Hey,
Here some perspective on this from the Composer side of things. To the
best of my knowledge the Composer autoloader is the default autoloader
used by most PHP projects at this point except for WordPress. I am sure
there are a few more outliers and people using custom autoloaders in
addition of, or instead of the Composer-generated one, but generally
speaking it has supplanted many custom implementations in frameworks
over the years.
First of all big +1 here, if we can make things faster for non-preloaded
workloads it's great. The autoloader is definitely a big fixed
"infrastructure cost" in many such apps currently, and I don't think we
can squeeze any more perf from userland.
On 15/03/2021 19:32, Mark Randall wrote:
On 15/03/2021 17:59, Levi Morrison via internals wrote:
IMO, these should be the defined case of the class, or we should be
insensitive about it. It's one thing that our symbols are case
insensitive; it is wholly another to _require_ it for this feature by
requiring lowercase names. I assume there is some motivation for this;
I would like to hear it.
EG(class_table) is stored lowercase, the case of the class name itself
is only known once it has been found which could only occur after the
autoloader has run.
By forcing lowercase we have a single key to lookup for any variation,
without it we would have to either match the case exactly (which would
be different from how internals currently works) or would have to
iterate over every item in the classmap array each time, performing
case a insensitive comparisons on every key until one was found, or in
the worst case, the entire set.
- The Composer ClassLoader [1] uses a case-sensitive classmap which
overall has not caused major issues except when people do class_exists
or new calls with the wrong case. That said, if we were to support this
new API we would for sure be able to generate a lowercased classmap, we
just haven't done it until now because spl_register_autoload calls the
callback with the original case, and having to lowercase the passed
class name on every call seemed wasteful. If internals already does this
anyway that sounds fine by me.
- It also uses `include` vs the proposed require_once in this RFC. I am
not entirely sure what the implications are here, nor if there are still
performance differences to one over the other, but IIRC we do include
because it's the fastest, and as a class never gets autoloaded twice a
file does not really risk being included again.
- Right now we have to run includes through a proxy function [2] to
avoid granting the included file access to $this and other in-scope
variables. It's not that much overhead but can quickly lead to a
thousand extra function calls within a request's lifecycle, so just for
completeness I figured I'd mention it.
- As Mike Schinkel mentioned, the proposed API should really support
multiple maps. Composer a prepend-autoloader option which controls
whether the generated autoloader will be prepended or appended when
spl_autoload_register is called. This is required in some cases where
multiple autoloaders coexist. So the ability to add multiple maps,
including optionally prepending them would be a must IMO. The ability to
remove an autoloader and its associated classmap would also be very
welcome so one can unregister things cleanly.
So taking the above in consideration, and keeping consistency with
existing spl_* functions in mind, I would propose an API more like:
autoload_register_classmap(array $map, bool $prepend = false)
autoload_unregister_classmap(array $map)
P.S: While I am here looking at spl_* docs, it seems to me like
spl_autoload_call should be deprecated in favor of class_exists, and
spl_autoload_extensions + spl_autoload also probably should be
deprecated or at least marked as antiquated in the docs, and not
migrated to autoload_* like you suggested doing for
spl_autoload_register/unregister in another RFC.
[1]
https://github.com/composer/composer/blob/b6826f352390b4c952be8fd75d60cfd4f6f39f11/src/Composer/Autoload/ClassLoader.php
[2]
https://github.com/composer/composer/blob/b6826f352390b4c952be8fd75d60cfd4f6f39f11/src/Composer/Autoload/ClassLoader.php#L478-L481
--
Jordi Boggiano
@seldaek - https://seld.be
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