fixes for overloading bugs and docs, tweaked some

	Message-Id: <199807260128.VAA10543@monk.mps.ohio-state.edu>
	Subject: [PATCH 5.004_76] better overloading

p4raw-id: //depot/maint-5.005/perl@1677

1 files changed, 32 insertions, 9 deletions

diff --git a/gv.c b/gv.c
index e8a2f9d82e..a01956fd25 100644
--- a/gv.c
+++ b/gv.c
@@ -1154,7 +1154,7 @@ amagic_call(SV *left, SV *right, int method, int flags)
   CV **cvp=NULL, **ocvp=NULL;
   AMT *amtp, *oamtp;
   int fl=0, off, off1, lr=0, assign=AMGf_assign & flags, notfound=0;
-  int postpr=0, inc_dec_ass=0, assignshift=assign?1:0;
+  int postpr = 0, force_cpy = 0, assignshift = assign ? 1 : 0;
   HV* stash;
   if (!(AMGf_noleft & flags) && SvAMAGIC(left)
       && (mg = mg_find((SV*)(stash=SvSTASH(SvRV(left))),'c'))
@@ -1171,16 +1171,19 @@ amagic_call(SV *left, SV *right, int method, int flags)
       int logic;
 
       /* look for substituted methods */
+      /* In all the covered cases we should be called with assign==0. */
 	 switch (method) {
 	 case inc_amg:
-	   if (((cv = cvp[off=add_ass_amg]) && (inc_dec_ass=1))
-	       || ((cv = cvp[off=add_amg]) && (postpr=1))) {
+	   force_cpy = 1;
+	   if ((cv = cvp[off=add_ass_amg])
+	       || ((cv = cvp[off = add_amg]) && (force_cpy = 0, postpr = 1))) {
 	     right = &PL_sv_yes; lr = -1; assign = 1;
 	   }
 	   break;
 	 case dec_amg:
-	   if (((cv = cvp[off=subtr_ass_amg])  && (inc_dec_ass=1))
-	       || ((cv = cvp[off=subtr_amg]) && (postpr=1))) {
+	   force_cpy = 1;
+	   if ((cv = cvp[off = subtr_ass_amg])
+	       || ((cv = cvp[off = subtr_amg]) && (force_cpy = 0, postpr=1))) {
 	     right = &PL_sv_yes; lr = -1; assign = 1;
 	   }
 	   break;
@@ -1327,6 +1330,7 @@ amagic_call(SV *left, SV *right, int method, int flags)
 	}
 	return NULL;
       }
+      force_cpy = force_cpy || assign;
     }
   }
   if (!notfound) {
@@ -1343,14 +1347,33 @@ amagic_call(SV *left, SV *right, int method, int flags)
 		 flags & AMGf_unary? " for argument" : "",
 		 HvNAME(stash), 
 		 fl? ",\n\tassignment variant used": "") );
+  }
     /* Since we use shallow copy during assignment, we need
      * to dublicate the contents, probably calling user-supplied
      * version of copy operator
      */
-    if ((method + assignshift==off 
-	 && (assign || method==inc_amg || method==dec_amg))
-	|| inc_dec_ass) RvDEEPCP(left);
-  }
+    /* We need to copy in following cases:
+     * a) Assignment form was called.
+     * 		assignshift==1,  assign==T, method + 1 == off
+     * b) Increment or decrement, called directly.
+     * 		assignshift==0,  assign==0, method + 0 == off
+     * c) Increment or decrement, translated to assignment add/subtr.
+     * 		assignshift==0,  assign==T, 
+     *		force_cpy == T
+     * d) Increment or decrement, translated to nomethod.
+     * 		assignshift==0,  assign==0, 
+     *		force_cpy == T
+     * e) Assignment form translated to nomethod.
+     * 		assignshift==1,  assign==T, method + 1 != off
+     *		force_cpy == T
+     */
+    /*	off is method, method+assignshift, or a result of opcode substitution.
+     *	In the latter case assignshift==0, so only notfound case is important.
+     */
+  if (( (method + assignshift == off)
+	&& (assign || (method == inc_amg) || (method == dec_amg)))
+      || force_cpy)
+    RvDEEPCP(left);
   {
     dSP;
     BINOP myop;