc"); // int(123) with E_WARNING var_dump(123 + "123 "); var_dump(123 + "123abc"); // int(246) with E_WARNING var_dump(123 + "str"); // TypeError var_dump("123" == " 123"); // bool(true) var_dump("123" == "123 "); // bool(true) var_dump("123" == "123abc"); // bool(false) 45
- 46. String to numbercomparisons $validValues = ["foo", "bar", "baz"]; $value = 0; var_dump(in_array($value, $validValues)); // bool(true) WTF??? var_dump(0 == "foo"); // bool(true) WTF??? Are always performed numerically 46
- 47. String to numbercomparisons: sanity at last Comparison | PHP 7.4 | PHP 8.0 ---------------------------------- 0 == "0" | true | true 0 == "0.0" | true | true 0 == "foo" | true | false 0 == "" | true | false 42 == " 42" | true | true 42 == "42 " | true | true 42 == "42foo" | true | false 47
- 48. Other BC breaks: •Precedence of the concatenation operator . • Default values before mandatory ones are now deprecated • final on private methods (except on __construct()) • Treat namespaces names as a single token • Full list in the UPGRADING document https://github.com/php/php-src/blob/master/UPGRADING 48
- 49. Performance gain • strtolower()now uses a SIMD implementation when using the "C" LC_CTYPE locale • array_slice() on an array without gaps will no longer scan the whole array to find the start offset. This may significantly reduce the runtime of the function with large offsets and small lengths • Removal of old style constructor in PHP 8.0 seems to yield 20% performance increase in WordPress https://idk.dev/improving-performance-of-php-for-arm64-and-im pact-on-amazon-ec2-m6g-instances/ 49
- 50. Micro-optimizations DISCLAIMER: I have nottested the performance of the following changes, these are just tidbits I remember which have been committed to php-src 50
- 51. Micro-optimizations • Optimize $x=== null into is_null($x) https://github.com/php/php-src/commit/36afe4e39ec724eab19c54c1492db030721d0ec1 • Yes is_null() generated a “better” TYPE_CHECK OpCode • Optimize instanceof checks https://github.com/php/php-src/commit/c858d17f06179aa25f6e8aa06965313fd519d8e9 https://github.com/php/php-src/commit/c63a0e005abe4b00ab097dc47ca53d20788a6361 • Optimize int === int/float === float https://github.com/php/php-src/commit/e8525c2f68d938162af055fd843239778a13565d • Weirdly enough by copying the implementation of == • Optimize is_scalar($x) into a TYPE_CHECK opcode https://github.com/php/php-src/commit/937fa6d9e2f38b5e70a2a510b87ce0be4839a404 • Optimize return type checking https://github.com/php/php-src/commit/0bac7854779595603e0431521c60744665641734 51
- 52.