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Re: [PATCH 2/2] Cygwin: pty: Disable clear screen on new pty if TERM=dumb or emacs*.

On Sep  4 15:11, Ken Brown wrote:
> On 9/4/2019 10:42 AM, Takashi Yano wrote:
> > On Wed, 4 Sep 2019 15:55:03 +0200
> > Corinna Vinschen wrote:
> >> The code in fixup_after_attach() is the only code snippet setting
> >> need_clear_screen = true.  And that code also requires term != "dump" &&
> >> term == "*emacs*" to set need_clear_screen.
> > 
> > term != "*emacs*"
> > 
> >> The code in reset_switch_to_pcon() requires that the need_clear_screen
> >> flag is true regardless of checking TERM.  So this code depends on the
> >> successful TERM check from fixup_after_attach anyway.
> >>
> >> What am I missing?
> > 
> > Two checking results may not be the same. Indeed, emacs changes
> > TERM between two checks.
> > 
> > fixup_after_attach() is called from fixup_after_exec(),
> > which is called before executing the program code.
> > reset_switch_to_pcon () is mainly called from PTY slave I/O functions.
> > This is usually from the program code.
> But the first check (the one in fixup_after_attach()) could be dropped, couldn't it?

IIUC the second test first checks for need_clear_screen but then the
TERM might have changed in the meantime which in turn requires to change
the behaviour again.  But yeah, this sound like the first patch is not
actually required at all.


Corinna Vinschen
Cygwin Maintainer

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