orm: allow use of mut db orm.Connection (#17439)

cmd/tools/vtest-self.v

@@ -128,6 +128,7 @@ const (
 		'vlib/orm/orm_last_id_test.v',
 		'vlib/orm/orm_string_interpolation_in_where_test.v',
 		'vlib/orm/orm_interface_test.v',
+		'vlib/orm/orm_mut_db_test.v',
 		'vlib/db/sqlite/sqlite_test.v',
 		'vlib/db/sqlite/sqlite_orm_test.v',
 		'vlib/db/sqlite/sqlite_vfs_lowlevel_test.v',
@@ -199,6 +200,7 @@ const (
 		'vlib/orm/orm_last_id_test.v',
 		'vlib/orm/orm_string_interpolation_in_where_test.v',
 		'vlib/orm/orm_interface_test.v',
+		'vlib/orm/orm_mut_db_test.v',
 		'vlib/v/tests/orm_sub_struct_test.v',
 		'vlib/v/tests/orm_sub_array_struct_test.v',
 		'vlib/v/tests/orm_joined_tables_select_test.v',

vlib/orm/orm_mut_db_test.v

@@ -0,0 +1,36 @@
+import db.sqlite
+
+struct User {
+	id   int    [primary; sql: serial]
+	name string
+}
+
+fn get_users(mut db sqlite.DB) []User {
+	return sql db {
+		select from User
+	}
+}
+
+fn test_orm_mut_db() {
+	mut db := sqlite.connect(':memory:') or { panic(err) }
+
+	sql db {
+		create table User
+	}
+
+	first_user := User{
+		name: 'first'
+	}
+	second_user := User{
+		name: 'second'
+	}
+
+	sql db {
+		insert first_user into User
+		insert second_user into User
+	}
+
+	users := get_users(mut db)
+
+	assert users.len == 2
+}

vlib/v/gen/c/sql.v

@@ -12,24 +12,12 @@ enum SqlExprSide {
 }
 
 fn (mut g Gen) sql_stmt(node ast.SqlStmt) {
-	conn := g.new_tmp_var()
-	g.writeln('')
-	g.writeln('// orm')
-	g.write('orm__Connection ${conn} = ')
+	connection_var_name := g.new_tmp_var()
 
-	db_expr_ctype_name := g.typ(node.db_expr_type)
-
-	if db_expr_ctype_name == 'orm__Connection' {
-		g.expr(node.db_expr)
-		g.writeln(';')
-	} else {
-		g.write('(orm__Connection){._${db_expr_ctype_name} = &')
-		g.expr(node.db_expr)
-		g.writeln(', ._typ = _orm__Connection_${db_expr_ctype_name}_index};')
-	}
+	g.write_orm_connection_init(connection_var_name, &node.db_expr)
 
 	for line in node.lines {
-		g.sql_stmt_line(line, conn, node.or_expr)
+		g.sql_stmt_line(line, connection_var_name, node.or_expr)
 	}
 }
 
@@ -539,25 +527,12 @@ fn (mut g Gen) sql_gen_where_data(where_expr ast.Expr) {
 
 fn (mut g Gen) sql_select_expr(node ast.SqlExpr) {
 	left := g.go_before_stmt(0)
-	conn := g.new_tmp_var()
+	connection_var_name := g.new_tmp_var()
 	g.writeln('')
-	g.writeln('// orm')
-	g.write('orm__Connection ${conn} = ')
-	db_expr_type := g.get_db_type(node.db_expr) or {
-		verror('sql orm error - unknown db type for ${node.db_expr}')
-	}
-	db_expr_ctype_name := g.typ(db_expr_type)
 
-	if db_expr_ctype_name == 'orm__Connection' {
-		g.expr(node.db_expr)
-		g.writeln(';')
-	} else {
-		g.write('(orm__Connection){._${db_expr_ctype_name} = &')
-		g.expr(node.db_expr)
-		g.writeln(', ._typ = _orm__Connection_${db_expr_ctype_name}_index};')
-	}
+	g.write_orm_connection_init(connection_var_name, &node.db_expr)
 
-	g.sql_select(node, conn, left, node.or_expr)
+	g.sql_select(node, connection_var_name, left, node.or_expr)
 }
 
 fn (mut g Gen) sql_select(node ast.SqlExpr, expr string, left string, or_expr ast.OrExpr) {
@@ -899,3 +874,24 @@ fn (mut g Gen) write_error_handling_for_orm_result(expr_pos &token.Pos, result_v
 
 	g.writeln('}')
 }
+
+fn (mut g Gen) write_orm_connection_init(connection_var_name string, db_expr &ast.Expr) {
+	db_expr_type := g.get_db_type(db_expr) or { verror('V ORM: unknown db type for ${db_expr}') }
+
+	mut db_ctype_name := g.typ(db_expr_type)
+	is_pointer := db_ctype_name.ends_with('*')
+	reference_sign := if is_pointer { '' } else { '&' }
+	db_ctype_name = db_ctype_name.trim_right('*')
+
+	g.writeln('// orm')
+	g.write('orm__Connection ${connection_var_name} = ')
+
+	if db_ctype_name == 'orm__Connection' {
+		g.expr(db_expr)
+		g.writeln(';')
+	} else {
+		g.write('(orm__Connection){._${db_ctype_name} = ${reference_sign}')
+		g.expr(db_expr)
+		g.writeln(', ._typ = _orm__Connection_${db_ctype_name}_index};')
+	}
+}