bug#24914: 24.5; isearch-regexp: wrong error message

[Noam Postavsky]

Drew Adams <drew.adams@oracle.com> writes:

> 3. C-M-s \(.\|^J\)\{,40000\}
>
> That shows the error message: [incomplete input], which is wrong, IMO.

The reason it doesn't work is because the number of repitions is limited
to 32767 (#x7fff).  Obviously that should be documented in the manual.

As to the error message itself, there isn't really a way to distinguish
between incomplete and invalid input, so the only thing I can see to do
is to change the message to [incomplete or invalid input].

>From f7bb728281408170cfe79005b03d2b382a84cdbd Mon Sep 17 00:00:00 2001
From: Noam Postavsky <npostavs@gmail.com>
Date: Sat, 2 Dec 2017 19:01:54 -0500
Subject: [PATCH] Document limitation of regexp repetition (Bug#24914)

* doc/lispref/searching.texi (Regexp Backslash): Explain that \{m,n\}
may only use numbers up to 32767.
* lisp/isearch.el (isearch-search): Update error message to include
invalid input possibility.
---
 doc/lispref/searching.texi | 3 ++-
 lisp/isearch.el            | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/doc/lispref/searching.texi b/doc/lispref/searching.texi
index 755fa554bb..92b7e6d17e 100644
--- a/doc/lispref/searching.texi
+++ b/doc/lispref/searching.texi
@@ -639,7 +639,8 @@ Regexp Backslash
 is a more general postfix operator that specifies repetition with a
 minimum of @var{m} repeats and a maximum of @var{n} repeats.  If @var{m}
 is omitted, the minimum is 0; if @var{n} is omitted, there is no
-maximum.
+maximum.  For both forms, @var{m} and @var{n}, if specified, may be no
+larger than 32767.
 
 For example, @samp{c[ad]\@{1,2\@}r} matches the strings @samp{car},
 @samp{cdr}, @samp{caar}, @samp{cadr}, @samp{cdar}, and @samp{cddr}, and
diff --git a/lisp/isearch.el b/lisp/isearch.el
index 13fa97ea71..dfc5f9f3f7 100644
--- a/lisp/isearch.el
+++ b/lisp/isearch.el
@@ -2853,7 +2853,7 @@ isearch-search
       ((string-match
        "\\`Premature \\|\\`Unmatched \\|\\`Invalid "
        isearch-error)
-       (setq isearch-error "incomplete input"))
+       (setq isearch-error "incomplete or invalid input"))
       ((and (not isearch-regexp)
            (string-match "\\`Regular expression too big" isearch-error))
        (cond
-- 
2.11.0