File "UseStatementPass.php"
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<?php
/*
* This file is part of Psy Shell.
*
* (c) 2012-2025 Justin Hileman
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Psy\CodeCleaner;
use PhpParser\Node;
use PhpParser\Node\Identifier;
use PhpParser\Node\Name; // @phan-suppress-current-line PhanUnreferencedUseNormal - used for type checks
use PhpParser\Node\Stmt\Namespace_;
use PhpParser\Node\Stmt\Use_;
use PhpParser\Node\Stmt\UseItem;
use PhpParser\Node\Stmt\UseUse;
use Psy\Exception\FatalErrorException;
/**
* Provide implicit use statements for subsequent execution.
*
* The use statement pass remembers the last use statement line encountered:
*
* use Foo\Bar as Baz;
*
* ... which it then applies implicitly to all future evaluated code, until the
* current namespace is replaced by another namespace.
*
* Extends NamespaceAwarePass to leverage shared alias tracking.
*/
class UseStatementPass extends NamespaceAwarePass
{
/**
* {@inheritdoc}
*/
public function enterNode(Node $node)
{
// Check for use statement conflicts BEFORE parent adds it to aliases
// Skip re-injected use statements (marked with 'psyshReinjected' attribute)
if ($node instanceof Use_ && !$node->getAttribute('psyshReinjected')) {
$this->validateUseStatement($node);
}
return parent::enterNode($node);
}
/**
* Re-inject use statements from previous inputs.
*
* Each REPL input is evaluated separately; re-injecting use statements matches PHP behavior for
* namespaces and use statements in a file.
*
* @return Node[]|null Array of nodes
*/
public function beforeTraverse(array $nodes)
{
parent::beforeTraverse($nodes);
if (!$this->cleaner) {
return null;
}
// Check for namespace declarations in the input
foreach ($nodes as $node) {
if ($node instanceof Namespace_) {
// Only re-inject use statements if this is a wrapper created by NamespacePass.
// This matches PHP behavior: explicit namespace declaration clears use statements.
if ($node->getAttribute('psyshReinjected')) {
$aliases = $this->cleaner->getAliasesForNamespace($node->name);
if (!empty($aliases)) {
$useStatements = $this->createUseStatements($aliases);
$node->stmts = \array_merge($useStatements, $node->stmts ?? []);
}
}
// Don't process other nodes or return modified nodes
return null;
}
}
// No namespace declaration in input, or re-applied by NamespacePass; re-inject use
// statements for the empty namespace.
$aliases = $this->cleaner->getAliasesForNamespace(null);
if (!empty($aliases)) {
$useStatements = $this->createUseStatements($aliases);
$nodes = \array_merge($useStatements, $nodes);
}
return $nodes;
}
/**
* If we have aliases but didn't leave a namespace (global namespace case), persist them to
* CodeCleaner for the next traversal.
*
* {@inheritdoc}
*/
public function afterTraverse(array $nodes)
{
if (!$this->cleaner) {
return null;
}
// Persist aliases if they're at the global level (not inside any namespace)
if (!empty($this->aliases)) {
$this->cleaner->setAliasesForNamespace(null, $this->aliases);
}
return null;
}
/**
* Validate that a use statement doesn't conflict with existing aliases.
*
* @throws FatalErrorException if the alias is already in use
*
* @param Use_ $stmt The use statement node
*/
private function validateUseStatement(Use_ $stmt): void
{
foreach ($stmt->uses as $useItem) {
$alias = \strtolower($useItem->getAlias());
if (isset($this->aliases[$alias])) {
throw new FatalErrorException(\sprintf('Cannot use %s as %s because the name is already in use', $useItem->name->toString(), $useItem->getAlias()), 0, \E_ERROR, null, $stmt->getStartLine());
}
}
}
/**
* Create use statement nodes from stored aliases.
*
* @param array $aliases Map of lowercase alias names to Name nodes
*
* @return Use_[] Array of use statement nodes
*/
private function createUseStatements(array $aliases): array
{
$useStatements = [];
foreach ($aliases as $alias => $name) {
// Create UseItem (PHP-Parser 5.x) or UseUse (PHP-Parser 4.x)
$useItem = \class_exists(UseItem::class)
? new UseItem($name, new Identifier($alias))
: new UseUse($name, $alias);
// Mark as re-injected so we don't validate it
$useStatements[] = new Use_([$useItem], Use_::TYPE_NORMAL, ['psyshReinjected' => true]);
}
return $useStatements;
}
}