magic_setisa enhanced to update %FIELDS automatically when @ISA

is assigned to. Added tests to t/op/array.t. magic_setisa now
warns about including non-existent packages in @ISA when -w is on.

p4raw-id: //depot/perl@264

1 files changed, 47 insertions, 0 deletions

diff --git a/mg.c b/mg.c
index e2ecdf975d..97e9d99af0 100644
--- a/mg.c
+++ b/mg.c
@@ -838,7 +838,54 @@ magic_setsig(SV *sv, MAGIC *mg)
 int
 magic_setisa(SV *sv, MAGIC *mg)
 {
+    HV *stash;
+    SV **svp;
+    I32 fill;
+    HV *basefields = Nullhv;
+    GV **gvp;
+    GV *gv;
+    HE *he;
+    static char *FIELDS = "FIELDS";
+
     sub_generation++;
+
+    if (mg->mg_type == 'i')
+	return 0;	/* Ignore lower-case version of the magic */
+
+    stash = GvSTASH(mg->mg_obj);
+    svp = AvARRAY((AV*)sv);
+    
+    for (fill = AvFILL((AV*)sv); fill >= 0; fill--, svp++) {
+	HV *basestash = gv_stashsv(*svp, FALSE);
+
+	if (!basestash) {
+	    if (dowarn)
+		warn("No such package \"%_\" in @ISA assignment", *svp);
+	    continue;
+	}
+	gvp = (GV**)hv_fetch(basestash, FIELDS, 6, FALSE);
+	if (gvp && *gvp && GvHV(*gvp)) {
+	    if (basefields)
+		croak("Can't multiply inherit %%FIELDS");
+	    basefields = GvHV(*gvp);
+	}
+    }
+
+    if (!basefields)
+	return 0;
+    
+    gv = (GV*)*hv_fetch(stash, FIELDS, 6, TRUE);
+    if (!isGV(gv))
+	gv_init(gv, stash, FIELDS, 6, TRUE);
+    if (!GvHV(gv))
+	GvHV(gv) = newHV();
+    if (HvKEYS(GvHV(gv)))
+	croak("Inherited %%FIELDS can't override existing %%FIELDS");
+
+    hv_iterinit(GvHV(gv));
+    while ((he = hv_iternext(basefields)))
+	hv_store(GvHV(gv), HeKEY(he), HeKLEN(he), HeVAL(he), HeHASH(he));
+
     return 0;
 }