Remove PointerIsValid()

This doesn't provide any value over the standard style of checking the
pointer directly or comparing against NULL.

Also remove related:
- AllocPointerIsValid() [unused]
- IndexScanIsValid() [had one user]
- HeapScanIsValid() [unused]
- InvalidRelation [unused]

Leaving HeapTupleIsValid(), ItemIdIsValid(), PortalIsValid(),
RelationIsValid for now, to reduce code churn.

Reviewed-by: Jacob Champion <jacob.champion@enterprisedb.com>
Discussion: https://www.postgresql.org/message-id/flat/ad50ab6b-6f74-4603-b099-1cd6382fb13d%40eisentraut.org
Discussion: https://www.postgresql.org/message-id/CA+hUKG+NFKnr=K4oybwDvT35dW=VAjAAfiuLxp+5JeZSOV3nBg@mail.gmail.com
Discussion: https://www.postgresql.org/message-id/bccf2803-5252-47c2-9ff0-340502d5bd1c@iki.fi

src/backend/access/common/reloptions.c

@@ -1179,7 +1179,7 @@ transformRelOptions(Datum oldOptions, List *defList, const char *nameSpace,
 	astate = NULL;
 
 	/* Copy any oldOptions that aren't to be replaced */
-	if (PointerIsValid(DatumGetPointer(oldOptions)))
+	if (DatumGetPointer(oldOptions) != NULL)
 	{
 		ArrayType  *array = DatumGetArrayTypeP(oldOptions);
 		Datum	   *oldoptions;
@@ -1357,7 +1357,7 @@ untransformRelOptions(Datum options)
 	int			i;
 
 	/* Nothing to do if no options */
-	if (!PointerIsValid(DatumGetPointer(options)))
+	if (DatumGetPointer(options) == NULL)
 		return result;
 
 	array = DatumGetArrayTypeP(options);
@@ -1549,7 +1549,7 @@ parseRelOptions(Datum options, bool validate, relopt_kind kind,
 	}
 
 	/* Done if no options */
-	if (PointerIsValid(DatumGetPointer(options)))
+	if (DatumGetPointer(options) != NULL)
 		parseRelOptionsInternal(options, validate, reloptions, numoptions);
 
 	*numrelopts = numoptions;
@@ -2092,7 +2092,7 @@ index_reloptions(amoptions_function amoptions, Datum reloptions, bool validate)
 	Assert(amoptions != NULL);
 
 	/* Assume function is strict */
-	if (!PointerIsValid(DatumGetPointer(reloptions)))
+	if (DatumGetPointer(reloptions) == NULL)
 		return NULL;
 
 	return amoptions(reloptions, validate);

src/backend/access/common/tupdesc.c

@@ -474,8 +474,8 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
 	/*
 	 * sanity checks
 	 */
-	Assert(PointerIsValid(src));
-	Assert(PointerIsValid(dst));
+	Assert(src);
+	Assert(dst);
 	Assert(srcAttno >= 1);
 	Assert(srcAttno <= src->natts);
 	Assert(dstAttno >= 1);
@@ -853,7 +853,7 @@ TupleDescInitEntry(TupleDesc desc,
 	/*
 	 * sanity checks
 	 */
-	Assert(PointerIsValid(desc));
+	Assert(desc);
 	Assert(attributeNumber >= 1);
 	Assert(attributeNumber <= desc->natts);
 	Assert(attdim >= 0);
@@ -925,7 +925,7 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	Form_pg_attribute att;
 
 	/* sanity checks */
-	Assert(PointerIsValid(desc));
+	Assert(desc);
 	Assert(attributeNumber >= 1);
 	Assert(attributeNumber <= desc->natts);
 	Assert(attdim >= 0);
@@ -1030,7 +1030,7 @@ TupleDescInitEntryCollation(TupleDesc desc,
 	/*
 	 * sanity checks
 	 */
-	Assert(PointerIsValid(desc));
+	Assert(desc);
 	Assert(attributeNumber >= 1);
 	Assert(attributeNumber <= desc->natts);
 

src/backend/access/index/indexam.c

@@ -75,7 +75,7 @@
 #define RELATION_CHECKS \
 do { \
 	Assert(RelationIsValid(indexRelation)); \
-	Assert(PointerIsValid(indexRelation->rd_indam)); \
+	Assert(indexRelation->rd_indam); \
 	if (unlikely(ReindexIsProcessingIndex(RelationGetRelid(indexRelation)))) \
 		ereport(ERROR, \
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED), \
@@ -85,9 +85,9 @@ do { \
 
 #define SCAN_CHECKS \
 ( \
-	AssertMacro(IndexScanIsValid(scan)), \
+	AssertMacro(scan), \
 	AssertMacro(RelationIsValid(scan->indexRelation)), \
-	AssertMacro(PointerIsValid(scan->indexRelation->rd_indam)) \
+	AssertMacro(scan->indexRelation->rd_indam) \
 )
 
 #define CHECK_REL_PROCEDURE(pname) \

src/backend/access/transam/xact.c

@@ -4535,13 +4535,13 @@ ReleaseSavepoint(const char *name)
 			break;
 	}
 
-	for (target = s; PointerIsValid(target); target = target->parent)
+	for (target = s; target; target = target->parent)
 	{
-		if (PointerIsValid(target->name) && strcmp(target->name, name) == 0)
+		if (target->name && strcmp(target->name, name) == 0)
 			break;
 	}
 
-	if (!PointerIsValid(target))
+	if (!target)
 		ereport(ERROR,
 				(errcode(ERRCODE_S_E_INVALID_SPECIFICATION),
 				 errmsg("savepoint \"%s\" does not exist", name)));
@@ -4565,7 +4565,7 @@ ReleaseSavepoint(const char *name)
 		if (xact == target)
 			break;
 		xact = xact->parent;
-		Assert(PointerIsValid(xact));
+		Assert(xact);
 	}
 }
 
@@ -4644,13 +4644,13 @@ RollbackToSavepoint(const char *name)
 			break;
 	}
 
-	for (target = s; PointerIsValid(target); target = target->parent)
+	for (target = s; target; target = target->parent)
 	{
-		if (PointerIsValid(target->name) && strcmp(target->name, name) == 0)
+		if (target->name && strcmp(target->name, name) == 0)
 			break;
 	}
 
-	if (!PointerIsValid(target))
+	if (!target)
 		ereport(ERROR,
 				(errcode(ERRCODE_S_E_INVALID_SPECIFICATION),
 				 errmsg("savepoint \"%s\" does not exist", name)));
@@ -4679,7 +4679,7 @@ RollbackToSavepoint(const char *name)
 			elog(FATAL, "RollbackToSavepoint: unexpected state %s",
 				 BlockStateAsString(xact->blockState));
 		xact = xact->parent;
-		Assert(PointerIsValid(xact));
+		Assert(xact);
 	}
 
 	/* And mark the target as "restart pending" */
@@ -5700,7 +5700,7 @@ ShowTransactionStateRec(const char *str, TransactionState s)
 	ereport(DEBUG5,
 			(errmsg_internal("%s(%d) name: %s; blockState: %s; state: %s, xid/subid/cid: %u/%u/%u%s%s",
 							 str, s->nestingLevel,
-							 PointerIsValid(s->name) ? s->name : "unnamed",
+							 s->name ? s->name : "unnamed",
 							 BlockStateAsString(s->blockState),
 							 TransStateAsString(s->state),
 							 (unsigned int) XidFromFullTransactionId(s->fullTransactionId),