Check the size in COPY_POINTER_FIELD

instead of making each caller do it.

Discussion: https://www.postgresql.org/message-id/flat/c1097590-a6a4-486a-64b1-e1f9cc0533ce@enterprisedb.com

src/backend/nodes/copyfuncs.c

@@ -57,8 +57,11 @@
 #define COPY_POINTER_FIELD(fldname, sz) \
 	do { \
 		Size	_size = (sz); \
-		newnode->fldname = palloc(_size); \
-		memcpy(newnode->fldname, from->fldname, _size); \
+		if (_size > 0) \
+		{ \
+			newnode->fldname = palloc(_size); \
+			memcpy(newnode->fldname, from->fldname, _size); \
+		} \
 	} while (0)
 
 /* Copy a parse location field (for Copy, this is same as scalar case) */
@@ -296,12 +299,9 @@ _copyRecursiveUnion(const RecursiveUnion *from)
 	 */
 	COPY_SCALAR_FIELD(wtParam);
 	COPY_SCALAR_FIELD(numCols);
-	if (from->numCols > 0)
-	{
-		COPY_POINTER_FIELD(dupColIdx, from->numCols * sizeof(AttrNumber));
-		COPY_POINTER_FIELD(dupOperators, from->numCols * sizeof(Oid));
-		COPY_POINTER_FIELD(dupCollations, from->numCols * sizeof(Oid));
-	}
+	COPY_POINTER_FIELD(dupColIdx, from->numCols * sizeof(AttrNumber));
+	COPY_POINTER_FIELD(dupOperators, from->numCols * sizeof(Oid));
+	COPY_POINTER_FIELD(dupCollations, from->numCols * sizeof(Oid));
 	COPY_SCALAR_FIELD(numGroups);
 
 	return newnode;
@@ -896,13 +896,10 @@ _copyMergeJoin(const MergeJoin *from)
 	COPY_SCALAR_FIELD(skip_mark_restore);
 	COPY_NODE_FIELD(mergeclauses);
 	numCols = list_length(from->mergeclauses);
-	if (numCols > 0)
-	{
-		COPY_POINTER_FIELD(mergeFamilies, numCols * sizeof(Oid));
-		COPY_POINTER_FIELD(mergeCollations, numCols * sizeof(Oid));
-		COPY_POINTER_FIELD(mergeStrategies, numCols * sizeof(int));
-		COPY_POINTER_FIELD(mergeNullsFirst, numCols * sizeof(bool));
-	}
+	COPY_POINTER_FIELD(mergeFamilies, numCols * sizeof(Oid));
+	COPY_POINTER_FIELD(mergeCollations, numCols * sizeof(Oid));
+	COPY_POINTER_FIELD(mergeStrategies, numCols * sizeof(int));
+	COPY_POINTER_FIELD(mergeNullsFirst, numCols * sizeof(bool));
 
 	return newnode;
 }
@@ -1064,12 +1061,9 @@ _copyAgg(const Agg *from)
 	COPY_SCALAR_FIELD(aggstrategy);
 	COPY_SCALAR_FIELD(aggsplit);
 	COPY_SCALAR_FIELD(numCols);
-	if (from->numCols > 0)
-	{
-		COPY_POINTER_FIELD(grpColIdx, from->numCols * sizeof(AttrNumber));
-		COPY_POINTER_FIELD(grpOperators, from->numCols * sizeof(Oid));
-		COPY_POINTER_FIELD(grpCollations, from->numCols * sizeof(Oid));
-	}
+	COPY_POINTER_FIELD(grpColIdx, from->numCols * sizeof(AttrNumber));
+	COPY_POINTER_FIELD(grpOperators, from->numCols * sizeof(Oid));
+	COPY_POINTER_FIELD(grpCollations, from->numCols * sizeof(Oid));
 	COPY_SCALAR_FIELD(numGroups);
 	COPY_SCALAR_FIELD(transitionSpace);
 	COPY_BITMAPSET_FIELD(aggParams);
@@ -1091,19 +1085,13 @@ _copyWindowAgg(const WindowAgg *from)
 
 	COPY_SCALAR_FIELD(winref);
 	COPY_SCALAR_FIELD(partNumCols);
-	if (from->partNumCols > 0)
-	{
-		COPY_POINTER_FIELD(partColIdx, from->partNumCols * sizeof(AttrNumber));
-		COPY_POINTER_FIELD(partOperators, from->partNumCols * sizeof(Oid));
-		COPY_POINTER_FIELD(partCollations, from->partNumCols * sizeof(Oid));
-	}
+	COPY_POINTER_FIELD(partColIdx, from->partNumCols * sizeof(AttrNumber));
+	COPY_POINTER_FIELD(partOperators, from->partNumCols * sizeof(Oid));
+	COPY_POINTER_FIELD(partCollations, from->partNumCols * sizeof(Oid));
 	COPY_SCALAR_FIELD(ordNumCols);
-	if (from->ordNumCols > 0)
-	{
-		COPY_POINTER_FIELD(ordColIdx, from->ordNumCols * sizeof(AttrNumber));
-		COPY_POINTER_FIELD(ordOperators, from->ordNumCols * sizeof(Oid));
-		COPY_POINTER_FIELD(ordCollations, from->ordNumCols * sizeof(Oid));
-	}
+	COPY_POINTER_FIELD(ordColIdx, from->ordNumCols * sizeof(AttrNumber));
+	COPY_POINTER_FIELD(ordOperators, from->ordNumCols * sizeof(Oid));
+	COPY_POINTER_FIELD(ordCollations, from->ordNumCols * sizeof(Oid));
 	COPY_SCALAR_FIELD(frameOptions);
 	COPY_NODE_FIELD(startOffset);
 	COPY_NODE_FIELD(endOffset);