bug#34969: 26.2; `emacs -Q` unable to copy \200's eight-bit detail buffer

[Van L <van@scratch.space>]

> On 26 Mar 2019, at 04:46, Eli Zaretskii <eliz@gnu.org> wrote:
> 
>> From: Van L <van@scratch.space>
>> Date: Mon, 25 Mar 2019 14:14:47 +1100
>> Cc: 34969@debbugs.gnu.org
>> 
>>>> : 7 `emacs -Q`
>>>> : [this is the first time for `emacs -Q]
>>>> : [has problem the forth time run for thise version]
>>>> : [on XQuartz]
>>>> : [~/bin/emacs26.2r1 links to \200nfs\200/build/emacs26.2-rc1/bin/emacs-26.2]
>>>> : GNU Emacs 26.2 (build 1, x86_64-apple-darwin15.6.0, X toolkit)
>>>> : of 2019-03-21
>>> 
>>> Does "the forth time" mean do all the steps 4 times before the problem
>>> happens?  Or does it mean repeat only some of the steps 4 times?
>> 
>> 4th time means the forth time starting from the initial condition before Emacs is started for the same Emacs version to run in isolation without other instances running.
> 
> So you actually started Emacs 4 times, and only on the 4th restart it
> exhibited the problem?

Of the 7 times listed in the bug-report, I started four times 26.2, three of those operated the .emacs file.

1. did *not* show the problem
2. did show the problem
3. did
4. did; when called as `emacs -Q` 

>  If so, I'm quite sure this is caused by some
> external software, perhaps something that takes ownership of the
> clipboard contents, e.g. because it wants to let you have several
> different clipboard buffers.  Do you have something like that
> installed and active?

Provided there are no nasty contaminations from the 'net, I have the plain old platformOS, MacPort, XQuartz installed.
Copy and paste within the one Emacs is being interfered with if what you suggest is true.

> 
>>> IOW, can you please show the transcript of repeated steps in these
>>> situations?
>> 
>> That is under the section `-- A` in the bug-report. 
>> I had hoped the trace was caught in the bug-report.
> 
> Section A just gives a single sequence, but it doesn't tell how to do
> that several times, i.e. what exactly is repeated N times.

a. run Emacs
b. goto *scratch* buffer
c. create new frame
d. lookup keybindings for *scratch* buffer
e. find `self`
f. for the two variants of \200 copy and paste details buffer to *scratch*

Repeat the above a-f steps 7 times as listed in the bug-report for those platforms detailed.

> 
> 
>>> What happens if you set interprogram-cut-function and
>>> interprogram-paste-function to nil?
>> 
>> Will do the next time I get a chance.
> 
> If I'm right, the problem will disappear.

I am inside the one Emacs's copy and paste, and not going out of the Emacs.

>>> (And why do your symlink targets include \200 characters?)
>> 
>> I used `C-x 8 RET horizontal ellipsis` the email program was unable to process.
>> The \200 was what the email program used as substitute.
> 
> Strange email program: \200 is an unassigned codepoint.

That was the emacs-bug-report mechanism in Emacs that did that.