Split CollateClause into separate raw and analyzed node types.

CollateClause is now used only in raw grammar output, and CollateExpr after
parse analysis.  This is for clarity and to avoid carrying collation names
in post-analysis parse trees: that's both wasteful and possibly misleading,
since the collation's name could be changed while the parsetree still
exists.

Also, clean up assorted infelicities and omissions in processing of the
node type.

1 files changed, 45 insertions, 15 deletions

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 7cbd0222cb2..ac0c53a7f32 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -226,6 +226,7 @@ static void get_coercion_expr(Node *arg, deparse_context *context,
 				  Node *parentNode);
 static void get_const_expr(Const *constval, deparse_context *context,
 			   int showtype);
+static void get_const_collation(Const *constval, deparse_context *context);
 static void simple_quote_literal(StringInfo buf, const char *val);
 static void get_sublink_expr(SubLink *sublink, deparse_context *context);
 static void get_from_clause(Query *query, const char *prefix,
@@ -5075,21 +5076,6 @@ get_rule_expr(Node *node, deparse_context *context,
 			}
 			break;
 
-		case T_CollateClause:
-			{
-				CollateClause *collate = (CollateClause *) node;
-				Node	   *arg = (Node *) collate->arg;
-
-				if (!PRETTY_PAREN(context))
-					appendStringInfoChar(buf, '(');
-				get_rule_expr_paren(arg, context, showimplicit, node);
-				appendStringInfo(buf, " COLLATE %s",
-								 generate_collation_name(collate->collOid));
-				if (!PRETTY_PAREN(context))
-					appendStringInfoChar(buf, ')');
-			}
-			break;
-
 		case T_CoerceViaIO:
 			{
 				CoerceViaIO *iocoerce = (CoerceViaIO *) node;
@@ -5152,6 +5138,21 @@ get_rule_expr(Node *node, deparse_context *context,
 			}
 			break;
 
+		case T_CollateExpr:
+			{
+				CollateExpr *collate = (CollateExpr *) node;
+				Node	   *arg = (Node *) collate->arg;
+
+				if (!PRETTY_PAREN(context))
+					appendStringInfoChar(buf, '(');
+				get_rule_expr_paren(arg, context, showimplicit, node);
+				appendStringInfo(buf, " COLLATE %s",
+								 generate_collation_name(collate->collOid));
+				if (!PRETTY_PAREN(context))
+					appendStringInfoChar(buf, ')');
+			}
+			break;
+
 		case T_CaseExpr:
 			{
 				CaseExpr   *caseexpr = (CaseExpr *) node;
@@ -5974,6 +5975,10 @@ get_coercion_expr(Node *arg, deparse_context *context,
  * showtype can be -1 to never show "::typename" decoration, or +1 to always
  * show it, or 0 to show it only if the constant wouldn't be assumed to be
  * the right type by default.
+ *
+ * If the Const's collation isn't default for its type, show that too.
+ * This can only happen in trees that have been through constant-folding.
+ * We assume we don't need to do this when showtype is -1.
  * ----------
  */
 static void
@@ -5994,9 +5999,12 @@ get_const_expr(Const *constval, deparse_context *context, int showtype)
 		 */
 		appendStringInfo(buf, "NULL");
 		if (showtype >= 0)
+		{
 			appendStringInfo(buf, "::%s",
 							 format_type_with_typemod(constval->consttype,
 													  constval->consttypmod));
+			get_const_collation(constval, context);
+		}
 		return;
 	}
 
@@ -6097,6 +6105,28 @@ get_const_expr(Const *constval, deparse_context *context, int showtype)
 		appendStringInfo(buf, "::%s",
 						 format_type_with_typemod(constval->consttype,
 												  constval->consttypmod));
+
+	get_const_collation(constval, context);
+}
+
+/*
+ * helper for get_const_expr: append COLLATE if needed
+ */
+static void
+get_const_collation(Const *constval, deparse_context *context)
+{
+	StringInfo	buf = context->buf;
+
+	if (OidIsValid(constval->constcollid))
+	{
+		Oid		typcollation = get_typcollation(constval->consttype);
+
+		if (constval->constcollid != typcollation)
+		{
+			appendStringInfo(buf, " COLLATE %s",
+							 generate_collation_name(constval->constcollid));
+		}
+	}
 }
 
 /*