Uncaught Error: Invalid path b:firstLog

[sillvva]

Describe the bug

This code here is throwing an error for a boolean checkbox which is being provided the name b:firstLog.

kit/packages/kit/src/runtime/form-utils.svelte.js

Lines 68 to 79 in 1ef73e8

	const path_regex = /^[a-zA-Z_$]\w*(\.[a-zA-Z_$]\w*|\[\d+\])*$/;
	/**
	* @param {string} path
	*/
	export function split_path(path) {
	if (!path_regex.test(path)) {
	throw new Error(`Invalid path ${path}`);
	}
	return path.split(/\.|\[|\]/).filter(Boolean);
	}

Error

The error occurs when the checkbox is toggled.

Uncaught Error: Invalid path b:firstLog
    at split_path (form-utils.svelte.js?v=07427efc:66:9)
    at HTMLFormElement.<anonymous> (form.svelte.js?v=07427efc:415:19)

Reproduction

See the browser console and try toggling the checkbox.
https://stackblitz.com/edit/sveltejs-kit-template-default-zfggavbm?file=package.json,src%2Froutes%2Ftest.remote.js,src%2Froutes%2F%2Bpage.svelte

System Info

  System:
    OS: macOS 26.0.1
    CPU: (16) arm64 Apple M4 Max
    Memory: 1.36 GB / 48.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.12.0 - /Users/sillvva/.nvm/versions/node/v22.12.0/bin/node
    npm: 10.9.0 - /Users/sillvva/.nvm/versions/node/v22.12.0/bin/npm
    pnpm: 10.11.0 - /Users/sillvva/.nvm/versions/node/v22.12.0/bin/pnpm
    bun: 1.2.20 - /Users/sillvva/.bun/bin/bun
  Browsers:
    Firefox: 140.0.2
    Safari: 26.0.1
  npmPackages:
    @sveltejs/adapter-node: ^5.3.3 => 5.3.3 
    @sveltejs/kit: ^2.46.1 => 2.46.1 
    @sveltejs/vite-plugin-svelte: ^6.2.1 => 6.2.1 
    svelte: ^5.39.9 => 5.39.9 
    vite: ^7.1.9 => 7.1.9 

Severity

blocker

Additional Information

No response

[sillvva]

Added a MRE:

https://stackblitz.com/edit/sveltejs-kit-template-default-zfggavbm?file=package.json,src%2Froutes%2Ftest.remote.js,src%2Froutes%2F%2Bpage.svelte,src%2Froutes%2F%2Blayout.svelte

[sillvva]

This is the line that is calling the split_path method without parsing out the b: and n:

kit/packages/kit/src/runtime/client/remote-functions/form.svelte.js

Line 413 in 1ef73e8

const path = split_path(name);

[sillvva]

Here's the fix

kit/packages/kit/src/runtime/client/remote-functions/form.svelte.js

Lines 402 to 408 in 1ef73e8

	} else {
	input = set_nested_value(
	input,
	name,
	element.type === 'checkbox' && !element.checked ? null : element.value
	);
	}

To:

} else {
	let value = element.type === 'checkbox' && !element.checked ? null : element.value;
	if (name.startsWith('n:')) {
		name = name.slice(2);
		value = value === '' ? undefined : parseFloat(value);
	} else if (name.startsWith('b:')) {
		name = name.slice(2);
		value = value === 'on';
	}

	input = set_nested_value(input, name, value);
}

I'm not sure if that would break anything else, but it resolves this error.

[teemingc]

closed by #14649