Re: nano hangs when pasting five characters

Benno Schulenberg <[email protected]> Sat, 1 Mar 2025 12:44:19 +0100

Newsgroups	gmane.editors.nano.devel
Message-ID	<[email protected]>

Hello Doug,

Op 01-03-2025 om 01:47 schreef Doug Smythies:
> +               if (input == ERR) {
> +                       napms(20);  /* check for sender slower than here */
> +                       input = wgetch(frame); /* check again */
> +                               if (input == ERR)
> +                                       break;
> +               }

> But it turns out that it works fine if the sleep is 29 mSec instead of 20.
> 28 mSec and below doesn't work. 29 mSec and above works.

Interesting.  The other modification (with the 2 ms delay for each byte)
resulted in a 32 ms delay for the entire paste minus the final tilde,
which is also just enough to see the tilde.


Anyway, I have re-reported this issue on Savannah [1] and have attached
a workaround.  Are you okay with its form?

[1] https://savannah.gnu.org/bugs/?66858


Benno

0001-input-wait-a-bit-for-when-bracketed-paste-sequence-i.patch (text/x-patch, 2.3 KB)

From 1aa0830218a8c41b6bccf505538e269b0c5e56e2 Mon Sep 17 00:00:00 2001
From: Benno Schulenberg <[email protected]>
Date: Thu, 27 Feb 2025 12:01:58 +0100
Subject: [PATCH] input: wait a bit for "~" when bracketed-paste sequence
 is incomplete

When pasting something into nano over OpenSSH_for_Windows, the final
tilde of the end-of-paste sequence can lag some 29 ms behind the rest
of the sequence, causing ncurses to split it off into a next batch of
bytes.  Accommodate for this by noticing the missing tilde and then
waiting at most 200 ms for it to arrive.  This prevents the tilde
from appearing spuriously in the buffer after the paste.

This addresses https://savannah.gnu.org/bugs/?66858.
Reported-by: Doug Smythies <[email protected]>
---
 src/winio.c | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/src/winio.c b/src/winio.c
index 2fff0d9e..e002219b 100644
--- a/src/winio.c
+++ b/src/winio.c
@@ -724,10 +724,30 @@ int convert_CSI_sequence(const int *seq, size_t length, int *consumed)
 				/* Esc [ 2 n ; 2 ~ == F21...F24 on some terminals. */
 				*consumed = 5;
 #ifndef NANO_TINY
-			else if (length > 3 && seq[1] == '0' && seq[3] == '~') {
+			else {
 				/* Esc [ 2 0 0 ~ == start of a bracketed paste,
 				 * Esc [ 2 0 1 ~ == end of a bracketed paste. */
-				*consumed = 4;
+				int trailer = 0;
+
+				if (length > 3 && seq[1] == '0' && seq[3] == '~') {
+					trailer = '~';
+					*consumed = 4;
+				} else if (length == 3 && seq[1] == '0') {
+					/* Wait at most 200 ms for the missing '~' character. */
+					halfdelay(2);
+					disable_kb_interrupt();
+					trailer = getch();
+					*consumed = 3;
+					raw();
+				}
+
+				if (trailer != '~') {
+					/* Broken -- assume a truncated end-of-paste sequence. */
+					bracketed_paste = FALSE;
+					*consumed = length;
+					return ERR;
+				}
+
 				if (seq[2] == '0') {
 					bracketed_paste = TRUE;
 					return BRACKETED_PASTE_MARKER;
@@ -735,12 +755,6 @@ int convert_CSI_sequence(const int *seq, size_t length, int *consumed)
 					bracketed_paste = FALSE;
 					return BRACKETED_PASTE_MARKER;
 				}
-			} else {
-				/* When invalid, assume it's a truncated end-of-paste sequence,
-				 * in order to avoid a hang -- https://sv.gnu.org/bugs/?64996. */
-				bracketed_paste = FALSE;
-				*consumed = length;
-				return ERR;
 			}
 #endif
 			break;
-- 
2.48.1

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