Undeprecate some uses of unescaped { in patterns

perl5 really went ahead with fatalizing too many occurences
of unescaped {} with every prefix, cperl fatalizes only the
actually reserved character prefixes: \NpPbBxog. [cperl #362]

Remove the old (and unused) deprecation messages.

See commit 76416d1 - Karl Williamson

Author: rurban

.git-rr-cache

@@ -6826,11 +6826,9 @@ C<undef *foo>.
 (A) You've accidentally run your script through B<csh> instead of Perl.
 Check the #! line, or manually feed your script into Perl yourself.
 
-=item Unescaped left brace in regex is deprecated here (and will be fatal in Perl 5.30), passed through in regex; marked by S<<-- HERE> in m/%s/
+=item Unescaped left brace in regex is passed through in regex; marked by S<<-- HERE> in m/%s/
 
-=item Unescaped left brace in regex is deprecated here (and will be fatal in Perl 5.32), passed through in regex; marked by S<<-- HERE> in m/%s/
-
-(D deprecated, regexp)  The simple rule to remember, if you want to
+(W regexp)  The simple rule to remember, if you want to
 match a literal C<"{"> character (U+007B C<LEFT CURLY BRACKET>) in a
 regular expression pattern, is to escape each literal instance of it in
 some way.  Generally easiest is to precede it with a backslash, like
@@ -6883,7 +6881,7 @@ as the first character following a quantifier
 
 =item *
 
-in cperl only if the unicode group is one of the following reserved:
+in cperl only if the unicode group is one of the following reserved prefixes:
 
  Name:     /\N{/
  Property: /\p{/ /\P{/

pod/perldiag.pod

@@ -820,6 +820,7 @@ static const scan_data_t zero_scan_data = {
 	                                    REPORT_LOCATION_ARGS(loc)); \
 } STMT_END
 
+/* now unused */
 #define	ckWARNregdep(loc,m) STMT_START {				    \
     __ASSERT_(PASS2) Perl_ck_warner_d(aTHX_ packWARN2(WARN_DEPRECATED,      \
                                                       WARN_REGEXP),         \
@@ -11641,10 +11642,9 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp, U32 depth)
                 && UCHARAT(RExC_parse-2) == '\\'
                 && strpbrk(RExC_parse-1, "NpPbBxog") == RExC_parse-1)
             {
-                ckWARNregdep(RExC_parse + 1,
-                            "Unescaped left brace in regex is "
-                            "deprecated here (and will be fatal "
-                            "in Perl 5.32), passed through");
+                ckWARNreg(RExC_parse + 1,
+                          "Unescaped left brace in regex is "
+                          "passed through");
             }
             /* Not bothering to indent here, as the above 'else' is temporary
              * */
@@ -13869,6 +13869,22 @@ S_regatom(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
                      * cperl special-cases only \NpPbBxog{} [cperl #362], later ({...}),
                      * all other cases are legal. */
 #ifndef USE_CPERL
+                    /* perl5 policy: */
+                    /* Trying to gain new uses for '{' without breaking too
+                     * much existing code is hard.  The solution currently
+                     * adopted is:
+                     *  1)  If there is no ambiguity that a '{' should always
+                     *      be taken literally, at the start of a construct, we
+                     *      just do so.
+                     *  2)  If the literal '{' conflicts with our desired use
+                     *      of it as a metacharacter, we die.  The deprecation
+                     *      cycles for this have come and gone.
+                     *  3)  If there is ambiguity, we raise a simple warning.
+                     *      This could happen, for example, if the user
+                     *      intended it to introduce a quantifier, but slightly
+                     *      misspelled the quantifier.  Without this warning,
+                     *      the quantifier would silently be taken as a literal
+                     *      string of characters instead of a meta construct */
 		    if (!(p - RExC_parse > 1
                           && UCHARAT(p-2) == '\\'
                           && strpbrk(p-1, "NpPbBxog") == p-1))
@@ -13886,10 +13902,8 @@ S_regatom(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
                             vFAIL("Unescaped left brace in regex is illegal here");
                         }
                         if (PASS2) {
-                            ckWARNregdep(p + 1,
-                                        "Unescaped left brace in regex is "
-                                        "deprecated here (and will be fatal "
-                                        "in Perl 5.30), passed through");
+                            ckWARNreg(p + 1, "Unescaped left brace in regex is"
+                                             " passed through");
                          }
 		    }
 #endif
@@ -14407,7 +14421,7 @@ S_regatom(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
         && UCHARAT(RExC_parse-2) == '\\'
         && strpbrk(RExC_parse-1, "NpPbBxog") == RExC_parse-1)  /* [cperl #362] */
     {
-        ckWARNregdep(RExC_parse + 1, "Unescaped left brace in regex is deprecated here (and will be fatal in Perl 5.30), passed through");
+        ckWARNreg(RExC_parse + 1, "Unescaped left brace in regex is passed through");
     }
 
     return(ret);

regcomp.c

@@ -663,6 +663,7 @@ my @warning_only_under_strict = (
     "/[$low_mixed_alpha-$high_mixed_alpha]/" => "Ranges of ASCII printables should be some subset of \"0-9\", \"A-Z\", or \"a-z\" {#} m/[$low_mixed_alpha-$high_mixed_alpha\{#}]/",
     "/[$low_mixed_digit-$high_mixed_digit]/" => "Ranges of ASCII printables should be some subset of \"0-9\", \"A-Z\", or \"a-z\" {#} m/[$low_mixed_digit-$high_mixed_digit\{#}]/",
     #'/\b<GCB}/' => 'Unescaped literal \'}\' {#} m/\b<GCB}{#}/',
+    '/\b<GCB}/' => '',
     '/[ ]def]/' => 'Unescaped literal \']\' {#} m/[ ]def]{#}/',
 );
 
@@ -694,13 +695,13 @@ my @deprecated = (
  '/^{/'          => "",
  '/foo|{/'       => "",
  '/foo|^{/'      => "",
- #'/foo({bar)/'   => 'Unescaped left brace in regex is deprecated here (and will be fatal in Perl 5.32), passed through {#} m/foo({{#}bar)/',
+ #'/foo({bar)/'   => 'Unescaped left brace in regex passed through {#} m/foo({{#}bar)/',
  '/foo(:?{bar)/' => "",
  '/\s*{/'        => "",
  '/a{3,4}{/'     => "",
- #'/.{/'         => 'Unescaped left brace in regex is deprecated here (and will be fatal in Perl 5.30), passed through {#} m/.{{#}/',
- #'/[x]{/'       => 'Unescaped left brace in regex is deprecated here (and will be fatal in Perl 5.30), passed through {#} m/[x]{{#}/',
- #'/\p{Latin}{/' => 'Unescaped left brace in regex is deprecated here (and will be fatal in Perl 5.30), passed through {#} m/\p{Latin}{{#}/',
+ #'/.{/'         => 'Unescaped left brace in regex passed through {#} m/.{{#}/',
+ #'/[x]{/'       => 'Unescaped left brace in regex passed through {#} m/[x]{{#}/',
+ #'/\p{Latin}{/' => 'Unescaped left brace in regex passed through {#} m/\p{Latin}{{#}/',
 );
 
 for my $strict ("", "use re 'strict';") {