A more reliable logic for turning off the GMAGICAL flag when no uvar magic is involved

diff --git a/Magic.xs b/Magic.xs
index 73536b861649b32eb497cc082f611ba15e567fdc..dfce918d55c300915f07bcf212a47e538912462d 100644 (file)
--- a/Magic.xs
+++ b/Magic.xs
@@ -325,6 +325,7 @@ STATIC UV vmg_cast(pTHX_ SV *sv, SV *wiz, AV *args) {
  MAGIC *mg = NULL, *moremagic = NULL;
  MGWIZ *w;
  SV *data;
+ U32 oldgmg = SvGMAGICAL(sv);
 
  w = SV2MGWIZ(wiz);
 
@@ -355,10 +356,18 @@ STATIC UV vmg_cast(pTHX_ SV *sv, SV *wiz, AV *args) {
  if (SvTYPE(sv) < SVt_PVHV)
   goto done;
 
+ /* The GMAGICAL flag only says that a hash is tied or has uvar magic - get
+  * magic is actually never called for them. If the GMAGICAL flag was off before
+  * calling sv_magicext(), the hash isn't tied and has no uvar magic. If it's
+  * now on, then this wizard has get magic. Hence we can work around the
+  * get/clear shortcoming by turning the GMAGICAL flag off. If the current magic
+  * has uvar callbacks, it will be turned back on later. */
+ if (!oldgmg && SvGMAGICAL(sv))
+  SvGMAGICAL_off(sv);
+
 #if VMG_UVAR
  if (w->uvar) {
   MAGIC *prevmagic;
-  int add_uvar = 1;
   struct ufuncs uf[2];
 
   uf[0].uf_val   = vmg_svt_val;
@@ -377,24 +386,19 @@ STATIC UV vmg_cast(pTHX_ SV *sv, SV *wiz, AV *args) {
   if (mg) { /* Found another uvar magic. */
    struct ufuncs *olduf = (struct ufuncs *) mg->mg_ptr;
    if (olduf->uf_val == vmg_svt_val) {
-    /* It's our uvar magic, nothing to do. */
-    add_uvar = 0;
+    /* It's our uvar magic, nothing to do. oldgmg was true. */
+    goto done;
    } else {
     /* It's another uvar magic, backup it and replace it by ours. */
     uf[1] = *olduf;
     vmg_uvar_del(sv, prevmagic, mg, moremagic);
    }
-  } else if (w->cb_get)
-   SvGMAGICAL_off(sv);
-
-  if (add_uvar) {
-   vmg_sv_magicuvar(sv, (const char *) &uf, sizeof(uf));
   }
 
+  vmg_sv_magicuvar(sv, (const char *) &uf, sizeof(uf));
+  /* Our hash now carries uvar magic. The uvar/clear shortcoming has to be
+   * handled by our uvar callback. */
  }
-#else
- if (w->cb_get)
-  SvGMAGICAL_off(sv);
 #endif /* VMG_UVAR */
 
 done: