Fix handling of GENERATED columns in CREATE TABLE LIKE INCLUDING DEFAULTS.

LIKE INCLUDING DEFAULTS tried to copy the attrdef expression without
copying the state of the attgenerated column.  This is in fact wrong,
because GENERATED and DEFAULT expressions are not the same kind of animal;
one can contain Vars and the other not.  We *must* copy attgenerated
when we're copying the attrdef expression.  Rearrange the if-tests
so that the expression is copied only when the correct one of
INCLUDING DEFAULTS and INCLUDING GENERATED has been specified.

Per private report from Manuel Rigger.

Tom Lane and Peter Eisentraut

src/backend/parser/parse_utilcmd.c

@@ -1023,11 +1023,13 @@ transformTableLikeClause(CreateStmtContext *cxt, TableLikeClause *table_like_cla
 		attmap[parent_attno - 1] = list_length(cxt->columns);
 
 		/*
-		 * Copy default, if present and the default has been requested
+		 * Copy default, if present and it should be copied.  We have separate
+		 * options for plain default expressions and GENERATED defaults.
 		 */
 		if (attribute->atthasdef &&
-			(table_like_clause->options & CREATE_TABLE_LIKE_DEFAULTS ||
-			 table_like_clause->options & CREATE_TABLE_LIKE_GENERATED))
+			(attribute->attgenerated ?
+			 (table_like_clause->options & CREATE_TABLE_LIKE_GENERATED) :
+			 (table_like_clause->options & CREATE_TABLE_LIKE_DEFAULTS)))
 		{
 			Node	   *this_default = NULL;
 			AttrDefault *attrdef;
@@ -1065,9 +1067,7 @@ transformTableLikeClause(CreateStmtContext *cxt, TableLikeClause *table_like_cla
 								   attributeName,
 								   RelationGetRelationName(relation))));
 
-			if (attribute->attgenerated &&
-				(table_like_clause->options & CREATE_TABLE_LIKE_GENERATED))
-				def->generated = attribute->attgenerated;
+			def->generated = attribute->attgenerated;
 		}
 
 		/*

src/test/regress/expected/create_table_like.out

@@ -159,6 +159,80 @@ SELECT * FROM test_like_gen_3;
 (1 row)
 
 DROP TABLE test_like_gen_1, test_like_gen_2, test_like_gen_3;
+CREATE TABLE test_like_4 (a int, b int DEFAULT 42, c int GENERATED ALWAYS AS (a * 2) STORED);
+\d test_like_4
+                          Table "public.test_like_4"
+ Column |  Type   | Collation | Nullable |              Default               
+--------+---------+-----------+----------+------------------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | 42
+ c      | integer |           |          | generated always as (a * 2) stored
+
+CREATE TABLE test_like_4a (LIKE test_like_4);
+CREATE TABLE test_like_4b (LIKE test_like_4 INCLUDING DEFAULTS);
+CREATE TABLE test_like_4c (LIKE test_like_4 INCLUDING GENERATED);
+CREATE TABLE test_like_4d (LIKE test_like_4 INCLUDING DEFAULTS INCLUDING GENERATED);
+\d test_like_4a
+            Table "public.test_like_4a"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+ b      | integer |           |          | 
+ c      | integer |           |          | 
+
+INSERT INTO test_like_4a VALUES(11);
+TABLE test_like_4a;
+ a  | b | c 
+----+---+---
+ 11 |   |  
+(1 row)
+
+\d test_like_4b
+            Table "public.test_like_4b"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+ b      | integer |           |          | 42
+ c      | integer |           |          | 
+
+INSERT INTO test_like_4b VALUES(11);
+TABLE test_like_4b;
+ a  | b  | c 
+----+----+---
+ 11 | 42 |  
+(1 row)
+
+\d test_like_4c
+                         Table "public.test_like_4c"
+ Column |  Type   | Collation | Nullable |              Default               
+--------+---------+-----------+----------+------------------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | 
+ c      | integer |           |          | generated always as (a * 2) stored
+
+INSERT INTO test_like_4c VALUES(11);
+TABLE test_like_4c;
+ a  | b | c  
+----+---+----
+ 11 |   | 22
+(1 row)
+
+\d test_like_4d
+                         Table "public.test_like_4d"
+ Column |  Type   | Collation | Nullable |              Default               
+--------+---------+-----------+----------+------------------------------------
+ a      | integer |           |          | 
+ b      | integer |           |          | 42
+ c      | integer |           |          | generated always as (a * 2) stored
+
+INSERT INTO test_like_4d VALUES(11);
+TABLE test_like_4d;
+ a  | b  | c  
+----+----+----
+ 11 | 42 | 22
+(1 row)
+
+DROP TABLE test_like_4, test_like_4a, test_like_4b, test_like_4c, test_like_4d;
 CREATE TABLE inhg (x text, LIKE inhx INCLUDING INDEXES, y text); /* copies indexes */
 INSERT INTO inhg VALUES (5, 10);
 INSERT INTO inhg VALUES (20, 10); -- should fail

src/test/regress/sql/create_table_like.sql

@@ -65,6 +65,26 @@ INSERT INTO test_like_gen_3 (a) VALUES (1);
 SELECT * FROM test_like_gen_3;
 DROP TABLE test_like_gen_1, test_like_gen_2, test_like_gen_3;
 
+CREATE TABLE test_like_4 (a int, b int DEFAULT 42, c int GENERATED ALWAYS AS (a * 2) STORED);
+\d test_like_4
+CREATE TABLE test_like_4a (LIKE test_like_4);
+CREATE TABLE test_like_4b (LIKE test_like_4 INCLUDING DEFAULTS);
+CREATE TABLE test_like_4c (LIKE test_like_4 INCLUDING GENERATED);
+CREATE TABLE test_like_4d (LIKE test_like_4 INCLUDING DEFAULTS INCLUDING GENERATED);
+\d test_like_4a
+INSERT INTO test_like_4a VALUES(11);
+TABLE test_like_4a;
+\d test_like_4b
+INSERT INTO test_like_4b VALUES(11);
+TABLE test_like_4b;
+\d test_like_4c
+INSERT INTO test_like_4c VALUES(11);
+TABLE test_like_4c;
+\d test_like_4d
+INSERT INTO test_like_4d VALUES(11);
+TABLE test_like_4d;
+DROP TABLE test_like_4, test_like_4a, test_like_4b, test_like_4c, test_like_4d;
+
 CREATE TABLE inhg (x text, LIKE inhx INCLUDING INDEXES, y text); /* copies indexes */
 INSERT INTO inhg VALUES (5, 10);
 INSERT INTO inhg VALUES (20, 10); -- should fail