Can't set callback arg to `null` on @storybook/react 6.3.0

Describe the bug As of @storybook/react 6.3.0 can’t seem to set a callback arg to null, the argTypesRegex seems to over zealously create an actionHandler when manually setting an arg callback to null. This wasn’t happening with @storybook/react 6.2.9

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https://github.com/quangv/storybook_bug-null-callback

specifically: https://github.com/quangv/storybook_bug-null-callback/commit/4f5a1e898999158ff10221bb11dc2db525399145

export const Primary = Template.bind({});
Primary.args = {
  primary: true,
  label: 'Button',
  onClick: null // can't seem to set this to null
};

Only way I can figure out how to keep it null is tweaking the argsTypesRegex

parameters: { actions: { argTypesRegex: '^on(?!Click).*' } }

System

`ᐅ npx sb@next info

Environment Info:

System: OS: macOS 11.4 CPU: (16) x64 Intel® Core™ i9-9980HK CPU @ 2.40GHz Binaries: Node: 12.22.1 - ~/.nvm/versions/node/v12.22.1/bin/node Yarn: 2.4.2 - ~/.nvm/versions/node/v12.22.1/bin/yarn npm: 6.14.13 - ~/.nvm/versions/node/v12.22.1/bin/npm Browsers: Chrome: 91.0.4472.114 Safari: 14.1.1 npmPackages: @storybook/addon-actions: ^6.4.0-alpha.2 => 6.4.0-alpha.2 @storybook/addon-docs: ^6.4.0-alpha.2 => 6.4.0-alpha.2 @storybook/addon-essentials: ^6.4.0-alpha.2 => 6.4.0-alpha.2 @storybook/addon-links: ^6.4.0-alpha.2 => 6.4.0-alpha.2 @storybook/react: ^6.4.0-alpha.2 => 6.4.0-alpha.2`

Additional context n/a

[shilman]

Jiminy cricket!! I just released https://github.com/storybookjs/storybook/releases/tag/v6.3.1 containing PR #15394 that references this issue. Upgrade today to the @latest NPM tag to try it out!

npx sb upgrade

[brandonthomas]

@brandonthomas can you please share a reproduction? i just tried it in the original repro & it demonstrates the bug, but upgraded to 6.5 and the bug is fixed (for that example, at least)

Just did more digging and looks like we had an erroneous argTypesRegex so I think we’re good now. It was pulling in a bunch of on* render functions. Removal of argTypesRegex fixed the issue.