From: Takashi Yano <takashi.yano@nifty.ne.jp>
To: cygwin-patches@cygwin.com
Subject: Re: [PATCH v2] Cygwin: pty: Reduce unecessary input transfer.
Date: Fri, 10 Dec 2021 19:20:40 +0900 [thread overview]
Message-ID: <20211210192040.71f88b263b8c20f2f61db310@nifty.ne.jp> (raw)
In-Reply-To: <nycvar.QRO.7.76.6.2112092345060.90@tvgsbejvaqbjf.bet>
On Fri, 10 Dec 2021 00:05:27 +0100 (CET)
Johannes Schindelin wrote:
> sorry for responding to a patch you sent almost 10 months ago... but... I
> am struggling with it.
>
> First of all, let me describe the problem I am seeing (see also
> https://github.com/git-for-windows/git/issues/3579): after upgrading the
> MSYS2 runtime to v3.3.3 in Git for Windows, whenever I ask `git.exe` to
> spawn `vim.exe` to edit any file, after quitting `vim` I see spurious ANSI
> sequences being "ghost-typed" into the terminal (which is a MinTTY running
> under `TERM=xterm`).
>
> Apparently the ANSI sequences report the cursor position and the
> foreground/background color in response to a CSI [ 6n sent from `vim`.
>
> Clearly, those sequences should go to `vim.exe`, but they mostly don't
> arrive there (but in MinTTY instead, as if I had typed them). Sometimes,
> the foreground/background color seems to arrive in the `vim` process, but
> the cursor position almost always does not. I suspect that it is important
> that `git.exe` is a non-MSYS2 process whereas `vim.exe` is an MSYS2
> process, and something inside the MSYS2 runtime is at fault.
>
> I've bisected this incorrect behavior to the patch I am replying to.
>
> I tried to trigger the same bug in pure Cygwin (as opposed to MSYS2),
> specifically using `disable_pcon` (because MSYS2 defaults to not using the
> pseudo console support because I ran into too many issues to be confident
> enough in it yet), but I think that Cygwin's `vim` is too old and
> therefore might not even send that CSI [ 6n (although `:h t_RV` _does_
> show the expected help).
>
> Now, the patch which I am responding to is completely obscure to me. It is
> very, very unclear to me whether it really tries to only do one thing
> (namely to transfer the input no longer in `read()` but in `setpgid()`),
> or rather does many things at once. Even worse, I have not the faintest
> clue how this patch is trying to accomplish what the commit message
> describes (_because_ it does so many things at once), nor how that could
> be related to the observed incorrect behavior, and as a consequence I have
> no idea how I can hope to fix said observed incorrect behavior.
>
> Could you help shed some light into the problem?
Thanks for the report.
Could you please test if the following patch solves the issue?
diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc
index f523dafed..ba282b897 100644
--- a/winsup/cygwin/fhandler_tty.cc
+++ b/winsup/cygwin/fhandler_tty.cc
@@ -1239,10 +1239,13 @@ fhandler_pty_slave::mask_switch_to_pcon_in (bool mask, bool xfer)
else if (InterlockedDecrement (&num_reader) == 0)
CloseHandle (slave_reading);
+ bool need_xfer =
+ get_ttyp ()->switch_to_pcon_in && !get_ttyp ()->pcon_activated;
+
/* In GDB, transfer input based on setpgid() does not work because
GDB may not set terminal process group properly. Therefore,
transfer input here if isHybrid is set. */
- if (isHybrid && !!masked != mask && xfer
+ if ((isHybrid || need_xfer) && !!masked != mask && xfer
&& GetStdHandle (STD_INPUT_HANDLE) == get_handle ())
{
if (mask && get_ttyp ()->pcon_input_state_eq (tty::to_nat))
@@ -1536,7 +1539,7 @@ out:
if (ptr0)
{ /* Not tcflush() */
bool saw_eol = totalread > 0 && strchr ("\r\n", ptr0[totalread -1]);
- mask_switch_to_pcon_in (false, saw_eol);
+ mask_switch_to_pcon_in (false, saw_eol || len == 0);
}
}
@@ -2214,6 +2217,15 @@ fhandler_pty_master::write (const void *ptr, size_t len)
return len;
}
+ if (to_be_read_from_pcon () && !get_ttyp ()->pcon_activated
+ && get_ttyp ()->pcon_input_state == tty::to_cyg)
+ {
+ WaitForSingleObject (input_mutex, INFINITE);
+ fhandler_pty_slave::transfer_input (tty::to_nat, from_master,
+ get_ttyp (), input_available_event);
+ ReleaseMutex (input_mutex);
+ }
+
line_edit_status status = line_edit (p, len, ti, &ret);
if (status > line_edit_signalled && status != line_edit_pipe_full)
ret = -1;
--
Takashi Yano <takashi.yano@nifty.ne.jp>
next prev parent reply other threads:[~2021-12-10 10:21 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-11 9:09 Takashi Yano
2021-02-12 9:43 ` Corinna Vinschen
2021-12-09 23:05 ` Johannes Schindelin
2021-12-10 10:20 ` Takashi Yano [this message]
2021-12-10 11:12 ` Johannes Schindelin
2021-12-11 13:40 ` Takashi Yano
2021-12-13 9:09 ` Takashi Yano
2021-12-13 12:33 ` Takashi Yano
2021-12-14 11:02 ` Takashi Yano
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20211210192040.71f88b263b8c20f2f61db310@nifty.ne.jp \
--to=takashi.yano@nifty.ne.jp \
--cc=cygwin-patches@cygwin.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).