PATCH: [perl #117327]: Sequence (?#...) not recognized in regex

This reverts commit 504858073fe16afb61d66a8b6748851780e51432, which
was made under the erroneous belief that certain code was unreachable.
This code appears to be reachable, however, only if the input has
a 2-character lexical token split by space or a comment.  The token
should be indivisible, and was accepted only through an accident of
implementation.  A later commit will deprecate splitting it, with the
view of eventually making splitting it a fatal error.  In the meantime,
though, this reverts to the original behavior, and adds a (temporary)
test to verify that.

diff --git a/regcomp.c b/regcomp.c
index 0840778..95f8958 100644 (file)
--- a/regcomp.c
+++ b/regcomp.c
@@ -8898,6 +8898,18 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
            case '@':           /* (?@...) */
                vFAIL2("Sequence (?%c...) not implemented", (int)paren);
                break;
+            case '#':           /* (?#...) */
+                /* XXX As soon as we disallow separating the '?' and '*' (by
+                 * spaces or (?#...) comment), it is believed that this case
+                 * will be unreachable and can be removed.  See
+                 * [perl #117327] */
+                while (*RExC_parse && *RExC_parse != ')')
+                   RExC_parse++;
+               if (*RExC_parse != ')')
+                   FAIL("Sequence (?#... not terminated");
+               nextchar(pRExC_state);
+               *flagp = TRYAGAIN;
+               return NULL;
            case '0' :           /* (?0) */
            case 'R' :           /* (?R) */
                if (*RExC_parse != ')')

diff --git a/t/re/pat.t b/t/re/pat.t
index 11ae2d3..05bb650 100644 (file)
--- a/t/re/pat.t
+++ b/t/re/pat.t
@@ -20,7 +20,7 @@ BEGIN {
     require './test.pl';
 }
 
-plan tests => 466;  # Update this when adding/deleting tests.
+plan tests => 467;  # Update this when adding/deleting tests.
 
 run_tests() unless caller;
 
@@ -1342,6 +1342,13 @@ EOP
        ok("Perl" =~ /P.*$/i, '#116148');
     }
 
+    { # 117327: Sequence (?#...) not recognized in regex
+      # The space between the '(' and '?' is now deprecated; this test should
+      # be removed when the deprecation is made fatal.
+        no warnings;
+        like("ab", qr/a( ?#foo)b/x);
+    }
+
 
 } # End of sub run_tests