Subject: readline event-hook may hang while waiting on input
Package: libreadline8t64
Source: readline
X-Debbugs-Cc: john.chittum@canonical.com
Version: 8.3-1
Severity: important
Tags: patch

readline 8.3 contains a bug, identified upstream, with the event-hook
leading to complete hang waiting for input.

https://lists.gnu.org/archive/html/bug-readline/2025-07/msg00012.html

upstream patch at :

https://ftp.gnu.org/gnu/readline/readline-8.3-patches/readline83-001

This affects packages such as octave. Reproducible:

* apt install octave
* octave --no-gui
* attempt input.

Tracked in Ubuntu at :
https://bugs.launchpad.net/ubuntu/+source/readline/+bug/2118818

attached is a unified diff version with *somewhat* close to dep3 headers (i
make no promises)

--- a/input.c
+++ b/input.c
@@ -261,13 +261,16 @@
   input = 0;
   tty = fileno (rl_instream);
·
-  /* Move this up here to give it first shot, but it can't set chars_avail
*/
+  /* Move this up here to give it first shot, but it can't set chars_avail,
+     so we assume a single character is available. */
   /* XXX - need rl_chars_available_hook? */
   if (rl_input_available_hook)
     {
       result = (*rl_input_available_hook) ();
       if (result == 0)
         result = -1;
+      else
+        chars_avail = 1;
     }
·
 #if defined (HAVE_PSELECT) || defined (HAVE_SELECT)
@@ -285,6 +288,7 @@
 #endif
       if (result <= 0)
 »······return 0;»······/* Nothing to read. */
+      result = -1;»····/* there is something, so check how many chars
below */
     }
 #endif
·
--- a/patchlevel
+++ b/patchlevel
@@ -1,3 +1,3 @@
 # Do not edit -- exists only for use by patch
·
-0
+1

We believe that the bug you reported is fixed in the latest version of
readline, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1111639@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Matthias Klose <doko@debian.org> (supplier of updated readline package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Thu, 28 Aug 2025 15:09:37 +0200
Source: readline
Architecture: source
Version: 8.3-2
Distribution: unstable
Urgency: medium
Maintainer: Matthias Klose <doko@debian.org>
Changed-By: Matthias Klose <doko@debian.org>
Closes: 1097778 1111639
Changes:
 readline (8.3-2) unstable; urgency=medium
 .
   * Apply upstream patches 001. Closes: #1111639.
   * Builds with GCC 15. Closes: #1097778.
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