Comments in multi-line string concatenation statement gets removed

[naveen17797]

For example

$test = 'apple' .
       // this comment wont be retained
       'orange';

After processing, this comment gets removed when AST is converted to code with new PrettyPrinter\Standard

$test = 'apple' . 'orange';

[nikic]

The comment is part of the AST:

array(
    0: Stmt_Expression(
        expr: Expr_Assign(
            var: Expr_Variable(
                name: test
            )
            expr: Expr_BinaryOp_Concat(
                left: Scalar_String(
                    value: apple
                )
                right: Scalar_String(
                    value: orange
                    comments: array(
                        0: // this comment wont be retained
                    )
                )
            )
        )
    )
)

But the pretty printer will only print comments that are at the statement (or some other kind of list) level, but not those nested inside expressions in odd ways.

Using the formatting-preserving printer (https://github.com/nikic/PHP-Parser/blob/master/doc/component/Pretty_printing.markdown#formatting-preserving-pretty-printing) should retain this comment though.

[naveen17797]

@nikic i tried this, but it doesn't seem to work.

Example snippet

<?php
		$code = file_get_contents(__DIR__ . '/test.php');
		$parser = (new ParserFactory())->createForVersion(PhpVersion::fromString('7.4'));
		$old_ast = $parser->parse($code);
		$old_tokens = $parser->getTokens();
		$traverser = new NodeTraverser();
		$new_ast = $traverser->traverse($old_ast);
		$pretty_printer =  new PhpParser\PrettyPrinter\Standard();
		var_dump($pretty_printer->printFormatPreserving($new_ast, $old_ast, $old_tokens));

file.php contents

<?php
$test = 'apple' .
       // this comment wont be retained
       'orange';

Output:

<?php
$example = 'apple' . 'orange';"

Version: 5.4.0

[nikic]

I think the problem with that code snippet is that CloningVisitor is not added to the NodeTraverser.