Fix: Snowflake ALTER SESSION cannot be followed by other statements.

Fixes apache#1775.

Currently parse_session_options does not check for semicolons, which
makes it impossible to parse multiple statements, where a statement
comes after ALTER SESSION.

Furthermore, it seems we should not advance the parser onto the
semicolon as it is otherwise skipped in the next loop iteration
of parse_statements() where the parser advances to the next token,
which would then result in "Expected end of statement".

Author: Roman Borschel

src/dialect/snowflake.rs

@@ -1013,10 +1013,15 @@ fn parse_session_options(
     let mut options: Vec<KeyValueOption> = Vec::new();
     let empty = String::new;
     loop {
-        match parser.next_token().token {
-            Token::SemiColon => break,
-            Token::Comma => continue,
+        let next_token = parser.peek_token();
+        match next_token.token {
+            Token::SemiColon | Token::EOF => break,
+            Token::Comma => {
+                parser.advance_token();
+                continue;
+            }
             Token::Word(key) => {
+                parser.advance_token();
                 if set {
                     let option = parse_option(parser, key)?;
                     options.push(option);
@@ -1028,13 +1033,8 @@ fn parse_session_options(
                     });
                 }
             }
-            t => {
-                println!("> NEXT TOKEN {:?}", t);
-                println!("> PEEK TOKEN {:?}", parser.peek_token().token);
-                if parser.peek_token().token == Token::EOF {
-                    break;
-                }
-                return parser.expected("another option", parser.peek_token());
+            _ => {
+                return parser.expected("another option or end of statement", next_token);
             }
         }
     }

tests/sqlparser_snowflake.rs

@@ -3507,7 +3507,12 @@ fn test_alter_session() {
 }
 
 #[test]
-fn voodoo() {
-    let res = snowflake().parse_sql_statements("ALTER SESSION SET QUERY_TAG='hello'; SELECT 42");
-    println!("{:?}", res);
+fn test_alter_session_followed_by_statement() {
+    let stmts = snowflake()
+        .parse_sql_statements("ALTER SESSION SET QUERY_TAG='hello'; SELECT 42")
+        .unwrap();
+    match stmts[..] {
+        [Statement::AlterSession { .. }, Statement::Query { .. }] => {}
+        _ => panic!("Unexpected statements: {:?}", stmts),
+    }
 }