regcomp.c: Consolidate 2nd pass for warnings

Warnings have to generally be delayed being output until the 2nd pass,
as the first pass can be restarted multiple times, and so the same
warning could be output multiple times if the restarted code outputs a
warning.

Prior to this commit, there was an assert that the warnings are being
output in the 2nd pass.  This commit changes it so that the assert is
turned into an 'if' in common code, and the dispersed 'if's that
formerly were used are removed as much as possible.  If that removes an
indented block, this commit also outdents the block contents.

1 files changed, 24 insertions, 36 deletions

diff --git a/regcomp.c b/regcomp.c
index c8c7ceca13..f5f48fd9a6 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -791,14 +791,17 @@ static const scan_data_t zero_scan_data = {
             REPORT_LOCATION_ARGS(RExC_parse));          \
 } STMT_END
 
-/* This has an assert in it because of [perl #122671] Many warnings in
- * regcomp.c can occur twice.  If they get output in pass1 and later in that
- * pass, the pattern has to be converted to UTF-8 and the pass restarted, they
- * would get output again.  So they should be output in pass2, and this
- * assert makes sure new warnings follow that paradigm. */
+/* Outputting warnings is generally deferred until the 2nd pass.  This is
+ * because the first pass can be restarted, for example if the pattern has to
+ * be converted to UTF-8.  If a warning had already been output earlier in the
+ * pass, it would be re-output after the restart.  Pass 2 is never restarted,
+ * so the problem simply goes away if we defer the output to that pass.  See
+ * [perl #122671]. */
 #define _WARN_HELPER(loc, warns, code)                                  \
     STMT_START {                                                        \
-        __ASSERT_(PASS2) code;                                          \
+        if (PASS2) {                                                    \
+            code;                                                       \
+        }                                                               \
     } STMT_END
 
 /* m is not necessarily a "literal string", in this macro */
@@ -10611,8 +10614,7 @@ S_parse_lparen_question_flags(pTHX_ RExC_state_t *pRExC_state)
                 break;
             case KEEPCOPY_PAT_MOD: /* 'p' */
                 if (flagsp == &negflags) {
-                    if (PASS2)
-                        ckWARNreg(RExC_parse + 1,"Useless use of (?-p)");
+                    ckWARNreg(RExC_parse + 1,"Useless use of (?-p)");
                 } else {
                     *flagsp |= RXf_PMf_KEEPCOPY;
                 }
@@ -10976,11 +10978,9 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp, U32 depth)
 
                     /* By doing this here, we avoid extra warnings for nested
                      * script runs */
-                    if (PASS2) {
                     ckWARNexperimental(RExC_parse,
                         WARN_EXPERIMENTAL__SCRIPT_RUN,
                         "The script_run feature is experimental");
-                    }
 
                     if (paren == 's') {
                         /* Here, we're starting a new regular script run */
@@ -11021,12 +11021,9 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp, U32 depth)
                 /*FALLTHROUGH*/
 
             alpha_assertions:
-
-                if (PASS2) {
                 ckWARNexperimental(RExC_parse,
                         WARN_EXPERIMENTAL__ALPHA_ASSERTIONS,
                         "The alpha_assertions feature is experimental");
-                }
 
                 RExC_seen_zerolen++;
 
@@ -11687,7 +11684,7 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp, U32 depth)
             } /* end switch */
 	}
 	else {
-            if (*RExC_parse == '{' && PASS2) {
+            if (*RExC_parse == '{') {
                 ckWARNregdep(RExC_parse + 1,
                             "Unescaped left brace in regex is "
                             "deprecated here (and will be fatal "
@@ -12159,11 +12156,9 @@ S_regpiece(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
             }
             else if (min == max && *RExC_parse == '?')
             {
-                if (PASS2) {
-                    ckWARN2reg(RExC_parse + 1,
-                               "Useless use of greediness modifier '%c'",
-                               *RExC_parse);
-                }
+                ckWARN2reg(RExC_parse + 1,
+                           "Useless use of greediness modifier '%c'",
+                           *RExC_parse);
             }
 
 	  do_curly:
@@ -13860,8 +13855,7 @@ S_regatom(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
 				REQUIRE_UTF8(flagp);
 			    }
 			    p += numlen;
-                            if (PASS2   /* like \08, \178 */
-                                && numlen < 3
+                            if (   numlen < 3 /* like \08, \178 */
                                 && isDIGIT(*p) && ckWARN(WARN_REGEXP))
                             {
 				reg_warn_non_literal_string(
@@ -13875,7 +13869,7 @@ S_regatom(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
 			    FAIL("Trailing \\");
 			/* FALLTHROUGH */
 		    default:
-			if (!SIZE_ONLY&& isALPHANUMERIC(*p)) {
+			if (isALPHANUMERIC(*p)) {
 			    /* Include any left brace following the alpha to emphasize
 			     * that it could be part of an escape at some point
 			     * in the future */
@@ -13912,15 +13906,13 @@ S_regatom(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
                             vFAIL("Unescaped left brace in regex is "
                                   "illegal here");
                         }
-                        if (PASS2) {
-                            ckWARNreg(p + 1, "Unescaped left brace in regex is"
-                                             " passed through");
-                        }
+                        ckWARNreg(p + 1, "Unescaped left brace in regex is"
+                                         " passed through");
 		    }
 		    goto normal_default;
                 case '}':
                 case ']':
-                    if (PASS2 && p > RExC_parse && RExC_strict) {
+                    if (p > RExC_parse && RExC_strict) {
                         ckWARN2reg(p + 1, "Unescaped literal '%c'", *p);
                     }
 		    /*FALLTHROUGH*/
@@ -16277,11 +16269,9 @@ S_add_above_Latin1_folds(pTHX_ RExC_state_t *pRExC_state, const U8 cp, SV** invl
 
                 /* Use deprecated warning to increase the chances of this being
                  * output */
-                if (PASS2) {
-                    ckWARN2reg_d(RExC_parse,
+                ckWARN2reg_d(RExC_parse,
                         "Perl folding rules are not up-to-date for 0x%02X;"
                         " please use the perlbug utility to report;", cp);
-                }
             }
             else {
                 unsigned int i;
@@ -16774,10 +16764,8 @@ S_regclass(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth,
                             vFAIL("\\N in a character class must be a named character: \\N{...}");
                         }
                         else if (cp_count == 0) {
-                            if (PASS2) {
-                                ckWARNreg(RExC_parse,
-                                        "Ignoring zero length \\N{} in character class");
-                            }
+                            ckWARNreg(RExC_parse,
+                              "Ignoring zero length \\N{} in character class");
                         }
                         else { /* cp_count > 1 */
                             if (! RExC_in_multi_char_class) {
@@ -16786,7 +16774,7 @@ S_regclass(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth,
                                         RExC_parse--;
                                         vFAIL("\\N{} in inverted character class or as a range end-point is restricted to one character");
                                     }
-                                    else if (PASS2) {
+                                    else {
                                         ckWARNreg(RExC_parse, "Using just the first character returned by \\N{} in character class");
                                     }
                                     break; /* <value> contains the first code
@@ -17412,7 +17400,7 @@ S_regclass(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth,
                                 vFAIL4("False [] range \"%*.*s\"",
                                     w, w, rangebegin);
                             }
-                            else if (PASS2) {
+                            else {
                                 vWARN4(RExC_parse,
                                     "False [] range \"%*.*s\"",
                                     w, w, rangebegin);