Cast result of copyObject() to correct type

copyObject() is declared to return void *, which allows easily assigning
the result independent of the input, but it loses all type checking.

If the compiler supports typeof or something similar, cast the result to
the input type.  This creates a greater amount of type safety.  In some
cases, where the result is assigned to a generic type such as Node * or
Expr *, new casts are now necessary, but in general casts are now
unnecessary in the normal case and indicate that something unusual is
happening.

Reviewed-by: Mark Dilger <hornschnorter@gmail.com>

Author: petere

config/c-compiler.m4

@@ -178,6 +178,33 @@ fi])# PGAC_C_STATIC_ASSERT
 
 
 
+# PGAC_C_TYPEOF
+# -------------
+# Check if the C compiler understands typeof or a variant.  Define
+# HAVE_TYPEOF if so, and define 'typeof' to the actual key word.
+#
+AC_DEFUN([PGAC_C_TYPEOF],
+[AC_CACHE_CHECK(for typeof, pgac_cv_c_typeof,
+[pgac_cv_c_typeof=no
+for pgac_kw in typeof __typeof__ decltype; do
+  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([],
+[int x = 0;
+$pgac_kw(x) y;
+y = x;
+return y;])],
+[pgac_cv_c_typeof=$pgac_kw])
+  test "$pgac_cv_c_typeof" != no && break
+done])
+if test "$pgac_cv_c_typeof" != no; then
+  AC_DEFINE(HAVE_TYPEOF, 1,
+            [Define to 1 if your compiler understands `typeof' or something similar.])
+  if test "$pgac_cv_c_typeof" != typeof; then
+    AC_DEFINE(typeof, $pgac_cv_c_typeof, [Define to how the compiler spells `typeof'.])
+  fi
+fi])# PGAC_C_TYPEOF
+
+
+
 # PGAC_C_TYPES_COMPATIBLE
 # -----------------------
 # Check if the C compiler understands __builtin_types_compatible_p,

configure

@@ -11667,6 +11667,46 @@ if test x"$pgac_cv__static_assert" = xyes ; then
 
 $as_echo "#define HAVE__STATIC_ASSERT 1" >>confdefs.h
 
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for typeof" >&5
+$as_echo_n "checking for typeof... " >&6; }
+if ${pgac_cv_c_typeof+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  pgac_cv_c_typeof=no
+for pgac_kw in typeof __typeof__ decltype; do
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+int x = 0;
+$pgac_kw(x) y;
+y = x;
+return y;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  pgac_cv_c_typeof=$pgac_kw
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+  test "$pgac_cv_c_typeof" != no && break
+done
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $pgac_cv_c_typeof" >&5
+$as_echo "$pgac_cv_c_typeof" >&6; }
+if test "$pgac_cv_c_typeof" != no; then
+
+$as_echo "#define HAVE_TYPEOF 1" >>confdefs.h
+
+  if test "$pgac_cv_c_typeof" != typeof; then
+
+$as_echo "#define typeof \$pgac_cv_c_typeof" >>confdefs.h
+
+  fi
 fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for __builtin_types_compatible_p" >&5
 $as_echo_n "checking for __builtin_types_compatible_p... " >&6; }

configure.in

@@ -1330,6 +1330,7 @@ AC_C_FLEXIBLE_ARRAY_MEMBER
 PGAC_C_SIGNED
 PGAC_C_FUNCNAME_SUPPORT
 PGAC_C_STATIC_ASSERT
+PGAC_C_TYPEOF
 PGAC_C_TYPES_COMPATIBLE
 PGAC_C_BUILTIN_BSWAP32
 PGAC_C_BUILTIN_BSWAP64

src/backend/bootstrap/bootstrap.c

@@ -1082,11 +1082,11 @@ index_register(Oid heap,
 
 	memcpy(newind->il_info, indexInfo, sizeof(IndexInfo));
 	/* expressions will likely be null, but may as well copy it */
-	newind->il_info->ii_Expressions = (List *)
+	newind->il_info->ii_Expressions =
 		copyObject(indexInfo->ii_Expressions);
 	newind->il_info->ii_ExpressionsState = NIL;
 	/* predicate will likely be null, but may as well copy it */
-	newind->il_info->ii_Predicate = (List *)
+	newind->il_info->ii_Predicate =
 		copyObject(indexInfo->ii_Predicate);
 	newind->il_info->ii_PredicateState = NULL;
 	/* no exclusion constraints at bootstrap time, so no need to copy */

src/backend/commands/copy.c

@@ -1470,7 +1470,7 @@ BeginCopy(ParseState *pstate,
 		 * function and is executed repeatedly.  (See also the same hack in
 		 * DECLARE CURSOR and PREPARE.)  XXX FIXME someday.
 		 */
-		rewritten = pg_analyze_and_rewrite((RawStmt *) copyObject(raw_query),
+		rewritten = pg_analyze_and_rewrite(copyObject(raw_query),
 										   pstate->p_sourcetext, NULL, 0);
 
 		/* check that we got back something we can work with */

src/backend/commands/createas.c

@@ -315,7 +315,7 @@ ExecCreateTableAs(CreateTableAsStmt *stmt, const char *queryString,
 		 * and is executed repeatedly.  (See also the same hack in EXPLAIN and
 		 * PREPARE.)
 		 */
-		rewritten = QueryRewrite((Query *) copyObject(query));
+		rewritten = QueryRewrite(copyObject(query));
 
 		/* SELECT should never rewrite to more or less than one SELECT query */
 		if (list_length(rewritten) != 1)

src/backend/commands/event_trigger.c

@@ -1869,7 +1869,7 @@ EventTriggerCollectAlterOpFam(AlterOpFamilyStmt *stmt, Oid opfamoid,
 					 OperatorFamilyRelationId, opfamoid);
 	command->d.opfam.operators = operators;
 	command->d.opfam.procedures = procedures;
-	command->parsetree = copyObject(stmt);
+	command->parsetree = (Node *) copyObject(stmt);
 
 	currentEventTriggerState->commandList =
 		lappend(currentEventTriggerState->commandList, command);
@@ -1902,7 +1902,7 @@ EventTriggerCollectCreateOpClass(CreateOpClassStmt *stmt, Oid opcoid,
 					 OperatorClassRelationId, opcoid);
 	command->d.createopc.operators = operators;
 	command->d.createopc.procedures = procedures;
-	command->parsetree = copyObject(stmt);
+	command->parsetree = (Node *) copyObject(stmt);
 
 	currentEventTriggerState->commandList =
 		lappend(currentEventTriggerState->commandList, command);
@@ -1937,7 +1937,7 @@ EventTriggerCollectAlterTSConfig(AlterTSConfigurationStmt *stmt, Oid cfgId,
 	command->d.atscfg.dictIds = palloc(sizeof(Oid) * ndicts);
 	memcpy(command->d.atscfg.dictIds, dictIds, sizeof(Oid) * ndicts);
 	command->d.atscfg.ndicts = ndicts;
-	command->parsetree = copyObject(stmt);
+	command->parsetree = (Node *) copyObject(stmt);
 
 	currentEventTriggerState->commandList =
 		lappend(currentEventTriggerState->commandList, command);
@@ -1967,7 +1967,7 @@ EventTriggerCollectAlterDefPrivs(AlterDefaultPrivilegesStmt *stmt)
 	command->type = SCT_AlterDefaultPrivileges;
 	command->d.defprivs.objtype = stmt->action->objtype;
 	command->in_extension = creating_extension;
-	command->parsetree = copyObject(stmt);
+	command->parsetree = (Node *) copyObject(stmt);
 
 	currentEventTriggerState->commandList =
 		lappend(currentEventTriggerState->commandList, command);

src/backend/commands/prepare.c

@@ -352,7 +352,7 @@ EvaluateParams(PreparedStatement *pstmt, List *params,
 	 * We have to run parse analysis for the expressions.  Since the parser is
 	 * not cool about scribbling on its input, copy first.
 	 */
-	params = (List *) copyObject(params);
+	params = copyObject(params);
 
 	pstate = make_parsestate(NULL);
 	pstate->p_sourcetext = queryString;
@@ -554,7 +554,7 @@ FetchPreparedStatementTargetList(PreparedStatement *stmt)
 	tlist = CachedPlanGetTargetList(stmt->plansource);
 
 	/* Copy into caller's context in case plan gets invalidated */
-	return (List *) copyObject(tlist);
+	return copyObject(tlist);
 }
 
 /*

src/backend/commands/view.c

@@ -373,7 +373,7 @@ UpdateRangeTableOfViewParse(Oid viewOid, Query *viewParse)
 	 * Var node twice.  copyObject will expand any multiply-referenced subtree
 	 * into multiple copies.
 	 */
-	viewParse = (Query *) copyObject(viewParse);
+	viewParse = copyObject(viewParse);
 
 	/* Create a dummy ParseState for addRangeTableEntryForRelation */
 	pstate = make_parsestate(NULL);

src/backend/nodes/copyfuncs.c

@@ -43,7 +43,7 @@
 
 /* Copy a field that is a pointer to some kind of Node or Node tree */
 #define COPY_NODE_FIELD(fldname) \
-	(newnode->fldname = copyObject(from->fldname))
+	(newnode->fldname = copyObjectImpl(from->fldname))
 
 /* Copy a field that is a pointer to a Bitmapset */
 #define COPY_BITMAPSET_FIELD(fldname) \
@@ -4507,7 +4507,7 @@ _copyDropSubscriptionStmt(const DropSubscriptionStmt *from)
  */
 #define COPY_NODE_CELL(new, old)					\
 	(new) = (ListCell *) palloc(sizeof(ListCell));	\
-	lfirst(new) = copyObject(lfirst(old));
+	lfirst(new) = copyObjectImpl(lfirst(old));
 
 static List *
 _copyList(const List *from)
@@ -4610,13 +4610,13 @@ _copyForeignKeyCacheInfo(const ForeignKeyCacheInfo *from)
 
 
 /*
- * copyObject
+ * copyObjectImpl -- implementation of copyObject(); see nodes/nodes.h
  *
  * Create a copy of a Node tree or list.  This is a "deep" copy: all
  * substructure is copied too, recursively.
  */
 void *
-copyObject(const void *from)
+copyObjectImpl(const void *from)
 {
 	void	   *retval;
 

src/backend/optimizer/path/indxpath.c

@@ -4004,9 +4004,9 @@ adjust_rowcompare_for_index(RowCompareExpr *clause,
 									   matching_cols);
 		rc->inputcollids = list_truncate(list_copy(clause->inputcollids),
 										 matching_cols);
-		rc->largs = list_truncate((List *) copyObject(clause->largs),
+		rc->largs = list_truncate(copyObject(clause->largs),
 								  matching_cols);
-		rc->rargs = list_truncate((List *) copyObject(clause->rargs),
+		rc->rargs = list_truncate(copyObject(clause->rargs),
 								  matching_cols);
 		return (Expr *) rc;
 	}

src/backend/optimizer/plan/createplan.c

@@ -1275,7 +1275,7 @@ create_unique_plan(PlannerInfo *root, UniquePath *best_path, int flags)
 
 	foreach(l, uniq_exprs)
 	{
-		Node	   *uniqexpr = lfirst(l);
+		Expr	   *uniqexpr = lfirst(l);
 		TargetEntry *tle;
 
 		tle = tlist_member(uniqexpr, newtlist);
@@ -1318,7 +1318,7 @@ create_unique_plan(PlannerInfo *root, UniquePath *best_path, int flags)
 	groupColPos = 0;
 	foreach(l, uniq_exprs)
 	{
-		Node	   *uniqexpr = lfirst(l);
+		Expr	   *uniqexpr = lfirst(l);
 		TargetEntry *tle;
 
 		tle = tlist_member(uniqexpr, newtlist);
@@ -4318,7 +4318,7 @@ process_subquery_nestloop_params(PlannerInfo *root, List *subplan_params)
 				/* No, so add it */
 				nlp = makeNode(NestLoopParam);
 				nlp->paramno = pitem->paramId;
-				nlp->paramval = copyObject(phv);
+				nlp->paramval = (Var *) copyObject(phv);
 				root->curOuterParams = lappend(root->curOuterParams, nlp);
 			}
 		}

src/backend/optimizer/plan/initsplan.c

@@ -2306,8 +2306,8 @@ process_implied_equality(PlannerInfo *root,
 	clause = make_opclause(opno,
 						   BOOLOID,		/* opresulttype */
 						   false,		/* opretset */
-						   (Expr *) copyObject(item1),
-						   (Expr *) copyObject(item2),
+						   copyObject(item1),
+						   copyObject(item2),
 						   InvalidOid,
 						   collation);
 
@@ -2369,8 +2369,8 @@ build_implied_join_equality(Oid opno,
 	clause = make_opclause(opno,
 						   BOOLOID,		/* opresulttype */
 						   false,		/* opretset */
-						   (Expr *) copyObject(item1),
-						   (Expr *) copyObject(item2),
+						   copyObject(item1),
+						   copyObject(item2),
 						   InvalidOid,
 						   collation);
 

src/backend/optimizer/plan/planagg.c

@@ -369,11 +369,11 @@ build_minmax_path(PlannerInfo *root, MinMaxAggInfo *mminfo,
 	subroot->outer_params = NULL;
 	subroot->init_plans = NIL;
 
-	subroot->parse = parse = (Query *) copyObject(root->parse);
+	subroot->parse = parse = copyObject(root->parse);
 	IncrementVarSublevelsUp((Node *) parse, 1, 1);
 
 	/* append_rel_list might contain outer Vars? */
-	subroot->append_rel_list = (List *) copyObject(root->append_rel_list);
+	subroot->append_rel_list = copyObject(root->append_rel_list);
 	IncrementVarSublevelsUp((Node *) subroot->append_rel_list, 1, 1);
 	/* There shouldn't be any OJ info to translate, as yet */
 	Assert(subroot->join_info_list == NIL);

src/backend/optimizer/plan/planner.c

@@ -1157,7 +1157,7 @@ inheritance_planner(PlannerInfo *root)
 		 * executor doesn't need to see the modified copies --- we can just
 		 * pass it the original rowMarks list.)
 		 */
-		subroot->rowMarks = (List *) copyObject(root->rowMarks);
+		subroot->rowMarks = copyObject(root->rowMarks);
 
 		/*
 		 * The append_rel_list likewise might contain references to subquery
@@ -1179,7 +1179,7 @@ inheritance_planner(PlannerInfo *root)
 				AppendRelInfo *appinfo2 = (AppendRelInfo *) lfirst(lc2);
 
 				if (bms_is_member(appinfo2->child_relid, modifiableARIindexes))
-					appinfo2 = (AppendRelInfo *) copyObject(appinfo2);
+					appinfo2 = copyObject(appinfo2);
 
 				subroot->append_rel_list = lappend(subroot->append_rel_list,
 												   appinfo2);