sql: disallow star expressions in UDF bodies

This commit disallows star expressions in UDF bodies (see the release
note below). It also fixes an error message returned when trying to
create a view that references non-existent columns that incorrectly
mentioned star expressions.

Fixes cockroachdb#86070

Release note (sql change): Star expressions, e.g., `SELECT * FROM ...`
are no longer allowed in statements in user-defined functions. They were
allowed in early betas of v22.2 from v22.2.0-beta.1 to v22.2.0-beta.4,
but have been disallowed because they do not behave correctly.
Issue cockroachdb#90080 tracks re-enabling star expressions in UDFs.

pkg/sql/logictest/testdata/logic_test/udf

@@ -49,8 +49,26 @@ CREATE FUNCTION c(i INT, j INT) RETURNS INT LANGUAGE SQL AS 'SELECT i - j'
 statement error column \"j\" does not exist
 CREATE FUNCTION err(i INT) RETURNS INT LANGUAGE SQL AS 'SELECT j'
 
-statement error column \"j\" does not exist
-CREATE FUNCTION err(i INT) RETURNS INT LANGUAGE SQL AS 'SELECT * FROM ab WHERE a = j'
+statement error pgcode 42703 column \"j\" does not exist
+CREATE FUNCTION err(i INT) RETURNS INT LANGUAGE SQL AS 'SELECT a FROM ab WHERE a = j'
+
+statement error pgcode 0A000 functions do not currently support \* expressions
+CREATE FUNCTION err(i INT) RETURNS ab LANGUAGE SQL AS 'SELECT * FROM ab'
+
+statement error pgcode 0A000 functions do not currently support \* expressions
+CREATE FUNCTION err(i INT) RETURNS ab LANGUAGE SQL AS 'SELECT ab.* FROM ab'
+
+statement error pgcode 0A000 functions do not currently support \* expressions
+CREATE FUNCTION err(i INT) RETURNS ab LANGUAGE SQL AS $$
+  SELECT 1;
+  SELECT * FROM ab;
+$$
+
+statement error pgcode 0A000 functions do not currently support \* expressions
+CREATE FUNCTION err(i INT) RETURNS INT LANGUAGE SQL AS $$
+  SELECT * FROM ab;
+  SELECT 1;
+$$
 
 statement ok
 CREATE FUNCTION d(i INT2) RETURNS INT4 LANGUAGE SQL AS 'SELECT i'
@@ -2403,15 +2421,16 @@ SELECT imp(), (1,2,'a')::imp = imp(), pg_typeof(imp())
 ----
 (1,2,a)  true  imp
 
-statement ok
-CREATE FUNCTION imp_star() RETURNS imp LANGUAGE SQL AS $$
-  SELECT * FROM imp
-$$
-
-query TBT
-SELECT imp_star(), (1,2,'a')::imp = imp_star(), pg_typeof(imp_star())
-----
-(1,2,a)  true  imp
+# TODO(#90080): Allow star expressions in UDFs.
+# statement ok
+# CREATE FUNCTION imp_star() RETURNS imp LANGUAGE SQL AS $$
+#   SELECT * FROM imp
+# $$
+#
+# query TBT
+# SELECT imp_star(), (1,2,'a')::imp = imp_star(), pg_typeof(imp_star())
+# ----
+# (1,2,a)  true  imp
 
 statement ok
 INSERT INTO imp VALUES (100, 200, 'z')

pkg/sql/logictest/testdata/logic_test/views

@@ -43,6 +43,12 @@ CREATE VIEW v6 (x, y) AS SELECT a, b FROM v1
 statement ok
 CREATE VIEW v7 (x, y) AS SELECT a, b FROM v1 ORDER BY a DESC LIMIT 2
 
+statement error pgcode 42703 column \"j\" does not exist
+CREATE VIEW err AS SELECT j FROM t
+
+statement error pgcode 42703 column \"j\" does not exist
+CREATE VIEW err AS SELECT a FROM t WHERE a = j
+
 query II colnames,rowsort
 SELECT * FROM v1
 ----
@@ -1492,4 +1498,3 @@ SELECT * FROM v;
 
 statement ok
 SET DATABASE = test;
-

pkg/sql/opt/optbuilder/project.go

@@ -196,9 +196,10 @@ func (b *Builder) resolveColRef(e tree.Expr, inScope *scope) tree.TypedExpr {
 		if resolveErr != nil {
 			// It may be a reference to a table, e.g. SELECT tbl FROM tbl.
 			// Attempt to resolve as a TupleStar. We do not attempt to resolve
-			// as a TupleStar if we are inside a view definition because views
-			// do not support * expressions.
-			if !b.insideViewDef && sqlerrors.IsUndefinedColumnError(resolveErr) {
+			// as a TupleStar if we are inside a view or function definition
+			// because views and functions do not support * expressions.
+			if !b.insideViewDef && !b.insideFuncDef &&
+				sqlerrors.IsUndefinedColumnError(resolveErr) {
 				return func() tree.TypedExpr {
 					defer wrapColTupleStarPanic(resolveErr)
 					return inScope.resolveType(columnNameAsTupleStar(colName), types.Any)

pkg/sql/opt/optbuilder/scope.go

@@ -1025,7 +1025,12 @@ func (s *scope) VisitPre(expr tree.Expr) (recurse bool, newExpr tree.Expr) {
 	case *tree.ColumnItem:
 		colI, resolveErr := colinfo.ResolveColumnItem(s.builder.ctx, s, t)
 		if resolveErr != nil {
-			if sqlerrors.IsUndefinedColumnError(resolveErr) {
+			// It may be a reference to a table, e.g. SELECT tbl FROM tbl.
+			// Attempt to resolve as a TupleStar. We do not attempt to resolve
+			// as a TupleStar if we are inside a view or function definition
+			// because views and functions do not support * expressions.
+			if !s.builder.insideViewDef && !s.builder.insideFuncDef &&
+				sqlerrors.IsUndefinedColumnError(resolveErr) {
 				// Attempt to resolve as columnname.*, which allows items
 				// such as SELECT row_to_json(tbl_name) FROM tbl_name to work.
 				return func() (bool, tree.Expr) {

pkg/sql/opt/optbuilder/testdata/create_function

@@ -110,7 +110,7 @@ create-function
 build
 CREATE FUNCTION f() RETURNS INT LANGUAGE SQL AS $$ SELECT * FROM ab $$
 ----
-error (42P13): return type mismatch in function declared to return int
+error (0A000): unimplemented: functions do not currently support * expressions
 
 build
 CREATE FUNCTION f() RETURNS INT LANGUAGE SQL BEGIN ATOMIC SELECT 1; END;

pkg/sql/opt/optbuilder/util.go

@@ -64,6 +64,9 @@ func (b *Builder) expandStar(
 	if b.insideViewDef {
 		panic(unimplemented.NewWithIssue(10028, "views do not currently support * expressions"))
 	}
+	if b.insideFuncDef {
+		panic(unimplemented.NewWithIssue(90080, "functions do not currently support * expressions"))
+	}
 	switch t := expr.(type) {
 	case *tree.TupleStar:
 		texpr := inScope.resolveType(t.Expr, types.Any)