test: add drop user case

zetasql/parser/ast_node_kind.h

@@ -265,6 +265,7 @@ enum ASTNodeKind {
   AST_START_BATCH_STATEMENT,
   AST_STATEMENT_LIST,
   AST_STRING_LITERAL,
+  AST_STRING_LITERAL_LIST,
   AST_STRUCT_COLUMN_FIELD,
   AST_STRUCT_COLUMN_SCHEMA,
   AST_STRUCT_CONSTRUCTOR_ARG,

zetasql/parser/bison_parser.y

@@ -1110,6 +1110,7 @@ using zetasql::ASTDropStatement;
 %type <node> variable_declaration
 %type <node> opt_default_expression
 %type <node> identifier_list
+%type <node> string_literal_list
 %type <node> path_expression_list
 %type <node> path_expression_list_with_opt_parens
 %type <node> set_statement
@@ -8518,7 +8519,7 @@ drop_statement:
         drop_row_access_policy->set_is_if_exists($5);
         $$ = drop_row_access_policy;
       }
-    | "DROP" "USER" opt_if_exists string_literal
+    | "DROP" "USER" opt_if_exists string_literal_list
       {
         auto* drop = MAKE_NODE(ASTDropUserStatement, @$, {$4});
         drop->set_is_if_exists($3);
@@ -8871,6 +8872,17 @@ identifier_list:
     }
     ;
 
+string_literal_list:
+    string_literal
+    {
+      $$ = MAKE_NODE(ASTStringLiteralList, @$, {$1});
+    }
+    | string_literal_list "," string_literal
+    {
+      $$ = WithEndLocation(WithExtraChildren($1, {$3}), @$);
+    }
+    ;
+
 variable_declaration:
     "DECLARE" identifier_list type opt_default_expression
     {

zetasql/parser/parse_tree.cc

@@ -303,6 +303,7 @@ static absl::flat_hash_map<ASTNodeKind, std::string> CreateNodeNamesMap() {
   map[AST_START_BATCH_STATEMENT] = "StartBatchStatement";
   map[AST_STATEMENT_LIST] = "StatementList";
   map[AST_STRING_LITERAL] = "StringLiteral";
+  map[AST_STRING_LITERAL_LIST] = "StringLiteralList";
   map[AST_STRUCT_COLUMN_FIELD] = "StructColumnField";
   map[AST_STRUCT_COLUMN_SCHEMA] = "StructColumnSchema";
   map[AST_STRUCT_CONSTRUCTOR_ARG] = "StructConstructorArg";

zetasql/parser/parse_tree_manual.h

@@ -4658,15 +4658,15 @@ class ASTDropUserStatement final : public ASTStatement {
       NonRecursiveParseTreeVisitor* visitor) const override;
   bool is_if_exists() const { return is_if_exists_; }
   void set_is_if_exists(bool value) { is_if_exists_ = value; }
-  const ASTStringLiteral* user_name() const { return user_name_; }
+  const ASTStringLiteralList* user_name_list() const { return user_name_list_; }
 
  private:
   void InitFields() final {
     FieldLoader fl(this);
-    fl.AddRequired(&user_name_);
+    fl.AddRequired(&user_name_list_);
   }
 
-  const ASTStringLiteral* user_name_ = nullptr;
+  const ASTStringLiteralList* user_name_list_ = nullptr;
   bool is_if_exists_ = false;
 };
 
@@ -8149,6 +8149,28 @@ class ASTIdentifierList final : public ASTNode {
   absl::Span<const ASTIdentifier* const> identifier_list_;
 };
 
+class ASTStringLiteralList final : public ASTNode {
+ public:
+  static constexpr ASTNodeKind kConcreteNodeKind = AST_STRING_LITERAL_LIST;
+
+  ASTStringLiteralList() : ASTNode(kConcreteNodeKind) {}
+  void Accept(ParseTreeVisitor* visitor, void* data) const override;
+  zetasql_base::StatusOr<VisitResult> Accept(
+      NonRecursiveParseTreeVisitor* visitor) const override;
+
+  // Guaranteed by the parser to never be empty.
+  absl::Span<const ASTStringLiteral* const> string_literal_list() const {
+    return string_literal_list_;
+  }
+
+ private:
+  void InitFields() final {
+    FieldLoader fl(this);
+    fl.AddRestAsRepeated(&string_literal_list_);
+  }
+  absl::Span<const ASTStringLiteral* const> string_literal_list_;
+};
+
 class ASTVariableDeclaration final : public ASTScriptStatement {
  public:
   static constexpr ASTNodeKind kConcreteNodeKind = AST_VARIABLE_DECLARATION;

zetasql/parser/testdata/drop_user.test

@@ -1,8 +1,28 @@
 drop user 'root';
 --
 DropUserStatement [0-16]
-  StringLiteral('root') [10-16]
+  StringLiteralList [10-16]
+    StringLiteral('root') [10-16]
 --
 DROP USER 'root'
 ==
 
+drop user 'user1', 'user2';
+--
+DropUserStatement [0-26]
+  StringLiteralList [10-26]
+    StringLiteral('user1') [10-17]
+    StringLiteral('user2') [19-26]
+--
+DROP USER 'user1', 'user2'
+==
+
+drop user if exists 'user1', 'user2';
+--
+DropUserStatement [0-36]
+  StringLiteralList [20-36]
+    StringLiteral('user1') [20-27]
+    StringLiteral('user2') [29-36]
+--
+DROP USER IF EXISTS 'user1', 'user2'
+==

zetasql/parser/unparser.cc

@@ -3100,7 +3100,7 @@ void Unparser::visitASTDropUserStatement(const ASTDropUserStatement* node,
   print("DROP");
   print("USER");
   if (node->is_if_exists()) print("IF EXISTS");
-  node->user_name()->Accept(this, data);
+  node->user_name_list()->Accept(this, data);
 }
 
 void Unparser::visitASTCreateUserStatement(const ASTCreateUserStatement* node,
@@ -3289,6 +3289,11 @@ void Unparser::visitASTIdentifierList(const ASTIdentifierList* node,
   UnparseVectorWithSeparator(node->identifier_list(), data, ", ");
 }
 
+void Unparser::visitASTStringLiteralList(const ASTStringLiteralList* node,
+                                      void* data) {
+  UnparseVectorWithSeparator(node->string_literal_list(), data, ", ");
+}
+
 void Unparser::visitASTVariableDeclaration(const ASTVariableDeclaration* node,
                                            void* data) {
   print("DECLARE");

zetasql/parser/unparser.h

@@ -609,6 +609,8 @@ class Unparser : public ParseTreeVisitor {
   void visitASTBeginEndBlock(const ASTBeginEndBlock* node, void* data) override;
   void visitASTIdentifierList(const ASTIdentifierList* node,
                               void* data) override;
+  void visitASTStringLiteralList(const ASTStringLiteralList* node,
+                              void* data) override;
   void visitASTVariableDeclaration(const ASTVariableDeclaration* node,
                                    void* data) override;
   void visitASTParameterAssignment(const ASTParameterAssignment* node,