From 004025c3c4bfb3e9998e5c860700e357d70b41a4 Mon Sep 17 00:00:00 2001
From: Timothy Flynn <trflynn89@pm.me>
Date: Fri, 23 Apr 2021 14:45:56 -0400
Subject: LibSQL: Parse common-table-expressions with a nested SELECT statement

This also moves testing of common-table-expression to its own test case.
---
 Userland/Libraries/LibSQL/AST.h                    |   5 +-
 Userland/Libraries/LibSQL/Parser.cpp               |   4 +-
 .../LibSQL/Tests/TestSqlStatementParser.cpp        | 116 ++++++++++++---------
 3 files changed, 71 insertions(+), 54 deletions(-)

(limited to 'Userland/Libraries/LibSQL')

diff --git a/Userland/Libraries/LibSQL/AST.h b/Userland/Libraries/LibSQL/AST.h
index fe8ff4d443..1c7a90eb26 100644
--- a/Userland/Libraries/LibSQL/AST.h
+++ b/Userland/Libraries/LibSQL/AST.h
@@ -83,18 +83,21 @@ private:
 
 class CommonTableExpression : public ASTNode {
 public:
-    CommonTableExpression(String table_name, Vector<String> column_names)
+    CommonTableExpression(String table_name, Vector<String> column_names, NonnullRefPtr<Select> select_statement)
         : m_table_name(move(table_name))
         , m_column_names(move(column_names))
+        , m_select_statement(move(select_statement))
     {
     }
 
     const String& table_name() const { return m_table_name; }
     const Vector<String>& column_names() const { return m_column_names; }
+    const NonnullRefPtr<Select>& select_statement() const { return m_select_statement; }
 
 private:
     String m_table_name;
     Vector<String> m_column_names;
+    NonnullRefPtr<Select> m_select_statement;
 };
 
 class CommonTableExpressionList : public ASTNode {
diff --git a/Userland/Libraries/LibSQL/Parser.cpp b/Userland/Libraries/LibSQL/Parser.cpp
index d1a7afda43..cd9e46afdb 100644
--- a/Userland/Libraries/LibSQL/Parser.cpp
+++ b/Userland/Libraries/LibSQL/Parser.cpp
@@ -719,10 +719,10 @@ NonnullRefPtr<CommonTableExpression> Parser::parse_common_table_expression()
 
     consume(TokenType::As);
     consume(TokenType::ParenOpen);
-    // FIXME: Parse "select-stmt".
+    auto select_statement = parse_select_statement({});
     consume(TokenType::ParenClose);
 
-    return create_ast_node<CommonTableExpression>(move(table_name), move(column_names));
+    return create_ast_node<CommonTableExpression>(move(table_name), move(column_names), move(select_statement));
 }
 
 NonnullRefPtr<QualifiedTableName> Parser::parse_qualified_table_name()
diff --git a/Userland/Libraries/LibSQL/Tests/TestSqlStatementParser.cpp b/Userland/Libraries/LibSQL/Tests/TestSqlStatementParser.cpp
index 06b4b5f82d..946089a169 100644
--- a/Userland/Libraries/LibSQL/Tests/TestSqlStatementParser.cpp
+++ b/Userland/Libraries/LibSQL/Tests/TestSqlStatementParser.cpp
@@ -56,7 +56,6 @@ TEST_CASE(create_table)
     EXPECT(parse("CREATE TABLE test ( column1 varchar(.abc) )").is_error());
     EXPECT(parse("CREATE TABLE test ( column1 varchar(0x) )").is_error());
     EXPECT(parse("CREATE TABLE test ( column1 varchar(0xzzz) )").is_error());
-    EXPECT(parse("WITH table AS () CREATE TABLE test ( column1 );").is_error());
     EXPECT(parse("CREATE TABLE test ( column1 int ) AS SELECT * FROM table;").is_error());
     EXPECT(parse("CREATE TABLE test AS SELECT * FROM table ( column1 int ) ;").is_error());
 
@@ -132,7 +131,6 @@ TEST_CASE(drop_table)
     EXPECT(parse("DROP TABLE").is_error());
     EXPECT(parse("DROP TABLE test").is_error());
     EXPECT(parse("DROP TABLE IF test;").is_error());
-    EXPECT(parse("WITH table AS () DROP TABLE test;").is_error());
 
     auto validate = [](StringView sql, StringView expected_schema, StringView expected_table, bool expected_is_error_if_table_does_not_exist = true) {
         auto result = parse(sql);
@@ -164,23 +162,8 @@ TEST_CASE(delete_)
     EXPECT(parse("DELETE FROM table WHERE 15 RETURNING column").is_error());
     EXPECT(parse("DELETE FROM table WHERE 15 RETURNING column AS;").is_error());
     EXPECT(parse("DELETE FROM table WHERE (');").is_error());
-    EXPECT(parse("WITH DELETE FROM table;").is_error());
-    EXPECT(parse("WITH table DELETE FROM table;").is_error());
-    EXPECT(parse("WITH table AS DELETE FROM table;").is_error());
-    EXPECT(parse("WITH RECURSIVE table DELETE FROM table;").is_error());
-    EXPECT(parse("WITH RECURSIVE table AS DELETE FROM table;").is_error());
-
-    struct SelectedTableList {
-        struct SelectedTable {
-            StringView table_name {};
-            Vector<StringView> column_names {};
-        };
-
-        bool recursive { false };
-        Vector<SelectedTable> selected_tables {};
-    };
 
-    auto validate = [](StringView sql, SelectedTableList expected_selected_tables, StringView expected_schema, StringView expected_table, StringView expected_alias, bool expect_where_clause, bool expect_returning_clause, Vector<StringView> expected_returned_column_aliases) {
+    auto validate = [](StringView sql, StringView expected_schema, StringView expected_table, StringView expected_alias, bool expect_where_clause, bool expect_returning_clause, Vector<StringView> expected_returned_column_aliases) {
         auto result = parse(sql);
         EXPECT(!result.is_error());
 
@@ -189,25 +172,6 @@ TEST_CASE(delete_)
 
         const auto& delete_ = static_cast<const SQL::Delete&>(*statement);
 
-        const auto& common_table_expression_list = delete_.common_table_expression_list();
-        EXPECT_EQ(common_table_expression_list.is_null(), expected_selected_tables.selected_tables.is_empty());
-        if (common_table_expression_list) {
-            EXPECT_EQ(common_table_expression_list->recursive(), expected_selected_tables.recursive);
-
-            const auto& common_table_expressions = common_table_expression_list->common_table_expressions();
-            EXPECT_EQ(common_table_expressions.size(), expected_selected_tables.selected_tables.size());
-
-            for (size_t i = 0; i < common_table_expressions.size(); ++i) {
-                const auto& common_table_expression = common_table_expressions[i];
-                const auto& expected_common_table_expression = expected_selected_tables.selected_tables[i];
-                EXPECT_EQ(common_table_expression.table_name(), expected_common_table_expression.table_name);
-                EXPECT_EQ(common_table_expression.column_names().size(), expected_common_table_expression.column_names.size());
-
-                for (size_t j = 0; j < common_table_expression.column_names().size(); ++j)
-                    EXPECT_EQ(common_table_expression.column_names()[j], expected_common_table_expression.column_names[j]);
-            }
-        }
-
         const auto& qualified_table_name = delete_.qualified_table_name();
         EXPECT_EQ(qualified_table_name->schema_name(), expected_schema);
         EXPECT_EQ(qualified_table_name->table_name(), expected_table);
@@ -233,20 +197,14 @@ TEST_CASE(delete_)
         }
     };
 
-    validate("DELETE FROM table;", {}, {}, "table", {}, false, false, {});
-    validate("DELETE FROM schema.table;", {}, "schema", "table", {}, false, false, {});
-    validate("DELETE FROM schema.table AS alias;", {}, "schema", "table", "alias", false, false, {});
-    validate("DELETE FROM table WHERE (1 == 1);", {}, {}, "table", {}, true, false, {});
-    validate("DELETE FROM table RETURNING *;", {}, {}, "table", {}, false, true, {});
-    validate("DELETE FROM table RETURNING column;", {}, {}, "table", {}, false, true, { {} });
-    validate("DELETE FROM table RETURNING column AS alias;", {}, {}, "table", {}, false, true, { "alias" });
-    validate("DELETE FROM table RETURNING column1 AS alias1, column2 AS alias2;", {}, {}, "table", {}, false, true, { "alias1", "alias2" });
-
-    // FIXME: When parsing of SELECT statements are supported, the common-table-expressions below will become invalid due to the empty "AS ()" clause.
-    validate("WITH table AS () DELETE FROM table;", { false, { { "table" } } }, {}, "table", {}, false, false, {});
-    validate("WITH table (column) AS () DELETE FROM table;", { false, { { "table", { "column" } } } }, {}, "table", {}, false, false, {});
-    validate("WITH table (column1, column2) AS () DELETE FROM table;", { false, { { "table", { "column1", "column2" } } } }, {}, "table", {}, false, false, {});
-    validate("WITH RECURSIVE table AS () DELETE FROM table;", { true, { { "table", {} } } }, {}, "table", {}, false, false, {});
+    validate("DELETE FROM table;", {}, "table", {}, false, false, {});
+    validate("DELETE FROM schema.table;", "schema", "table", {}, false, false, {});
+    validate("DELETE FROM schema.table AS alias;", "schema", "table", "alias", false, false, {});
+    validate("DELETE FROM table WHERE (1 == 1);", {}, "table", {}, true, false, {});
+    validate("DELETE FROM table RETURNING *;", {}, "table", {}, false, true, {});
+    validate("DELETE FROM table RETURNING column;", {}, "table", {}, false, true, { {} });
+    validate("DELETE FROM table RETURNING column AS alias;", {}, "table", {}, false, true, { "alias" });
+    validate("DELETE FROM table RETURNING column1 AS alias1, column2 AS alias2;", {}, "table", {}, false, true, { "alias1", "alias2" });
 }
 
 TEST_CASE(select)
@@ -415,4 +373,60 @@ TEST_CASE(select)
     validate("SELECT * FROM table LIMIT 15 OFFSET 16;", all, from, false, 0, false, {}, true, true);
 }
 
+TEST_CASE(common_table_expression)
+{
+    EXPECT(parse("WITH DELETE FROM table;").is_error());
+    EXPECT(parse("WITH table DELETE FROM table;").is_error());
+    EXPECT(parse("WITH table AS DELETE FROM table;").is_error());
+    EXPECT(parse("WITH RECURSIVE table DELETE FROM table;").is_error());
+    EXPECT(parse("WITH RECURSIVE table AS DELETE FROM table;").is_error());
+
+    // Below are otherwise valid common-table-expressions, but attached to statements which do not allow them.
+    EXPECT(parse("WITH table AS (SELECT * AS TABLE) CREATE TABLE test ( column1 );").is_error());
+    EXPECT(parse("WITH table AS (SELECT * FROM table) DROP TABLE test;").is_error());
+
+    struct SelectedTableList {
+        struct SelectedTable {
+            StringView table_name {};
+            Vector<StringView> column_names {};
+        };
+
+        bool recursive { false };
+        Vector<SelectedTable> selected_tables {};
+    };
+
+    auto validate = [](StringView sql, SelectedTableList expected_selected_tables) {
+        auto result = parse(sql);
+        EXPECT(!result.is_error());
+
+        auto statement = result.release_value();
+        EXPECT(is<SQL::Delete>(*statement));
+
+        const auto& delete_ = static_cast<const SQL::Delete&>(*statement);
+
+        const auto& common_table_expression_list = delete_.common_table_expression_list();
+        EXPECT(!common_table_expression_list.is_null());
+
+        EXPECT_EQ(common_table_expression_list->recursive(), expected_selected_tables.recursive);
+
+        const auto& common_table_expressions = common_table_expression_list->common_table_expressions();
+        EXPECT_EQ(common_table_expressions.size(), expected_selected_tables.selected_tables.size());
+
+        for (size_t i = 0; i < common_table_expressions.size(); ++i) {
+            const auto& common_table_expression = common_table_expressions[i];
+            const auto& expected_common_table_expression = expected_selected_tables.selected_tables[i];
+            EXPECT_EQ(common_table_expression.table_name(), expected_common_table_expression.table_name);
+            EXPECT_EQ(common_table_expression.column_names().size(), expected_common_table_expression.column_names.size());
+
+            for (size_t j = 0; j < common_table_expression.column_names().size(); ++j)
+                EXPECT_EQ(common_table_expression.column_names()[j], expected_common_table_expression.column_names[j]);
+        }
+    };
+
+    validate("WITH table AS (SELECT * FROM table) DELETE FROM table;", { false, { { "table" } } });
+    validate("WITH table (column) AS (SELECT * FROM table) DELETE FROM table;", { false, { { "table", { "column" } } } });
+    validate("WITH table (column1, column2) AS (SELECT * FROM table) DELETE FROM table;", { false, { { "table", { "column1", "column2" } } } });
+    validate("WITH RECURSIVE table AS (SELECT * FROM table) DELETE FROM table;", { true, { { "table", {} } } });
+}
+
 TEST_MAIN(SqlStatementParser)
-- 
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