save paren positions when running (?{}) code

Currently, all paren positions are saved before and after executing the
regops returned by (??{}); but not while the perl ops are being executed
beforehand. If the code happens to do a pattern match against the same
regex that's being currently run, then all iuts oparen positions will be
overwritten. So save them before entering the RUNOPS loop too.

diff --git a/regexec.c b/regexec.c
index a20b60a..2d86b0e 100644 (file)
--- a/regexec.c
+++ b/regexec.c
@@ -477,6 +477,18 @@ S_regcppop(pTHX_ regexp *rex)
 #endif
 }
 
+/* restore the parens and associated vars at savestack position ix,
+ * but without popping the stack */
+
+STATIC void
+S_regcp_restore(pTHX_ regexp *rex, I32 ix)
+{
+    I32 tmpix = PL_savestack_ix;
+    PL_savestack_ix = ix;
+    regcppop(rex);
+    PL_savestack_ix = tmpix;
+}
+
 #define regcpblow(cp) LEAVE_SCOPE(cp)  /* Ignores regcppush()ed data. */
 
 /*
@@ -3138,6 +3150,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, regnode *prog)
     I32 gimme = G_SCALAR;
     CV *caller_cv = NULL;      /* who called us */
     CV *last_pushed_cv = NULL; /* most recently called (?{}) CV */
+    CHECKPOINT runops_cp;      /* savestack position before executing EVAL */
 
 #ifdef DEBUGGING
     GET_RE_DEBUG_FLAGS_DECL;
@@ -4269,6 +4282,10 @@ S_regmatch(pTHX_ regmatch_info *reginfo, regnode *prog)
                struct re_save_state saved_state;
                CV *newcv;
 
+               /* save *all* paren positions */
+               regcppush(rex, 0);
+               REGCP_SET(runops_cp);
+
                /* To not corrupt the existing regex state while executing the
                 * eval we would normally put it on the save stack, like with
                 * save_re_context. However, re-evals have a weird scoping so we
@@ -4398,6 +4415,11 @@ S_regmatch(pTHX_ regmatch_info *reginfo, regnode *prog)
                PL_regeol = saved_regeol;
                if (!logical) {
                    /* /(?{...})/ */
+                   /* restore all paren positions. Note that where the
+                    * return value is used, we must delay this as the
+                    * returned string to be compiled may be $1 for
+                    * example */
+                   S_regcp_restore(aTHX_ rex, runops_cp);
                    sv_setsv(save_scalar(PL_replgv), ret);
                    break;
                }
@@ -4471,6 +4493,10 @@ S_regmatch(pTHX_ regmatch_info *reginfo, regnode *prog)
                            sv_magic(ret, MUTABLE_SV(rx), PERL_MAGIC_qr, 0, 0);
                        }
                        PL_regsize = osize;
+                       /* safe to do now that any $1 etc has been
+                        * interpolated into the new pattern string and
+                        * compiled */
+                       S_regcp_restore(aTHX_ rex, runops_cp);
                    }
                    re_sv = rx;
                    re = (struct regexp *)SvANY(rx);
@@ -4523,6 +4549,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, regnode *prog)
            }
            /* logical is 1,   /(?(?{...})X|Y)/ */
            sw = cBOOL(SvTRUE(ret));
+           S_regcp_restore(aTHX_ rex, runops_cp);
            logical = 0;
            break;
        }
@@ -5568,7 +5595,6 @@ NULL
            fake_end:
            if (cur_eval) {
                /* we've just finished A in /(??{A})B/; now continue with B */
-               I32 tmpix;
                st->u.eval.toggle_reg_flags
                            = cur_eval->u.eval.toggle_reg_flags;
                PL_reg_flags ^= st->u.eval.toggle_reg_flags; 
@@ -5586,10 +5612,7 @@ NULL
 
                /* Restore parens of the outer rex without popping the
                 * savestack */
-               tmpix = PL_savestack_ix;
-               PL_savestack_ix = cur_eval->u.eval.lastcp;
-               regcppop(rex);
-               PL_savestack_ix = tmpix;
+               S_regcp_restore(aTHX_ rex, cur_eval->u.eval.lastcp);
 
                st->u.eval.prev_eval = cur_eval;
                cur_eval = cur_eval->u.eval.prev_eval;

diff --git a/t/re/pat_re_eval.t b/t/re/pat_re_eval.t
index 20dbf06..338f5c2 100644 (file)
--- a/t/re/pat_re_eval.t
+++ b/t/re/pat_re_eval.t
@@ -23,7 +23,7 @@ BEGIN {
 }
 
 
-plan tests => 434;  # Update this when adding/deleting tests.
+plan tests => 444;  # Update this when adding/deleting tests.
 
 run_tests() unless caller;
 
@@ -835,6 +835,88 @@ sub run_tests {
        recurse2(5);
     }
 
+    # nested (??{}) called from various levels of a recursive function
+
+    {
+       sub recurse3 {
+           my ($n) = @_;
+           return if $n > 3;
+           ok("A$n" =~ m{^A(??{ "0123" =~ /((??{$n}))/; $1 })$},
+               "recurse3($n)");
+           ok("A$n" !~ m{^A(??{ "0123" =~ /((??{$n}))/; "X" })$},
+               "recurse3($n) nomatch");
+           recurse3($n+1);
+       }
+       recurse3(0);
+    }
+
+    # nested (??{}) being invoked recursively via a function
+
+    {
+       my $s = '';
+       our $recurse4;
+       my @alpha = qw(A B C D E);
+       $recurse4 = sub {
+           my ($n) = @_;
+           $s .= "(n=$n:";
+           if ($n < 4) {
+               my $m = ("$alpha[$n]" . substr("0123", 0, $n+1)) =~
+                   m{^([A-Z])
+                     (??{
+                           $s .= "1=$1:";
+                           "$n-0123" =~ m{^(\d)-(((??{$recurse4->($n+1)})))};
+                           $s .= "i1=$1:<=[$2]";
+                           $3; # NB - not stringified
+                      })
+                      $
+                    }x;
+               $s .= "1a=$1:";
+               $s .= $m ? 'M' : '!M';
+           }
+           my $ret =  '.*?' . ($n-1);
+           $s .= "<=[$ret])";
+           return $ret;
+       };
+       $recurse4->(0);
+       my $exp =   '(n=0:1=A:(n=1:1=B:(n=2:1=C:(n=3:1=D:(n=4:<=[.*?3])'
+                 . 'i1=3:<=[0123]1a=D:M<=[.*?2])i1=2:<=[012]1a=C:M<=[.*?1])'
+                 . 'i1=1:<=[01]1a=B:M<=[.*?0])i1=0:<=[0]1a=A:M<=[.*?-1])';
+       is($s, $exp, 'recurse4');
+    }
+
+    # single (??{}) being invoked recursively via a function
+
+    {
+       my $s = '';
+       our $recurse5;
+       my @alpha = qw(A B C D E);
+       $recurse5 = sub {
+           my ($n) = @_;
+           $s .= "(n=$n:";
+           if ($n < 4) {
+               my $m = ("$alpha[$n]" . substr("0123", 0, $n+1)) =~
+                   m{^([A-Z])
+                     ((??{
+                           $s .= "1=$1:";
+                           $recurse5->($n+1);
+                      }))
+                      $
+                    }x;
+               $s .= "1a=$1:2=$2:";
+               $s .= $m ? 'M' : '!M';
+           }
+           my $ret =  '.*?' . ($n-1);
+           $s .= "<=[$ret])";
+           return $ret;
+       };
+       $recurse5->(0);
+       my $exp =   '(n=0:1=A:(n=1:1=B:(n=2:1=C:(n=3:1=D:(n=4:<=[.*?3])'
+                 . '1a=D:2=0123:M<=[.*?2])1a=C:2=012:M<=[.*?1])'
+                 . '1a=B:2=01:M<=[.*?0])1a=A:2=0:M<=[.*?-1])';
+       is($s, $exp, 'recurse5');
+    }
+
+
     # make sure that errors during compiling run-time code get trapped
 
     {