Hi,
Apparently there is an implementation detail in JSON_THROW_ON_ERROR
that differs in the RFC text, from the discussion on list
http://news.php.net/php.internals/100569:
> I decided to reset it to no error because there's no
> previous error that needs handling by error-checking code, the exception
> takes care of that.
RFC text:
> When passed this flag, the error behaviour of these functions is changed.
> The global error state is left untouched, and if an error occurs that would
> otherwise set it, these functions instead throw a JsonException with the
> message and code set to whatever json_last_error() and json_last_error_msg()
> would otherwise be respectively.
The implementation is highly surprising and can lead to bugs.
Imagine this code exists in a code base.
---------------------
$foo = json_decode('[bar');
// many lines of code.
// many lines of code.
// many lines of code.
$bar = json_encode('Hello world!');
if (json_last_error() !== JSON_ERROR_NONE) {
throw new Exception("encoding went wrong!");
}
echo "All is fine";
// output is "All is fine"
---------------------
And to start moving to have json_encode throw on error, they start
using the flag on the json_encode
----------------------
$foo = json_decode('[bar');
// many lines of code.
// many lines of code.
// many lines of code.
$bar = json_encode('Hello world!', JSON_THROW_ON_ERROR);
if (json_last_error() !== JSON_ERROR_NONE) {
throw new Exception("encoding went wrong!");
}
echo "All is fine";
-------------------
The result of this is that the user throw exception will be thrown
even though the encode worked correctly. https://3v4l.org/JJD5g
This is highly surprising*, and doesn't seem the right thing to be doing.
Does anyone have any objection to changing this, so that
json_last_error() + json_last_error_msg() always refer to the most
recent json_encode()/json_decode() function, as per the discussion. Or
does this need an RFC?
I've logged a bug for this regardless - https://bugs.php.net/bug.php?id=77997
cheers
Dan
Ack
* https://en.wikipedia.org/wiki/Principle_of_least_astonishment
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