Empty json dump due to encode_json silently failing

Author: simkocCreated Jan 23, 2025Updated Jan 23, 2025

When trying to work with encoded strings in a php file I am having trouble getting json to work:

proofOcConcept.php

<?php
echo gzuncompress("KL");
echo "\x1f\x8b\x08\x00\x00\x00\x00\x00";

Dumping Json:

PHP-Parser $> ./bin/php-parse -j proofOfConcept.php
====> File ./proofOcConcept.php:
==> JSON dump:

Dumping Nodes:

PHP-Parser $> ./bin/php-parse -d proofOfConceptPhp.php 
====> File proofOfConceptPhp.php:
==> Node dump:
array(
    0: Stmt_Echo(
        exprs: array(
            0: Expr_FuncCall(
                name: Name(
                    name: gzuncompress
                )
                args: array(
                    0: Arg(
                        name: null
                        value: Scalar_String(
                            value: KL
                        )
                        byRef: false
                        unpack: false
                    )
                )
            )
        )
    )
    1: Stmt_Echo(
        exprs: array(
            0: Scalar_String(
                value: �
            )
        )
    )
)

Diving deeper into the issue and adding the the JSON_THROW_ON_ERROR flag in line 85 of bin/php-parse results in:

PHP-Parser $> ./bin/php-parse -j proofOfConcept.php
====> File ./proofOcConcept.php:
==> JSON dump:
PHP Fatal error:  Uncaught JsonException: Malformed UTF-8 characters, possibly incorrectly encoded in /home/simon/tmp/PHP-Parser/bin/php-parse:85
Stack Trace:
#0 /home/simon/tmp/PHP-Parser/bin/php-parse(85): json_encode()
#1 {main}
  thrown in /home/simon/tmp/PHP-Parser/bin/php-parse on line 85

also at the same line adding the JSON_INVALID_UTF8_IGNORE seems to fix the issue and produce the expected output:

PHP-Parser $> ./bin/php-parse -j proofOfConcept.php
====> File ./proofOcConcept.php:
==> JSON dump:
[
   {
        ... very long json file ....
   }
]

I am using an up-to-date arch Linux which currently has PHP 8.3.15.

I would propose to either only add the JSON_TRHOW_ON_ERROR flag to prevent silently failing or to also add JSON_INVALID_UTF8_IGNORE flag. I have made a PR for the latter proposal, as this fixes my immediate issue.

Source: nikic/PHP-Parser

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