rfc:scalar_type_hints_v5
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rfc:scalar_type_hints_v5 [2015/02/18 20:54] – fix typo ircmaxell | rfc:scalar_type_hints_v5 [2018/10/17 11:38] (current) – Fix table align in "bool" column carusogabriel | ||
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====== PHP RFC: Scalar Type Declarations ====== | ====== PHP RFC: Scalar Type Declarations ====== | ||
- | * Version: 0.5.0 | + | * Version: 0.5.3 |
* Date: 2015-02-18 | * Date: 2015-02-18 | ||
* Author: Anthony Ferrara < | * Author: Anthony Ferrara < | ||
- | * Status: | + | * Status: |
* First Published at: http:// | * First Published at: http:// | ||
* Forked From: http:// | * Forked From: http:// | ||
Line 9: | Line 9: | ||
===== Summary ===== | ===== Summary ===== | ||
- | This RFC proposes the addition of four new type declarations for scalar types: '' | + | This RFC proposes the addition of four new type declarations for scalar types: '' |
This RFC further proposes the addition of a new optional per-file directive, '' | This RFC further proposes the addition of a new optional per-file directive, '' | ||
Line 20: | Line 20: | ||
* '' | * '' | ||
* '' | * '' | ||
+ | * aliases are removed ('' | ||
===== Details ===== | ===== Details ===== | ||
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==== Scalar Type Declarations ==== | ==== Scalar Type Declarations ==== | ||
- | No new reserved words are added. The names '' | + | No new reserved words are added. The names '' |
The new userland scalar type declarations are implemented internally by calling the Fast Parameter Parsing API functions. | The new userland scalar type declarations are implemented internally by calling the Fast Parameter Parsing API functions. | ||
Line 124: | Line 125: | ||
The table shows which types are accepted and converted for scalar type declarations. '' | The table shows which types are accepted and converted for scalar type declarations. '' | ||
- | ^ Type declaration | + | ^ Type declaration |
- | ^ '' | + | ^ '' |
- | ^ '' | + | ^ '' |
- | ^ '' | + | ^ '' |
- | ^ '' | + | ^ '' |
< | < | ||
Line 144: | Line 145: | ||
These strict type checking rules are used for userland scalar type declarations, | These strict type checking rules are used for userland scalar type declarations, | ||
- | The one exception is that [[http:// | + | The one exception is that [[http:// |
<file php widening.php> | <file php widening.php> | ||
Line 157: | Line 158: | ||
</ | </ | ||
- | In this case, we're passing an '' | + | In this case, we're passing an '' |
+ | |||
+ | No other conversions are allowed. | ||
+ | |||
+ | ==== Error Handler Behavior In Strict Mode ==== | ||
+ | |||
+ | Currently it's possible to bypass error check failures using an error handler: | ||
+ | |||
+ | <file php error_handler_fail.php> | ||
+ | <?php | ||
+ | declare(strict_types=1); | ||
+ | set_error_handler(function() { | ||
+ | return true; | ||
+ | }); | ||
+ | |||
+ | function foo(int $abc) { | ||
+ | var_dump($abc); | ||
+ | } | ||
+ | foo(" | ||
+ | ?> | ||
+ | </ | ||
+ | |||
+ | This would defeat the purpose of strict typing. | ||
+ | |||
+ | Therefore, this RFC proposes to bypass function execution in strict mode if there' | ||
===== Example ===== | ===== Example ===== | ||
Line 244: | Line 270: | ||
} | } | ||
- | var_dump(foobar2()); | + | var_dump(foobar()); |
// Catchable fatal error: Return value of foobar() must be of the type integer, float returned | // Catchable fatal error: Return value of foobar() must be of the type integer, float returned | ||
</ | </ | ||
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No type declaration for resources is added, as this would prevent moving from resources to objects for existing extensions, which some have already done (e.g. GMP). | No type declaration for resources is added, as this would prevent moving from resources to objects for existing extensions, which some have already done (e.g. GMP). | ||
- | |||
- | For the integer declaration, | ||
===== Discussion Points ===== | ===== Discussion Points ===== | ||
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In line with [[http:// | In line with [[http:// | ||
- | It however also means that narrowing conversions (float-> | + | It however also means that narrowing conversions (float-> |
+ | |||
+ | Note: If you read the Java spec, you'll notice that it does mention narrowing conversions. It only allows them in assignment or explicit casts however. So they do not apply in the case this proposal puts forward. | ||
==== Weak Should Error On "10 Birds" Style-Strings Passed To Int Parameters ==== | ==== Weak Should Error On "10 Birds" Style-Strings Passed To Int Parameters ==== | ||
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=== Current Position === | === Current Position === | ||
- | There are two problems with using one of the proposed alternates: | + | The declare system was designed precisely for this style of engine switch. Additionally, |
- | * All are generic " | + | There are also problems with using each of the proposed alternates: |
- | * All require either re-interpreting existing syntax or creating new and foreign syntax. | + | |
- | The declare system was designed precisely for this style of engine switch. Additionally, | + | * ''<? |
+ | |||
+ | This is new syntax, which is potentially ambiguous around what " | ||
+ | |||
+ | Additionally, | ||
+ | |||
+ | * ''<? | ||
+ | |||
+ | This opens the door for potential code disclosure vulnerability if run on an earlier version of PHP (since the ''<? | ||
+ | |||
+ | * '' | ||
+ | |||
+ | Re-using namespaces to affect runtime is weird. Not to mention what's the expected behavior of block mode: | ||
+ | |||
+ | <file php use_strict.php> | ||
+ | <?php | ||
+ | namespace Foo { | ||
+ | use strict; | ||
+ | } | ||
+ | |||
+ | namespace { | ||
+ | bar(); | ||
+ | } | ||
+ | ?> | ||
+ | </ | ||
+ | |||
+ | is bar() called | ||
+ | |||
+ | * ''<? | ||
+ | |||
+ | Comments should not affect runtime behavior. HHVM uses it as they need to affect behavior while remaining compatible with PHP. We do not have that problem. | ||
+ | |||
+ | * '' | ||
+ | |||
+ | Which had a number of people against it, with arguments about the odd behavior of declare in blocks, etc. It does not respect scope, so calling it in one function would transparently effect all future | ||
+ | |||
+ | * '' | ||
+ | |||
+ | <file php strict_namespace.php> | ||
+ | <?php | ||
+ | strict namespace Foo { | ||
+ | |||
+ | } | ||
+ | |||
+ | namespace { | ||
+ | bar(); | ||
+ | } | ||
+ | ?> | ||
+ | </ | ||
+ | |||
+ | This has the same issues as use strict above. However, it also seems to imply that the namespace is strict, where it's only the declarations in the file that are. | ||
==== Why Not Allow Block-Mode For Declare ==== | ==== Why Not Allow Block-Mode For Declare ==== | ||
Line 516: | Line 591: | ||
Allowing strict " | Allowing strict " | ||
- | Therefore, this proposal explicitly disallows changing the type mode anywhere within the file except the first line. Since the first line is the only allowed type change, block mode does not make sense (as there could only ever be a single block in the file). | + | Therefore, this proposal explicitly disallows changing the type mode anywhere within the file except the first line. Since the first line is the only allowed type change, block mode does not make sense (as there could only ever be a single block in the file). |
+ | |||
+ | Additionally, | ||
==== Internal Functions Do Not Have Declared Return Types ==== | ==== Internal Functions Do Not Have Declared Return Types ==== | ||
Line 542: | Line 619: | ||
Currently, there' | Currently, there' | ||
+ | ==== Why Not Add An INI Setting For Default Mode ==== | ||
+ | |||
+ | It's been asked for the ability to switch the default mode from " | ||
+ | |||
+ | === Current Position === | ||
+ | |||
+ | This proposal takes the opinion that behavior modifying switches like ini settings are a death-toll to portability and well designed languages should not change behavior based on " | ||
+ | |||
+ | ==== Type Aliases Should Not Be Supported ==== | ||
+ | |||
+ | The original proposal had two additional type aliases supported: '' | ||
+ | |||
+ | === Current Position === | ||
+ | |||
+ | This proposal takes the stance that there should be one obvious type. Therefore, no aliases are supported. | ||
+ | |||
+ | ==== This Proposal Should Have Multiple Vote Options ==== | ||
+ | |||
+ | Several people have proposed that this proposal should have 3 or 4 vote options (No, Weak Only, Strict Only, Weak + Strict). | ||
+ | |||
+ | === Current Position === | ||
+ | https:// | ||
+ | This is not a two-part proposal. The proposal is of a unified system that was designed to work together. As such, neither part (weak-only or strict-only) is designed to stand on its own without the other part. | ||
+ | |||
+ | Therefore, it only makes sense to vote on this proposal as a whole. Therefore, the voting options this RFC will present will be: '' | ||
+ | |||
+ | ==== Integer Overflow To Float Behavior ==== | ||
+ | |||
+ | Currently, certain integer operations will result in an overflow to a floating point value. Consider the following code: | ||
+ | |||
+ | <file php integer_overflow.php> | ||
+ | <?php | ||
+ | var_dump(2 ** 61); // int(2305843009213693952) | ||
+ | var_dump(2 ** 64); // float(1.844674407371E+19) | ||
+ | </ | ||
+ | |||
+ | This can result in an error when passing the result of an operation to another function expecting an integer. | ||
+ | |||
+ | There are two prime ways of handling this issue: | ||
+ | |||
+ | * Allow '' | ||
+ | * Error at runtime. | ||
+ | |||
+ | === Current Position === | ||
+ | |||
+ | Allowing for " | ||
+ | |||
+ | Therefore, a runtime error that the overflow occurred is the most appropriate thing to do. | ||
+ | |||
+ | Therefore, the position of this proposal is that overflow situations should generate a runtime error. If you need overflow safety, you should be using a library like GMP. | ||
===== Backward Incompatible Changes ===== | ===== Backward Incompatible Changes ===== | ||
- | '' | + | '' |
Because the weak type-checking rules for scalar declarations are quite permissive in the values they accept and behave similarly to PHP's type juggling for operators, it should be possible for existing userland libraries to add scalar type declarations without breaking compatibility. | Because the weak type-checking rules for scalar declarations are quite permissive in the values they accept and behave similarly to PHP's type juggling for operators, it should be possible for existing userland libraries to add scalar type declarations without breaking compatibility. | ||
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===== Proposed PHP Version(s) ===== | ===== Proposed PHP Version(s) ===== | ||
- | This is proposed for the next PHP x, currently PHP 7. The acceptance for said version will depend on timing | + | This proposal targets |
===== RFC Impact ===== | ===== RFC Impact ===== | ||
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As this is a language change, this RFC requires a 2/3 majority to pass. | As this is a language change, this RFC requires a 2/3 majority to pass. | ||
+ | |||
+ | <doodle title=" | ||
+ | * Yes | ||
+ | * No | ||
+ | </ | ||
+ | |||
+ | This vote is opened on February 26th, 2015 and will close March 16th at 21:00 UTC as announced on list. | ||
===== Patches and Tests ===== | ===== Patches and Tests ===== | ||
Line 597: | Line 731: | ||
===== Changelog ===== | ===== Changelog ===== | ||
+ | * v0.5.3 Change version target back and add line about bypassing function execution on type error in strict mode | ||
+ | * v0.5.2 Change version target | ||
+ | * v0.5.1 Remove aliases from proposal | ||
* v0.5 Fork from Andrea' | * v0.5 Fork from Andrea' |
rfc/scalar_type_hints_v5.txt · Last modified: 2018/10/17 11:38 by carusogabriel