From a368a60eb81ea6e3264e0c8c2cb12f2ee7f0585d Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Sat, 21 May 2022 01:38:39 -0700
Subject: [PATCH 2/3] grep: assume POSIX.1-2017 for [:space:]

* src/dfasearch.c (dfawarn): Always call dfaerror now,
regardless of POSIXLY_CORRECT.
* tests/warn-char-classes: Omit test of POSIX.1-2008 behavior,
since POSIX.1-2017 allows the GNU behavior.
---
 NEWS                    | 3 +++
 doc/grep.texi           | 8 ++------
 src/dfasearch.c         | 8 ++------
 tests/warn-char-classes | 4 ----
 4 files changed, 7 insertions(+), 16 deletions(-)

diff --git a/NEWS b/NEWS
index fb0e4cf..bf2ee50 100644
--- a/NEWS
+++ b/NEWS
@@ -11,6 +11,9 @@ GNU grep NEWS                                    -*- outline -*-
   release 2.5.3 (2007), now warn that they are obsolescent and should
   be replaced by grep -E and grep -F.
 
+  Regular expressions like [:space:] are now errors even if
+  POSIXLY_CORRECT is set, since POSIX now allows the GNU behavior.
+
 ** Bug fixes
 
   In locales using UTF-8 encoding, the regular expression '.' no
diff --git a/doc/grep.texi b/doc/grep.texi
index b073fa7..71e19e0 100644
--- a/doc/grep.texi
+++ b/doc/grep.texi
@@ -1056,8 +1056,6 @@ follow file names must be treated as file names;
 by default,
 such options are permuted to the front of the operand list
 and are treated as options.
-Also, @env{POSIXLY_CORRECT} disables special handling of an
-invalid bracket expression.  @xref{invalid-bracket-expr}.
 
 @item _@var{N}_GNU_nonoption_argv_flags_
 @vindex _@var{N}_GNU_nonoption_argv_flags_ @r{environment variable}
@@ -1401,12 +1399,10 @@ Note that the brackets in these class names are
 part of the symbolic names, and must be included in addition to
 the brackets delimiting the bracket expression.
 
-@anchor{invalid-bracket-expr}
 If you mistakenly omit the outer brackets, and search for say, @samp{[:upper:]},
 GNU @command{grep} prints a diagnostic and exits with status 2, on
-the assumption that you did not intend to search for the nominally
-equivalent regular expression: @samp{[:epru]}.
-Set the @env{POSIXLY_CORRECT} environment variable to disable this feature.
+the assumption that you did not intend to search for the
+regular expression @samp{[:epru]}.
 
 Special characters lose their special meaning inside bracket expressions.
 
diff --git a/src/dfasearch.c b/src/dfasearch.c
index 744b8f8..8f48296 100644
--- a/src/dfasearch.c
+++ b/src/dfasearch.c
@@ -53,14 +53,10 @@ dfaerror (char const *mesg)
   die (EXIT_TROUBLE, 0, "%s", mesg);
 }
 
-/* For now, the sole dfawarn-eliciting condition (use of a regexp
-   like '[:lower:]') is unequivocally an error, so treat it as such,
-   when possible.  */
-void
+_Noreturn void
 dfawarn (char const *mesg)
 {
-  if (!getenv ("POSIXLY_CORRECT"))
-    dfaerror (mesg);
+  dfaerror (mesg);
 }
 
 /* If the DFA turns out to have some set of fixed strings one of
diff --git a/tests/warn-char-classes b/tests/warn-char-classes
index b1db240..0d87ce0 100755
--- a/tests/warn-char-classes
+++ b/tests/warn-char-classes
@@ -17,10 +17,6 @@ compare exp-err err || fail=1
 returns_ 1 grep '[[:space:]]' x 2> err || fail=1
 test -s err && fail=1
 
-# disabled by POSIXLY_CORRECT
-returns_ 1 env POSIXLY_CORRECT=yes grep '[:space:]' x 2> err || fail=1
-test -s err && fail=1
-
 # patterns that are considered valid
 returns_ 1 grep '[::]' x 2> err || fail=1
 test -s err && fail=1
-- 
2.34.1