[PATCH v2] read: non-raw-mode fixes

[Grisha Levit]

On Wed, Jul 26, 2023 at 2:23 PM Grisha Levit <grishale...@gmail.com> wrote:
> If the last character read was an (unescaped) backslash, store it as
> such instead of as a CTLESC.  Avoids:
>
> $ printf '\\' | { read; echo "${REPLY@Q}"; }
> bash: DEBUG warning: dequote_string: string with bare CTLESC
> $'\001'

Sorry that was wrong, the CTLESC should just be removed.  Much simpler
patch below.
---
diff --git a/builtins/read.def b/builtins/read.def
index 5b2621fe..ce5bcc38 100644
--- a/builtins/read.def
+++ b/builtins/read.def
@@ -751,11 +751,11 @@ read_builtin (WORD_LIST *list)
       if (pass_next)
        {
          pass_next = 0;
-         if (c == '\n')
+         if (c == '\n' || c == '\0')
            {
              if (skip_ctlesc == 0 && i > 0)
                i--;            /* back up over the CTLESC */
-             if (interactive && input_is_tty && raw == 0)
+             if (interactive && input_is_tty && raw == 0 && c == '\n')
                print_ps2 = 1;
            }
          else
@@ -825,6 +825,11 @@ add_char:
       if (nchars > 0 && nr >= nchars)
        break;
     }
+
+  if (pass_next && skip_ctlesc == 0)
+    i--;               /* back up over the CTLESC */
+  if (skip_ctlnul && saw_escape && i == 1 && input_string[0] == CTLNUL)
+    saw_escape = 0;    /* Avoid dequoting bare CTLNUL */
   input_string[i] = '\0';
   check_read_timeout ();