Re: [drew.adams@oracle.com: customizing hl-line-face should reset global-hl-line-overlay to nil]

[Richard Stallman <rms@gnu.org>]

    > Customizing `hl-line-face' has no immediate effect. You must save the
    > customization, quit Emacs, and restart Emacs, to see the effect.

    Would the attached patch help?

How about making hl-mode check occasionally whether the value
of hl-line-face has changed since the overlay was set up?
That would be cleaner because it would not depend on the user
to use the custom mechanism.  It would work with plain setq.

    However, please see my other email about using a face instead of a user
    option (variable). Wouldn't that also take care of this problem? That is, if
    there is no face variable, and users change the face itself, then that would
    be immediately reflected in the overlay, no?

Creating a special `hl-line' face for this seems like a good idea.
For compatibility, we can preserve the existing variable
`hl-line-face', and make its initial value `hl-line'.
That way, if users have customized by setting the variable,
their customizations will not break.