private function handleAssign(NodeTraversal $t, \PHPParser_Node_Expr_Assign $node)
{
if (!$node->var instanceof \PHPParser_Node_Expr_Variable || !is_string($node->var->name)) {
return;
}
$scope = $t->getScope();
if (null === ($var = $scope->getVar($node->var->name))) {
return;
}
if ($var->isReference()) {
return;
}
$nameNode = $var->getNameNode();
if ($nameNode instanceof \PHPParser_Node_Param && $this->getSetting('overriding_parameter')) {
$this->phpFile->addComment($node->getLine(), Comment::warning('suspicious_code.assignment_to_parameter', 'Consider using a different name than the parameter ``$%param_name%``. This often makes code more readable.', array('param_name' => $node->var->name)));
} else {
if ($nameNode instanceof \PHPParser_Node_Expr_ClosureUse && $this->getSetting('overriding_closure_use')) {
$this->phpFile->addComment($node->getLine(), Comment::warning('suspicious_code.assignment_to_closure_import', 'Consider using a different name than the imported variable ``$%variable_name%``, or did you forget to import by reference?', array('variable_name' => $node->var->name)));
}
}
}
private function tryRemoveAssignment(NodeTraversal $t, \PHPParser_Node $n, \PHPParser_Node $exprRoot = null, $inState, $outState)
{
$parent = $n->getAttribute('parent');
if (NodeUtil::isAssignmentOp($n)) {
$lhs = $n->var;
$rhs = $n->expr;
if ($n instanceof \PHPParser_Node_Expr_AssignList) {
$i = 0;
foreach ($n->vars as $var) {
if (null === $var) {
$i += 1;
continue;
}
$newNode = new \PHPParser_Node_Expr_Assign($var, new \PHPParser_Node_Expr_ArrayDimFetch($rhs, new \PHPParser_Node_Scalar_LNumber($i)), $n->getLine());
$newNode->setAttribute('is_list_assign', true);
$this->tryRemoveAssignment($t, $newNode, $exprRoot, $inState, $outState);
$i += 1;
}
return;
}
// Recurse first. Example: dead_x = dead_y = 1; We try to clean up dead_y first.
if (null !== $rhs) {
$this->tryRemoveAssignment($t, $rhs, $exprRoot, $inState, $outState);
$rhs = $lhs->getAttribute('next');
}
$scope = $t->getScope();
if (!$lhs instanceof \PHPParser_Node_Expr_Variable || !is_string($lhs->name)) {
return;
}
if (!$scope->isDeclared($lhs->name)) {
return;
}
if (in_array($lhs->name, NodeUtil::$superGlobalNames, true)) {
return;
}
$var = $scope->getVar($lhs->name);
$escaped = $this->liveness->getEscapedLocals();
if (isset($escaped[$var])) {
return;
// Local variable that might be escaped due to closures.
}
// If we have an identity assignment such as a=a, always remove it
// regardless of what the liveness results because it does not
// change the result afterward.
if (null !== $rhs && $rhs instanceof \PHPParser_Node_Expr_Variable && $var->getName() === $rhs->name && $n instanceof \PHPParser_Node_Expr_Assign) {
$this->phpFile->addComment($n->getLine(), Comment::warning('dead_assignment.assignment_to_itself', 'Why assign ``%variable%`` to itself?', array('variable' => '$' . $rhs->name)));
return;
}
// At the moment we miss some dead assignments if a variable is killed,
// and defined in the same node of the control flow graph.
// Example: $a = 'foo'; return $a = 'bar';
if ($outState->isLive($var)) {
return;
// Variable is not dead.
}
// Assignments to references do not need to be used in the
// current scope.
if ($var->isReference()) {
return;
}
// if ($inState->isLive($var)
// /*&& $this->isVariableStillLiveWithinExpression($n, $exprRoot, $var->getName()) */) {
// The variable is killed here but it is also live before it.
// This is possible if we have say:
// if ($X = $a && $a = $C) {..} ; .......; $a = $S;
// In this case we are safe to remove "$a = $C" because it is dead.
// However if we have:
// if ($a = $C && $X = $a) {..} ; .......; $a = $S;
// removing "a = C" is NOT correct, although the live set at the node
// is exactly the same.
// TODO: We need more fine grain CFA or we need to keep track
// of GEN sets when we recurse here. Maybe add the comment anyway, and let the user decide?
// return;
// }
if ($n instanceof \PHPParser_Node_Expr_Assign) {
if ($n->getAttribute('is_list_assign', false)) {
$this->phpFile->addComment($n->getLine(), Comment::warning('dead_assignment.unnecessary_list_assign', 'The assignment to ``$%variable%`` is dead. Consider omitting it like so ``list($first,,$third)``.', array('variable' => $var->getName())));
return;
}
$this->phpFile->addComment($n->getLine(), Comment::warning('dead_assignment.unnecessary_var_assign', 'The assignment to ``$%variable%`` is dead and can be removed.', array('variable' => $var->getName())));
return;
}
}
}
