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
... to proof the existence of the bug and demonstrate the effect.
Note: in the test the backtrack limit is being lowered (and restored back to the default afterwards) to prevent the tests needing ridiculously huge test fixture files.
Jordi Boggiano