rfc:fallback-to-root-scope-deprecation
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rfc:fallback-to-root-scope-deprecation [2018/02/03 07:49] – wesnetmo | rfc:fallback-to-root-scope-deprecation [2018/02/03 16:20] – wesnetmo | ||
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===== Introduction ===== | ===== Introduction ===== | ||
- | Fallback to global scope allow users to access | + | Fallback to global scope allows namespaces |
- | At the time the feature was introduced, there was no `use function|const foo` syntax available | + | <code php> |
- | today, authors that really hate writing '' | + | namespace Bar; |
+ | strlen(); | ||
+ | // first tries to call \Bar\strlen() | ||
+ | // if not found, fallbacks to \strlen() | ||
+ | </ | ||
This feature causes more harm than good, since it prevents PHP from implementing **in a sensible manner** long-requested features like function autoloading. Additionally, | This feature causes more harm than good, since it prevents PHP from implementing **in a sensible manner** long-requested features like function autoloading. Additionally, | ||
Line 18: | Line 22: | ||
===== Proposal ===== | ===== Proposal ===== | ||
- | This RFC proposes to deprecate the fallback to root scope, by emitting a '' | + | This RFC proposes to deprecate the fallback to root scope, by emitting a deprecation notice, e.g.: |
< | < | ||
Line 25: | Line 29: | ||
</ | </ | ||
- | It also proposes, considered the entity of the change, that the " | + | It also proposes, considered the entity of the change, that the " |
In fact, if the feature is removed and autoloading of functions and constants is introduced at the same time, authors that failed to update their code can easily shim it using just few lines of code: | In fact, if the feature is removed and autoloading of functions and constants is introduced at the same time, authors that failed to update their code can easily shim it using just few lines of code: | ||
Line 31: | Line 35: | ||
<code php> | <code php> | ||
// Fallback to global scope shim | // Fallback to global scope shim | ||
- | // This code simply | + | // This code simply |
- | register_autoloader( | + | // Note: this is just a PoC |
- | | + | autoload_register(AUTOLOAD_FUNCTION | AUTOLOAD_CONST, |
- | | + | // Assumes $namespaced is NOT prepended with \ |
- | + | // Assumes | |
- | $start = strrpos($QN, " | + | |
- | if($start === false){ return; } | + | // Find last occurrence of \ |
- | + | $offset | |
- | // e.g. " | + | |
- | $sourceNS | + | // Return if none; this is only active for namespaced symbols |
- | + | | |
- | // e.g. " | + | |
- | | + | // Fallback symbol' |
- | + | $fallback | |
- | | + | |
- | | + | // Alias the function |
- | | + | if($type & \AUTOLOAD_FUNCTION && |
- | | + | \function_alias($fallback, |
- | | + | |
- | namespace ' . $sourceNS . '; | + | |
- | function ' . $rootSymbol . ' | + | |
- | return | + | |
- | } | + | |
- | '); | + | |
- | }elseif( | + | |
- | ($type & AUTOLOAD_CONST) && | + | |
- | defined($rootSymbol) | + | |
- | ){ | + | |
- | eval(' | + | |
- | namespace ' . $sourceNS . '; | + | |
- | const ' . $rootSymbol . ' = \\' . $rootSymbol . '; | + | |
- | '); | + | |
- | } | + | |
} | } | ||
- | ); | + | |
+ | // Alias the constant | ||
+ | if($type & \AUTOLOAD_CONST && \defined($fallback /*, false [1] */)){ | ||
+ | \define($namespaced, | ||
+ | } | ||
+ | }); | ||
+ | |||
+ | // [1] = may not trigger autoloading from an autoloader | ||
</ | </ | ||
+ | |||
+ | However, if this RFC passes, authors should try to avoid the Notice by writing `\strlen()` or `use function {strlen, strpos};` in their code, which are **plenty of solutions covering any code style**. | ||
+ | |||
+ | ===== Migration Tools ===== | ||
+ | |||
+ | * [[https:// | ||
+ | * [[https:// | ||
+ | * [[https:// | ||
+ | * More coming soon... | ||
===== Backward Incompatible Changes ===== | ===== Backward Incompatible Changes ===== | ||
Line 82: | Line 87: | ||
===== References ===== | ===== References ===== | ||
- | @TODO link discussion | + | - [[https:// |
rfc/fallback-to-root-scope-deprecation.txt · Last modified: 2018/02/03 16:26 by wesnetmo