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.
The `LibraryInstallerTest::testUninstall()` method mocks a `Package` object, but did not set an expectation for a call to `getName()`, while that method _is_ called in the `LibraryInstaller::uninstall()` method.
Without expectation, the mock returns `null`, which was subsequently being passed on to `strpos()` leading to the below error.
Fixes:
```
Deprecation triggered by Composer\Test\Installer\LibraryInstallerTest::testUninstall:
strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated
Stack trace:
0 [internal function]: Symfony\Bridge\PhpUnit\DeprecationErrorHandler->handleError(8192, '...', '...', 202)
1 src/Composer/Installer/LibraryInstaller.php(202): strpos(NULL, '...')
2 vendor/react/promise/src/FulfilledPromise.php(28): Composer\Installer\LibraryInstaller->Composer\Installer\{closure}(NULL)
3 src/Composer/Installer/LibraryInstaller.php(208): React\Promise\FulfilledPromise->then(Object(Closure))
4 tests/Composer/Test/Installer/LibraryInstallerTest.php(221): Composer\Installer\LibraryInstaller->uninstall(Object(Mock_InstalledRepositoryInterface_e3699f95), Object(Mock_Package_e4571076))
...
```
Not all tests in the `InstallerTest` class actually create a temporary directory and set the `$this->tempComposerHome` property.
Those tests which didn't, throw a notice in PHP 8.1.
Fixes 3 notices along the lines of:
```
Deprecation triggered by Composer\Test\InstallerTest::tearDown:
is_dir(): Passing null to parameter #1 ($filename) of type string is deprecated
Stack trace:
0 [internal function]: Symfony\Bridge\PhpUnit\DeprecationErrorHandler->handleError(8192, '...', '...', 53)
1 tests/Composer/Test/InstallerTest.php(53): is_dir(NULL)
...
```
Discovered while running the existing unit tests on PHP 8.1.
The default state of the protected `$distUrl` property is "not set" and the property may not be set when the `Package::setSourceDistReferences()` method gets called.
Fixes a total of 9 deprecation notices along the lines of:
```
Deprecation triggered by Composer\Test\DependencyResolver\PoolBuilderTest::testPoolBuilder:
preg_match(): Passing null to parameter #2 ($subject) of type string is deprecated
Stack trace:
0 [internal function]: Symfony\Bridge\PhpUnit\DeprecationErrorHandler->handleError(8192, '...', '...', 597)
1 src/Composer/Package/Package.php(597): preg_match('...', NULL)
2 src/Composer/DependencyResolver/PoolBuilder.php(360): Composer\Package\Package->setSourceDistReferences('...')
3 src/Composer/DependencyResolver/PoolBuilder.php(338): Composer\DependencyResolver\PoolBuilder->loadPackage(Object(Composer\DependencyResolver\Request), Object(Composer\Package\CompletePackage))
4 src/Composer/DependencyResolver/PoolBuilder.php(195): Composer\DependencyResolver\PoolBuilder->loadPackagesMarkedForLoading(Object(Composer\DependencyResolver\Request), Array)
5 src/Composer/Repository/RepositorySet.php(229): Composer\DependencyResolver\PoolBuilder->buildPool(Array, Object(Composer\DependencyResolver\Request))
6 tests/Composer/Test/DependencyResolver/PoolBuilderTest.php(110): Composer\Repository\RepositorySet->createPool(Object(Composer\DependencyResolver\Request), Object(Composer\IO\NullIO))
...
```
Side-note: I'm wondering why `$this->getDistUrl()` is used instead of using the `$distUrl` property. It is a property within the same class after all. Haven't changed it, but did want to raise the question.
Refs:
* https://www.php.net/manual/en/function.preg-match.php
* https://wiki.php.net/rfc/deprecate_null_to_scalar_internal_arg
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
Andreas Schempp