[ButtonBase] Improve Button accessibility

Revert #10339 removed safeguard and add additional one so anchors missing href’s are treated as buttons.

• This is not a v0.x issue.
• I have searched the issues of this repository and believe that this is not a duplicate.

Expected Behavior 🤔

An anchor with an href should not be assigned role=button.

Current Behavior 😯

An anchor with prop button w/ href is being given role of button as it misleads users. A button does not alter the url path while an href does.

Steps to Reproduce 🕹

<ListItem component={Link} to={path} button>
Hi there
</ListItem>

Context 🔦

Screen reader

[bluSCALE4]

Well then, thank you both for the feedback. I’ll try to get this in before the end of the week.

On Mon, Apr 29, 2019, 4:13 PM Olivier Tassinari [e-mail] wrote:

@bluSCALE4 https://github.com/bluSCALE4 Do you want to submit a pull request? 😃

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/mui-org/material-ui/issues/15512#issuecomment-487745771, or mute the thread https://github.com/notifications/unsubscribe-auth/AABQ526PY5JKX3CMXZZKM33PS5QGNANCNFSM4HI5Y2SQ .

[ryancogswell]

@bluSCALE4 Any role explicitly specified by the user (including null or link) will win without any additional logic. A role specified by the user will be part of ...other and ...other will win over ...buttonProps where any overlap occurs due to the order that they are spread onto the component:

        {...buttonProps}
        {...other}
      >

Here is a modification of the Third-party routing library demo showing this: https://codesandbox.io/s/xo31norvxq