Extracted from https://github.com/facebook/react/issues/12643.

We're currently diff a host node in the complete phase even if it has bailed out in the begin phase. By itself, this just means we're doing a little bit more work than necessary. But it also has some observable effects. In particular, https://github.com/facebook/react/issues/13424 (which by itself would be very rare and probably not worth fixing) is made worse because we end up committing update to inputs from another component.

I have a fix for this in https://github.com/facebook/react/pull/13423. Filing this for posterity.
</svg>
                <image {...expectSVG} />
              </svg>,
            )}
            <image {...expectSVG} />
            <foreignObject {...expectSVG}>
              <p {...expectHTML} />
              {usePortal(<p {...expectHTML} />)}
              <p {...expectHTML} />
            </foreignObject>
          </svg>
          <image {...expectSVG} />
        </svg>
        <p {...expectHTML} />
      </div>,
    );
    assertNamespacesMatch(
      <div {...expectHTML}>
        <svg {...expectSVG}>
          <foreignObject {...expectSVG}>
            <p {...expectHTML} />
            {usePortal(
              <svg {...expectSVG}>
                <image {...expectSVG} />
                <svg {...expectSVG}>
                  <image {...expectSVG} />
                  <foreignObject {...expectSVG}>
                    <p {...expectHTML} />
                  </foreignObject>
                  {usePortal(<p {...expectHTML} />)}