l-wang · l-wang · Oct 14, 2022 · Apr 1, 2023 · Apr 1, 2023 · Apr 1, 2023
diff --git a/src/backend/executor/execExpr.c b/src/backend/executor/execExpr.c
@@ -3328,9 +3328,15 @@ ExecInitSubscriptingRef(ExprEvalStep *scratch, SubscriptingRef *sbsref,
 		{
 			sbsrefstate->upperprovided[i] = true;
 			/* Each subscript is evaluated into appropriate array entry */
-			ExecInitExprRec(e, state,
-							&sbsrefstate->upperindex[i],
-							&sbsrefstate->upperindexnull[i]);
+			if (IsA(e, String))
+			{
+				sbsrefstate->upperindex[i] = CStringGetTextDatum(strVal(e));
+				sbsrefstate->upperindexnull[i] = false;
+			}
+			else
+				ExecInitExprRec(e, state,
+								&sbsrefstate->upperindex[i],
+								&sbsrefstate->upperindexnull[i]);
 		}
 		i++;
 	}
@@ -3351,9 +3357,15 @@ ExecInitSubscriptingRef(ExprEvalStep *scratch, SubscriptingRef *sbsref,
 		{
 			sbsrefstate->lowerprovided[i] = true;
 			/* Each subscript is evaluated into appropriate array entry */
-			ExecInitExprRec(e, state,
-							&sbsrefstate->lowerindex[i],
-							&sbsrefstate->lowerindexnull[i]);
+			if (IsA(e, String))
+			{
+				sbsrefstate->lowerindex[i] = CStringGetTextDatum(strVal(e));
+				sbsrefstate->lowerindexnull[i] = false;
+			}
+			else
+				ExecInitExprRec(e, state,
+								&sbsrefstate->lowerindex[i],
+								&sbsrefstate->lowerindexnull[i]);
 		}
 		i++;
 	}

diff --git a/src/backend/nodes/nodeFuncs.c b/src/backend/nodes/nodeFuncs.c
@@ -2182,12 +2182,28 @@ expression_tree_walker_impl(Node *node,
 		case T_SubscriptingRef:
 			{
 				SubscriptingRef *sbsref = (SubscriptingRef *) node;
+				ListCell   *lc;
+
+				/*
+				 * Recurse directly for upper/lower container index lists,
+				 * skipping String subscripts used for dot notation.
+				 */
+				foreach(lc, sbsref->refupperindexpr)
+				{
+					Node	   *expr = lfirst(lc);
+
+					if (expr && !IsA(expr, String) && WALK(expr))
+						return true;
+				}
+
+				foreach(lc, sbsref->reflowerindexpr)
+				{
+					Node	   *expr = lfirst(lc);
+
+					if (expr && !IsA(expr, String) && WALK(expr))
+						return true;
+				}
 
-				/* recurse directly for upper/lower container index lists */
-				if (LIST_WALK(sbsref->refupperindexpr))
-					return true;
-				if (LIST_WALK(sbsref->reflowerindexpr))
-					return true;
 				/* walker must see the refexpr and refassgnexpr, however */
 				if (WALK(sbsref->refexpr))
 					return true;
@@ -3082,12 +3098,51 @@ expression_tree_mutator_impl(Node *node,
 			{
 				SubscriptingRef *sbsref = (SubscriptingRef *) node;
 				SubscriptingRef *newnode;
+				ListCell   *lc;
+				List	   *exprs = NIL;
 
 				FLATCOPY(newnode, sbsref, SubscriptingRef);
-				MUTATE(newnode->refupperindexpr, sbsref->refupperindexpr,
-					   List *);
-				MUTATE(newnode->reflowerindexpr, sbsref->reflowerindexpr,
-					   List *);
+
+				foreach(lc, sbsref->refupperindexpr)
+				{
+					Node	   *expr = lfirst(lc);
+
+					if (expr && IsA(expr, String))
+					{
+						String	   *str;
+
+						FLATCOPY(str, expr, String);
+						expr = (Node *) str;
+					}
+					else
+						expr = mutator(expr, context);
+
+					exprs = lappend(exprs, expr);
+				}
+
+				newnode->refupperindexpr = exprs;
+
+				exprs = NIL;
+
+				foreach(lc, sbsref->reflowerindexpr)
+				{
+					Node	   *expr = lfirst(lc);
+
+					if (expr && IsA(expr, String))
+					{
+						String	   *str;
+
+						FLATCOPY(str, expr, String);
+						expr = (Node *) str;
+					}
+					else
+						expr = mutator(expr, context);
+
+					exprs = lappend(exprs, expr);
+				}
+
+				newnode->reflowerindexpr = exprs;
+
 				MUTATE(newnode->refexpr, sbsref->refexpr,
 					   Expr *);
 				MUTATE(newnode->refassgnexpr, sbsref->refassgnexpr,

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
@@ -18968,6 +18968,7 @@ check_func_name(List *names, core_yyscan_t yyscanner)
 static List *
 check_indirection(List *indirection, core_yyscan_t yyscanner)
 {
+#if 0
 	ListCell   *l;
 
 	foreach(l, indirection)
@@ -18978,6 +18979,7 @@ check_indirection(List *indirection, core_yyscan_t yyscanner)
 				parser_yyerror("improper use of \"*\"");
 		}
 	}
+#endif
 	return indirection;
 }
 

diff --git a/src/backend/parser/parse_collate.c b/src/backend/parser/parse_collate.c
@@ -680,11 +680,25 @@ assign_collations_walker(Node *node, assign_collations_context *context)
 							 * contribute anything.)
 							 */
 							SubscriptingRef *sbsref = (SubscriptingRef *) node;
+							ListCell   *lc;
+
+							/* skip String subscripts used for dot notation */
+							foreach(lc, sbsref->refupperindexpr)
+							{
+								Node	   *expr = lfirst(lc);
+
+								if (expr && !IsA(expr, String))
+									assign_expr_collations(context->pstate, expr);
+							}
+
+							foreach(lc, sbsref->reflowerindexpr)
+							{
+								Node	   *expr = lfirst(lc);
+
+								if (expr && !IsA(expr, String))
+									assign_expr_collations(context->pstate, expr);
+							}
 
-							assign_expr_collations(context->pstate,
-												   (Node *) sbsref->refupperindexpr);
-							assign_expr_collations(context->pstate,
-												   (Node *) sbsref->reflowerindexpr);
 							(void) assign_collations_walker((Node *) sbsref->refexpr,
 															&loccontext);
 							(void) assign_collations_walker((Node *) sbsref->refassgnexpr,

diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
@@ -74,7 +74,6 @@ static Node *transformColumnRef(ParseState *pstate, ColumnRef *cref);
 static Node *transformWholeRowRef(ParseState *pstate,
 								  ParseNamespaceItem *nsitem,
 								  int sublevels_up, int location);
-static Node *transformIndirection(ParseState *pstate, A_Indirection *ind);
 static Node *transformTypeCast(ParseState *pstate, TypeCast *tc);
 static Node *transformCollateClause(ParseState *pstate, CollateClause *c);
 static Node *transformJsonObjectConstructor(ParseState *pstate,
@@ -158,7 +157,7 @@ transformExprRecurse(ParseState *pstate, Node *expr)
 			break;
 
 		case T_A_Indirection:
-			result = transformIndirection(pstate, (A_Indirection *) expr);
+			result = transformIndirection(pstate, (A_Indirection *) expr, NULL);
 			break;
 
 		case T_A_ArrayExpr:
@@ -432,8 +431,9 @@ unknown_attribute(ParseState *pstate, Node *relref, const char *attname,
 	}
 }
 
-static Node *
-transformIndirection(ParseState *pstate, A_Indirection *ind)
+Node *
+transformIndirection(ParseState *pstate, A_Indirection *ind,
+					 bool *trailing_star_expansion)
 {
 	Node	   *last_srf = pstate->p_last_srf;
 	Node	   *result = transformExprRecurse(pstate, ind->arg);
@@ -453,48 +453,77 @@ transformIndirection(ParseState *pstate, A_Indirection *ind)
 		if (IsA(n, A_Indices))
 			subscripts = lappend(subscripts, n);
 		else if (IsA(n, A_Star))
+			subscripts = lappend(subscripts, n);
+		else
 		{
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("row expansion via \"*\" is not supported here"),
-					 parser_errposition(pstate, location)));
+			Assert(IsA(n, String));
+			subscripts = lappend(subscripts, n);
 		}
-		else
+	}
+
+	/* process trailing subscripts, if any */
+	while (subscripts)
+	{
+		Node	   *newresult = (Node *)
+			transformContainerSubscripts(pstate,
+										 result,
+										 exprType(result),
+										 exprTypmod(result),
+										 &subscripts,
+										 false,
+										 true);
+
+		if (!newresult)
 		{
-			Node	   *newresult;
+			/* generic subscripting failed */
+			Node	   *n;
 
-			Assert(IsA(n, String));
+			Assert(subscripts);
 
-			/* process subscripts before this field selection */
-			if (subscripts)
-				result = (Node *) transformContainerSubscripts(pstate,
-															   result,
-															   exprType(result),
-															   exprTypmod(result),
-															   subscripts,
-															   false);
-			subscripts = NIL;
+			n = linitial(subscripts);
 
+			if (IsA(n, A_Star))
+			{
+				/* Success, if trailing star expansion is allowed */
+				if (trailing_star_expansion && list_length(subscripts) == 1)
+				{
+					*trailing_star_expansion = true;
+					return result;
+				}
+
+				ereport(ERROR,
+						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+						 errmsg("row expansion via \"*\" is not supported here"),
+						 parser_errposition(pstate, location)));
+			}
+			else if (!IsA(n, String))
+				ereport(ERROR,
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("cannot subscript type %s because it does not support subscripting",
+								format_type_be(exprType(result))),
+						 parser_errposition(pstate, exprLocation(result))));
+
+			/* try to find function for field selection */
 			newresult = ParseFuncOrColumn(pstate,
 										  list_make1(n),
 										  list_make1(result),
 										  last_srf,
 										  NULL,
 										  false,
 										  location);
-			if (newresult == NULL)
+
+			if (!newresult)
 				unknown_attribute(pstate, result, strVal(n), location);
-			result = newresult;
+
+			/* consume field select */
+			subscripts = list_delete_first(subscripts);
 		}
+
+		result = newresult;
 	}
-	/* process trailing subscripts, if any */
-	if (subscripts)
-		result = (Node *) transformContainerSubscripts(pstate,
-													   result,
-													   exprType(result),
-													   exprTypmod(result),
-													   subscripts,
-													   false);
+
+	if (trailing_star_expansion)
+		*trailing_star_expansion = false;
 
 	return result;
 }

diff --git a/src/backend/parser/parse_node.c b/src/backend/parser/parse_node.c
@@ -244,14 +244,16 @@ transformContainerSubscripts(ParseState *pstate,
 							 Node *containerBase,
 							 Oid containerType,
 							 int32 containerTypMod,
-							 List *indirection,
-							 bool isAssignment)
+							 List **indirection,
+							 bool isAssignment,
+							 bool noError)
 {
 	SubscriptingRef *sbsref;
 	const SubscriptRoutines *sbsroutines;
 	Oid			elementType;
 	bool		isSlice = false;
 	ListCell   *idx;
+	int			indirection_length = list_length(*indirection);
 
 	/*
 	 * Determine the actual container type, smashing any domain.  In the
@@ -267,11 +269,16 @@ transformContainerSubscripts(ParseState *pstate,
 	 */
 	sbsroutines = getSubscriptingRoutines(containerType, &elementType);
 	if (!sbsroutines)
+	{
+		if (noError)
+			return NULL;
+
 		ereport(ERROR,
 				(errcode(ERRCODE_DATATYPE_MISMATCH),
 				 errmsg("cannot subscript type %s because it does not support subscripting",
 						format_type_be(containerType)),
 				 parser_errposition(pstate, exprLocation(containerBase))));
+	}
 
 	/*
 	 * Detect whether any of the indirection items are slice specifiers.
@@ -280,11 +287,11 @@ transformContainerSubscripts(ParseState *pstate,
 	 * element.  If any of the items are slice specifiers (lower:upper), then
 	 * the subscript expression means a container slice operation.
 	 */
-	foreach(idx, indirection)
+	foreach(idx, *indirection)
 	{
-		A_Indices  *ai = lfirst_node(A_Indices, idx);
+		Node	   *ai = lfirst(idx);
 
-		if (ai->is_slice)
+		if (IsA(ai, A_Indices) && castNode(A_Indices, ai)->is_slice)
 		{
 			isSlice = true;
 			break;
@@ -312,6 +319,32 @@ transformContainerSubscripts(ParseState *pstate,
 	sbsroutines->transform(sbsref, indirection, pstate,
 						   isSlice, isAssignment);
 
+	/*
+	 * Error out, if datatyoe falied to consume any indirection elements.
+	 */
+	if (list_length(*indirection) == indirection_length)
+	{
+		Node	   *ind = linitial(*indirection);
+
+		if (noError)
+			return NULL;
+
+		if (IsA(ind, String))
+			ereport(ERROR,
+					(errcode(ERRCODE_DATATYPE_MISMATCH),
+					 errmsg("type %s does not support column notation",
+							format_type_be(containerType)),
+					 parser_errposition(pstate, exprLocation(containerBase))));
+		else if (IsA(ind, A_Indices))
+			ereport(ERROR,
+					(errcode(ERRCODE_DATATYPE_MISMATCH),
+					 errmsg("type %s does not support array subscripting",
+							format_type_be(containerType)),
+					 parser_errposition(pstate, exprLocation(containerBase))));
+		else
+			elog(ERROR, "invalid indirection operation: %d", nodeTag(ind));
+	}
+
 	/*
 	 * Verify we got a valid type (this defends, for example, against someone
 	 * using array_subscript_handler as typsubscript without setting typelem).