bug#43470: 27.1; Drag and Drop not working properly in 27.1 on OSX

[Alan Third]

On Sat, Sep 19, 2020 at 02:45:19PM +0200, Daniel Martín wrote:
> 
> Some applications like Firefox send NSDragOperationEvery when dragging
> URLs or images. That constant means "every possible operation (copy,
> link, move)". When there's more than one operation, we want to
> consider specialized actions like ns-drag-operation-copy before
> generic ones like ns-drag-operation-generic.

Hi Daniel,

I don't think this is correct, we should always choose generic when
it's available as that is the "default" action taken by the
application. The more specialised copy, move, etc., are there for the
sending application (or user via modifiers) to force the receiving
application to do something else.

The big decision is what should Emacs do by default? My opinion is
that when receiving a URL we should insert the link as text rather
than try to open it: Emacs isn't a web browser. Perhaps that's wrong,
I'm not sure what Emacs does on other platforms.

> This change brings back the same drag and drop behavior as in Emacs
> 26.3. (Bug#43470).

This is untrue as the Emacs 26 behaviour was almost entirely arbitrary
and broken. What it does is fix this one particular use-case.
-- 
Alan Third