Subject: bug#30186: 27.0.50; Password is not hidden in read-passwd

From: Alan Mackenzie <[email-masked]>
Date: Sat, 27 Jan 2018 09:21:24 +0000

Hello, Martin.

On Sat, Jan 27, 2018 at 09:27:46 +0100, martin rudalics wrote:
>  > The problem here appears to be a fundamental design bug in Emacs:
>  > that text properties are regarded as part of the buffer rather than
>  > something accompanying the buffer, as overlays are.

> Is that interpretation correct?

No.  I'm half joking.  But an awful lot of Lisp code runs an awful lot of
code separating text properties from actual text, mainly by preventing
the change hooks being run for text property changes.

read-passwd is an example (the only one I know) of the change hooks being
an essential part of text property manipulation.

> I always regard text properties part of some text (as they are retained
> when copying text from one buffer to another) and only their text part
> of the buffer.  And I do regard overlays parts of their buffers.  Am I
> wrong?

Text properties are indeed part of the buffer (or string).  But I don't
think overlays are - if you have an overlay on part of a buffer, and copy
that part into a string, I don't think the overlay stays on the copy.

> martin

-- 
Alan Mackenzie (Nuremberg, Germany).