typeCast does not work for the execute method

[joakimbeng]

I am unable to get the typeCast option to work at all for the execute method. I have tried configuring it both on the connection level and per query, but with no success.

I have set up a minimal reproduction example here: https://github.com/joakimbeng/mysql2-bug

The reproduction repo uses mysql2 v3.12.0 and node v22.

Am I missing something or shouldn't the typeCast option work with both the query and execute methods since v3.9.0?

[sidorares]

Hi @joakimbeng - please read #1446 and linked issues, hope that will give you a context to explain current behavior and future plans

[wellwelwel]

This is occurring because the null value is not being passed through typeCast:

node-mysql2/lib/parsers/binary_parser.js

Lines 184 to 185 in 568a6cf

	parserFn(`if (nullBitmaskByte${nullByteIndex} & ${currentFieldNullBit}) `);
	parserFn(`${lvalue} = null;`);

An approach would be to check if the typeCast is a function and, if so, return the null through typeCast, for example:

parserFn(`if (nullBitmaskByte${nullByteIndex} & ${currentFieldNullBit}) {`);
if (typeof options.typeCast === 'function') {
  parserFn(`${lvalue} = options.typeCast(wrap(fields[${i}], packet), () => null);`);
} else {
  parserFn(`${lvalue} = null;`);
}
parserFn('} else {');

• Not a real fix, but it would fix this bug:
  • 

Note

typeCast is not an actively maintained feature because of its planned deprecation, but I'm open to fix it 🙋🏻‍♂️

[joakimbeng]

@wellwelwel I see!
So it's only for NULL values that it behaves differently than typeCast for the query method then?

If it's such an easy fix I'm all for it! 😃 It would be greatly appreciated if you would release that fix!

[wellwelwel]

@joakimbeng, there is a check to ensure if typeCast is a function, but it occurs after the null has already been returned:

node-mysql2/lib/parsers/binary_parser.js

Lines 195 to 199 in 568a6cf

	if (typeof options.typeCast === 'function') {
	parserFn(
	`${lvalue} = options.typeCast(${fieldWrapperVar}, function() { return ${readCode} });`,
	);
	} else {

The idea for a fix follows the same idea I mentioned, but would require a small refactoring in the order of the logic.

If it's such an easy fix I'm all for it!

Feel free to do so 🚀

• I'll merge feat(disableEval): add static parsers #3365 tomorrow (already merged), which will allow to use both the query and execute methods without eval. We can apply this fix to both sides afterwards 🙋🏻‍♂️