Revert "Gut Perl_save_re_context"

This reverts commit b4fa55d3f12c6d98b13a8b3db4f8d921c8e56edc.

Turns out we need Perl_save_re_context() after all

1 files changed, 21 insertions, 3 deletions

diff --git a/regcomp.c b/regcomp.c
index 40336bf5f9..7bf630792b 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -17711,14 +17711,32 @@ S_re_croak2(pTHX_ bool utf8, const char* pat1,const char* pat2,...)
     Perl_croak(aTHX_ "%"UTF8f, UTF8fARG(utf8, l1-1, buf));
 }
 
-/* Get this:  We have an empty void function here.  But it somehow got into
-   the API, so there you go.  */
+/* XXX Here's a total kludge.  But we need to re-enter for swash routines. */
 
 #ifndef PERL_IN_XSUB_RE
 void
 Perl_save_re_context(pTHX)
 {
-    PERL_UNUSED_CONTEXT;
+    /* Save $1..$n (#18107: UTF-8 s/(\w+)/uc($1)/e); AMS 20021106. */
+    if (PL_curpm) {
+	const REGEXP * const rx = PM_GETRE(PL_curpm);
+	if (rx) {
+	    U32 i;
+	    for (i = 1; i <= RX_NPARENS(rx); i++) {
+		char digits[TYPE_CHARS(long)];
+		const STRLEN len = my_snprintf(digits, sizeof(digits),
+                                               "%lu", (long)i);
+		GV *const *const gvp
+		    = (GV**)hv_fetch(PL_defstash, digits, len, 0);
+
+		if (gvp) {
+		    GV * const gv = *gvp;
+		    if (SvTYPE(gv) == SVt_PVGV && GvSV(gv))
+			save_scalar(gv);
+		}
+	    }
+	}
+    }
 }
 #endif