Add checking to weakptr functions

src/weakptr.c

@@ -201,6 +201,11 @@ Int LengthWPObj(Obj wp)
 
 Obj FuncLengthWPObj(Obj self, Obj wp)
 {
+  if (TNUM_OBJ(wp) != T_WPOBJ)
+    {
+      ErrorMayQuit("LengthWPObj: argument must be a weak pointer object, not a %s",
+                   (Int)TNAM_OBJ(wp), 0);
+    }
   return INTOBJ_INT(LengthWPObj(wp));
 }
 
@@ -216,7 +221,24 @@ Obj FuncLengthWPObj(Obj self, Obj wp)
 
 Obj FuncSetElmWPObj(Obj self, Obj wp, Obj pos, Obj val)
 {
+  if (TNUM_OBJ(wp) != T_WPOBJ)
+    {
+      ErrorMayQuit("SetElmWPObj: First argument must be a weak pointer object, not a %s",
+                   (Int)TNAM_OBJ(wp), 0);
+    }
+
+  if (!IS_INTOBJ(pos))
+    {
+      ErrorMayQuit("SetElmWPObj: Position must be a small integer, not a %s",
+                (Int)TNAM_OBJ(pos),0L);
+    }
+
   UInt ipos = INT_INTOBJ(pos);
+  if (ipos < 1)
+    {
+      ErrorMayQuit("SetElmWPObj: Position must be a positive integer",0L,0L);
+    }
+
   if (LengthWPObj(wp)  < ipos)
     {
       GROW_WPOBJ(wp, ipos);
@@ -239,7 +261,24 @@ Obj FuncSetElmWPObj(Obj self, Obj wp, Obj pos, Obj val)
 
 Int IsBoundElmWPObj( Obj wp, Obj pos)
 {
+  if (TNUM_OBJ(wp) != T_WPOBJ)
+    {
+      ErrorMayQuit("IsBoundElmWPObj: First argument must be a weak pointer object, not a %s",
+                   (Int)TNAM_OBJ(wp), 0);
+    }
+
+  if (!IS_INTOBJ(pos))
+    {
+      ErrorMayQuit("IsBoundElmWPObj: Position must be a small integer, not a %s",
+                (Int)TNAM_OBJ(pos),0L);
+    }
+
   UInt ipos = INT_INTOBJ(pos);
+  if (ipos < 1)
+    {
+      ErrorMayQuit("IsBoundElmWPObj: Position must be a positive integer",0L,0L);
+    }
+
   Obj elm;
   if ( LengthWPObj(wp) < ipos ) 
     {
@@ -282,9 +321,27 @@ Obj FuncIsBoundElmWPObj( Obj self, Obj wp, Obj pos)
 
 Obj FuncUnbindElmWPObj( Obj self, Obj wp, Obj pos)
 {
+  if (TNUM_OBJ(wp) != T_WPOBJ)
+    {
+      ErrorMayQuit("UnbindElmWPObj: First argument must be a weak pointer object, not a %s",
+                   (Int)TNAM_OBJ(wp), 0);
+    }
+
+  if (!IS_INTOBJ(pos))
+    {
+      ErrorMayQuit("UnbindElmWPObj: Position must be a small integer, not a %s",
+                (Int)TNAM_OBJ(pos),0L);
+    }
+
+  UInt ipos = INT_INTOBJ(pos);
+  if (ipos < 1)
+    {
+      ErrorMayQuit("UnbindElmWPObj: Position must be a positive integer",0L,0L);
+    }
+
   Int len = LengthWPObj(wp);
-  if ( INT_INTOBJ(pos) <= len ) {
-    ELM_WPOBJ( wp, INT_INTOBJ(pos)) =  0;
+  if ( ipos <= len ) {
+    ELM_WPOBJ( wp, ipos) =  0;
   }
   return 0;
 }
@@ -306,7 +363,25 @@ Obj FuncUnbindElmWPObj( Obj self, Obj wp, Obj pos)
 Obj FuncElmWPObj( Obj self, Obj wp, Obj pos)
 {
   Obj elm;
+
+  if (TNUM_OBJ(wp) != T_WPOBJ)
+    {
+      ErrorMayQuit("ElmWPObj: First argument must be a weak pointer object, not a %s",
+                   (Int)TNAM_OBJ(wp), 0);
+    }
+
+  if (!IS_INTOBJ(pos))
+    {
+      ErrorMayQuit("ElmWPObj: Position must be a small integer, not a %s",
+                (Int)TNAM_OBJ(pos),0L);
+    }
+
   UInt ipos = INT_INTOBJ(pos);
+  if (ipos < 1)
+    {
+      ErrorMayQuit("ElmWPObj: Position must be a positive integer",0L,0L);
+    }
+
   if ( STORED_LEN_WPOBJ(wp) < ipos ) 
     {
       return Fail;

tst/testinstall/weakptr-badargs.tst

@@ -0,0 +1,46 @@
+#############################################################################
+gap> START_TEST("weakptr-badargs.tst");
+gap> w := WeakPointerObject([1,,3,4]);
+Error, Variable: 'WeakPointerObject' must have a value
+gap> w := WeakPointerObj([1,,3,4]);;
+gap> SetElmWPObj(w, 0, 0);
+Error, SetElmWPObj: Position must be a positive integer
+gap> SetElmWPObj(w, [1,2], 0);
+Error, SetElmWPObj: Position must be a small integer, not a list (plain,cyc)
+gap> SetElmWPObj(w, (), 0);
+Error, SetElmWPObj: Position must be a small integer, not a permutation (small\
+)
+gap> SetElmWPObj((), 1, 1);
+Error, SetElmWPObj: First argument must be a weak pointer object, not a permut\
+ation (small)
+gap> UnbindElmWPObj(w, 0);
+Error, UnbindElmWPObj: Position must be a positive integer
+gap> UnbindElmWPObj(w, []);
+Error, UnbindElmWPObj: Position must be a small integer, not a list (plain,emp\
+ty)
+gap> UnbindElmWPObj([], 2);
+Error, UnbindElmWPObj: First argument must be a weak pointer object, not a lis\
+t (plain,empty)
+gap> ElmWPObj(w, 0);
+Error, ElmWPObj: Position must be a positive integer
+gap> ElmWPObj(w, []);
+Error, ElmWPObj: Position must be a small integer, not a list (plain,empty)
+gap> ElmWPObj([], 1);
+Error, ElmWPObj: First argument must be a weak pointer object, not a list (pla\
+in,empty)
+gap> IsBoundWPObj(w, 0);
+Error, Variable: 'IsBoundWPObj' must have a value
+gap> IsBoundElmWPObj(w, 0);
+Error, IsBoundElmWPObj: Position must be a positive integer
+gap> IsBoundElmWPObj(w, []);
+Error, IsBoundElmWPObj: Position must be a small integer, not a list (plain,em\
+pty)
+gap> IsBoundElmWPObj([], 1);
+Error, IsBoundElmWPObj: First argument must be a weak pointer object, not a li\
+st (plain,empty)
+gap> LengthWPObj([]);
+Error, LengthWPObj: argument must be a weak pointer object, not a list (plain,\
+empty)
+gap> LengthWPObj(0);
+Error, LengthWPObj: argument must be a weak pointer object, not a integer
+gap> STOP_TEST( "weakptr-badargs.tst", 100);