Introduces a `PlatformRequirementFilter` with methods that help to decide if a requirement is ignored or not as discussed in #10045 but without changing behaviour.
I've looked into 10067 and have come to the conclusion that using a single regex to strip the heredoc/nowdocs is always going to run into trouble as:
* Either the matching will be too greedy (issue 10067);
* Or the matching will run into backtrace limits for large heredoc/nowdocs.
We cannot solve both within a single regex.
So, I'm proposing a slightly different solution which should support both and should also improve performance for files containing large heredoc/nowdocs.
The `stripHereNowDocs()` function will find a start marker and remember the offset of the start marker.
It will then find the end marker and strip the contents between the two (replace with `null`).
The function will then recurse onto itself until all heredocs/nowdocs in a file have been removed.
By using a look ahead assertion to match "new line - maybe whitespace - marker", the negative performance impact of the `.*` is significantly mitigated and backtracing will be severely limited.
This fixes the bug as reported in 10037.
The bug was discovered due to a PHP 8.1 "passing null to non-nullable" deprecation notice being thrown, but is not a PHP 8.1 bug.
In actual fact, this issue affected all PHP versions and could lead to incomplete classmaps when the code base contained files with huge heredocs/nowdocs.
The regex change (not completely) incidentally also fixes an issue with markers in a heredoc/nowdoc not being correctly handled. This bug could lead to "classes" being added to the class map which aren't actually classes.
Fixes 10037
As Composer is generally compatible with newer versions of Symfony than the bundled ones, this should
not be a problem if dependencies are shared, and it ensures that the most relevant code gets loaded.
PHP 8.1 supports Enums, and [Enums follow class-semantics](https://php.watch/versions/8.1/enums#class-semantics-autoload).
Composer's class-map generator currently looks for `class`, `interface`, and `trait` keywords. If Composer is run in PHP 8.1 or later, Composer now additionally looks for `enum` keyword as well. This is similar to how Hack's `enum` support is added.
This PR also adds tests for basic enums, backed enums, namespaced enums, and an enum that implements an interface and extends a class.
A recent change in the ClassAutoloader (#9635) added support for specifying a vendorDir, and `\Composer\Autoload\ClassLoader::register` now has a if-elseif-else chain.
The first block has a `// no-op` comment, followed by an `elseif` block. It's more readable to `return;`, and remove the `elseif` for readability.
Jordi Boggiano
Wataru Kurashima
Helmut Hummel
Nicolas Grekas
Martin Herndl
immeëmosol
jrfnl
Ayesh Karunaratne
Jakub Bouček
zorn