Re: nano hangs when pasting five characters

Benno Schulenberg <[email protected]> Thu, 27 Feb 2025 12:04:38 +0100

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

Op 26-02-2025 om 17:36 schreef Doug Smythies:
> The patch seems to work. It leaves the spurious "~" character in the pasted
> text. But rings the bell and has a clear error message.

The spurious "~" surprises me.  Are you sure you applied the patch
to a clean git checkout or cleanly unpacked tarball (apart from the
commenting of the #ifdef/#endif)?

> 7 character paste buffer:
> Sequence of hex codes: 102
> Sequence of hex codes:  1b  5b  32  30  30  7e  31  32  33  34  35  36  37  1b  5b  32  30  31  7e
> Sequence of hex codes:  18
> Sequence of hex codes:  6e
> 
> 10 character paste buffer:
> Sequence of hex codes: 102
> Sequence of hex codes:  1b  5b  32  30  30  7e  31  32  33  34  35  36  37  38  39  30
> Sequence of hex codes:  1b  5b  32  30  31  7e
> Sequence of hex codes:  18
> Sequence of hex codes:  6e

Now I'm curious what happens for an 8 and 9 character paste.
Because the above seems to suggest that OpenSSH_for_Windows
/does/ know not to break escape sequences, but that the logic
is faulty and goes wrong sometimes.

Anyway, please try the attached patch.  Make sure to apply it
to a freshly unpacked and fully unmodified 8.3 tarball.  Both
hunks should apply cleanly.  Then compile and run the new nano
and paste five characters, a dozen or so times.  There should
be no spurious tildes, no warnings, no bell.


Benno

wait-200ms.patch (text/x-patch, 1.5 KB)

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;

OpenPGP_signature.asc (application/pgp-signature, 840 B)