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ladybird/Tests/LibSQL/TestSqlExpressionParser.cpp
Jan de Visser 5c4890411b LibSQL: Make lexer and parser more standard SQL compliant 
SQL was standardized before there was consensus on sane language syntax
constructs had evolved. The language is mostly case-insensitive, with
unquoted text converted to upper case. Identifiers can include lower
case characters and other 'special' characters by enclosing the
identifier with double quotes. A double quote is escaped by doubling it.
Likewise, a single quote in a literal string is escaped by doubling it.

All this means that the strategy used in the lexer, where a token's
value is a StringView 'window' on the source string, does not work,
because the value needs to be massaged before being handed to the
parser. Therefore a token now has a String containing its value. Given
the limited lifetime of a token, this is acceptable overhead.

Not doing this means that for example quote removal and double quote
escaping would need to be done in the parser or in AST node
construction, which would spread lexing basically all over the place.
Which would be suboptimal.

There was some impact on the sql utility and SyntaxHighlighter component
which was addressed by storing the token's end position together with
the start position in order to properly highlight it.

Finally, reviewing the tests for parsing numeric literals revealed an
inconsistency in which tokens we accept or reject: `1a` is accepted but
`1e` is rejected. Related to this is the fate of `0x`. Added a FIXME
reminding us to address this.
2021-06-24 00:36:53 +02:00

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/*
* Copyright (c) 2021, Tim Flynn <trflynn89@pm.me>
* Copyright (c) 2021, Jan de Visser <jan@de-visser.net>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibTest/TestCase.h>
#include <AK/HashMap.h>
#include <AK/Result.h>
#include <AK/String.h>
#include <AK/StringBuilder.h>
#include <AK/StringView.h>
#include <AK/TypeCasts.h>
#include <LibSQL/AST/Lexer.h>
#include <LibSQL/AST/Parser.h>
namespace {
class ExpressionParser : public SQL::AST::Parser {
public:
explicit ExpressionParser(SQL::AST::Lexer lexer)
: SQL::AST::Parser(move(lexer))
{
}
NonnullRefPtr<SQL::AST::Expression> parse()
{
return SQL::AST::Parser::parse_expression();
}
};
using ParseResult = AK::Result<NonnullRefPtr<SQL::AST::Expression>, String>;
ParseResult parse(StringView sql)
{
auto parser = ExpressionParser(SQL::AST::Lexer(sql));
auto expression = parser.parse();
if (parser.has_errors()) {
return parser.errors()[0].to_string();
}
return expression;
}
}
TEST_CASE(numeric_literal)
{
// FIXME Right now the "1a" test fails (meaning the parse succeeds).
// This is obviously inconsistent.
// See the FIXME in lexer.cpp, method consume_exponent() about
// solutions.
// EXPECT(parse("1e").is_error());
// EXPECT(parse("1a").is_error());
// EXPECT(parse("0x").is_error());
auto validate = [](StringView sql, double expected_value) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::NumericLiteral>(*expression));
const auto& literal = static_cast<const SQL::AST::NumericLiteral&>(*expression);
EXPECT_EQ(literal.value(), expected_value);
};
validate("123", 123);
validate("3.14", 3.14);
validate("0xA", 10);
validate("0xff", 255);
validate("0x100", 256);
validate("1e3", 1000);
}
TEST_CASE(string_literal)
{
EXPECT(parse("'").is_error());
EXPECT(parse("'unterminated").is_error());
auto validate = [](StringView sql, StringView expected_value) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::StringLiteral>(*expression));
const auto& literal = static_cast<const SQL::AST::StringLiteral&>(*expression);
EXPECT_EQ(literal.value(), expected_value);
};
validate("''", "");
validate("'hello friends'", "hello friends");
validate("'hello ''friends'''", "hello 'friends'");
}
TEST_CASE(blob_literal)
{
EXPECT(parse("x'").is_error());
EXPECT(parse("x'unterminated").is_error());
EXPECT(parse("x'NOTHEX'").is_error());
auto validate = [](StringView sql, StringView expected_value) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::BlobLiteral>(*expression));
const auto& literal = static_cast<const SQL::AST::BlobLiteral&>(*expression);
EXPECT_EQ(literal.value(), expected_value);
};
validate("x''", "");
validate("x'DEADC0DE'", "DEADC0DE");
}
TEST_CASE(null_literal)
{
auto validate = [](StringView sql) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::NullLiteral>(*expression));
};
validate("NULL");
}
TEST_CASE(column_name)
{
EXPECT(parse(".column_name").is_error());
EXPECT(parse("table_name.").is_error());
EXPECT(parse("schema_name.table_name.").is_error());
EXPECT(parse("\"unterminated").is_error());
auto validate = [](StringView sql, StringView expected_schema, StringView expected_table, StringView expected_column) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::ColumnNameExpression>(*expression));
const auto& column = static_cast<const SQL::AST::ColumnNameExpression&>(*expression);
EXPECT_EQ(column.schema_name(), expected_schema);
EXPECT_EQ(column.table_name(), expected_table);
EXPECT_EQ(column.column_name(), expected_column);
};
validate("column_name", {}, {}, "COLUMN_NAME");
validate("table_name.column_name", {}, "TABLE_NAME", "COLUMN_NAME");
validate("schema_name.table_name.column_name", "SCHEMA_NAME", "TABLE_NAME", "COLUMN_NAME");
validate("\"Column_Name\"", {}, {}, "Column_Name");
validate("\"Column\n_Name\"", {}, {}, "Column\n_Name");
}
TEST_CASE(unary_operator)
{
EXPECT(parse("-").is_error());
EXPECT(parse("--").is_error());
EXPECT(parse("+").is_error());
EXPECT(parse("++").is_error());
EXPECT(parse("~").is_error());
EXPECT(parse("~~").is_error());
EXPECT(parse("NOT").is_error());
auto validate = [](StringView sql, SQL::AST::UnaryOperator expected_operator) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::UnaryOperatorExpression>(*expression));
const auto& unary = static_cast<const SQL::AST::UnaryOperatorExpression&>(*expression);
EXPECT_EQ(unary.type(), expected_operator);
const auto& secondary_expression = unary.expression();
EXPECT(!is<SQL::AST::ErrorExpression>(*secondary_expression));
};
validate("-15", SQL::AST::UnaryOperator::Minus);
validate("+15", SQL::AST::UnaryOperator::Plus);
validate("~15", SQL::AST::UnaryOperator::BitwiseNot);
validate("NOT 15", SQL::AST::UnaryOperator::Not);
}
TEST_CASE(binary_operator)
{
HashMap<StringView, SQL::AST::BinaryOperator> operators {
{ "||", SQL::AST::BinaryOperator::Concatenate },
{ "*", SQL::AST::BinaryOperator::Multiplication },
{ "/", SQL::AST::BinaryOperator::Division },
{ "%", SQL::AST::BinaryOperator::Modulo },
{ "+", SQL::AST::BinaryOperator::Plus },
{ "-", SQL::AST::BinaryOperator::Minus },
{ "<<", SQL::AST::BinaryOperator::ShiftLeft },
{ ">>", SQL::AST::BinaryOperator::ShiftRight },
{ "&", SQL::AST::BinaryOperator::BitwiseAnd },
{ "|", SQL::AST::BinaryOperator::BitwiseOr },
{ "<", SQL::AST::BinaryOperator::LessThan },
{ "<=", SQL::AST::BinaryOperator::LessThanEquals },
{ ">", SQL::AST::BinaryOperator::GreaterThan },
{ ">=", SQL::AST::BinaryOperator::GreaterThanEquals },
{ "=", SQL::AST::BinaryOperator::Equals },
{ "==", SQL::AST::BinaryOperator::Equals },
{ "!=", SQL::AST::BinaryOperator::NotEquals },
{ "<>", SQL::AST::BinaryOperator::NotEquals },
{ "AND", SQL::AST::BinaryOperator::And },
{ "OR", SQL::AST::BinaryOperator::Or },
};
for (auto op : operators) {
EXPECT(parse(op.key).is_error());
StringBuilder builder;
builder.append("1 ");
builder.append(op.key);
EXPECT(parse(builder.build()).is_error());
builder.clear();
if (op.key != "+" && op.key != "-") { // "+1" and "-1" are fine (unary operator).
builder.append(op.key);
builder.append(" 1");
EXPECT(parse(builder.build()).is_error());
}
}
auto validate = [](StringView sql, SQL::AST::BinaryOperator expected_operator) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::BinaryOperatorExpression>(*expression));
const auto& binary = static_cast<const SQL::AST::BinaryOperatorExpression&>(*expression);
EXPECT(!is<SQL::AST::ErrorExpression>(*binary.lhs()));
EXPECT(!is<SQL::AST::ErrorExpression>(*binary.rhs()));
EXPECT_EQ(binary.type(), expected_operator);
};
for (auto op : operators) {
StringBuilder builder;
builder.append("1 ");
builder.append(op.key);
builder.append(" 1");
validate(builder.build(), op.value);
}
}
TEST_CASE(chained_expression)
{
EXPECT(parse("()").is_error());
EXPECT(parse("(,)").is_error());
EXPECT(parse("(15,)").is_error());
auto validate = [](StringView sql, size_t expected_chain_size) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::ChainedExpression>(*expression));
const auto& chain = static_cast<const SQL::AST::ChainedExpression&>(*expression).expressions();
EXPECT_EQ(chain.size(), expected_chain_size);
for (const auto& chained_expression : chain)
EXPECT(!is<SQL::AST::ErrorExpression>(chained_expression));
};
validate("(15)", 1);
validate("(15, 16)", 2);
validate("(15, 16, column_name)", 3);
}
TEST_CASE(cast_expression)
{
EXPECT(parse("CAST").is_error());
EXPECT(parse("CAST (").is_error());
EXPECT(parse("CAST ()").is_error());
EXPECT(parse("CAST (15)").is_error());
EXPECT(parse("CAST (15 AS").is_error());
EXPECT(parse("CAST (15 AS)").is_error());
EXPECT(parse("CAST (15 AS int").is_error());
auto validate = [](StringView sql, StringView expected_type_name) {
auto result = parse(sql);
if (result.is_error())
outln("{}: {}", sql, result.error());
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::CastExpression>(*expression));
const auto& cast = static_cast<const SQL::AST::CastExpression&>(*expression);
EXPECT(!is<SQL::AST::ErrorExpression>(*cast.expression()));
const auto& type_name = cast.type_name();
EXPECT_EQ(type_name->name(), expected_type_name);
};
validate("CAST (15 AS int)", "INT");
// FIXME The syntax in the test below fails on both sqlite3 and psql (PostgreSQL).
// Also fails here because null is interpreted as the NULL keyword and not the
// identifier null (which is not a type)
// validate("CAST ('NULL' AS null)", "null");
validate("CAST (15 AS varchar(255))", "VARCHAR");
}
TEST_CASE(case_expression)
{
EXPECT(parse("CASE").is_error());
EXPECT(parse("CASE END").is_error());
EXPECT(parse("CASE 15").is_error());
EXPECT(parse("CASE 15 END").is_error());
EXPECT(parse("CASE WHEN").is_error());
EXPECT(parse("CASE WHEN THEN").is_error());
EXPECT(parse("CASE WHEN 15 THEN 16").is_error());
EXPECT(parse("CASE WHEN 15 THEN 16 ELSE").is_error());
EXPECT(parse("CASE WHEN 15 THEN 16 ELSE END").is_error());
auto validate = [](StringView sql, bool expect_case_expression, size_t expected_when_then_size, bool expect_else_expression) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::CaseExpression>(*expression));
const auto& case_ = static_cast<const SQL::AST::CaseExpression&>(*expression);
const auto& case_expression = case_.case_expression();
EXPECT_EQ(case_expression.is_null(), !expect_case_expression);
if (case_expression)
EXPECT(!is<SQL::AST::ErrorExpression>(*case_expression));
const auto& when_then_clauses = case_.when_then_clauses();
EXPECT_EQ(when_then_clauses.size(), expected_when_then_size);
for (const auto& when_then_clause : when_then_clauses) {
EXPECT(!is<SQL::AST::ErrorExpression>(*when_then_clause.when));
EXPECT(!is<SQL::AST::ErrorExpression>(*when_then_clause.then));
}
const auto& else_expression = case_.else_expression();
EXPECT_EQ(else_expression.is_null(), !expect_else_expression);
if (else_expression)
EXPECT(!is<SQL::AST::ErrorExpression>(*else_expression));
};
validate("CASE WHEN 16 THEN 17 END", false, 1, false);
validate("CASE WHEN 16 THEN 17 WHEN 18 THEN 19 END", false, 2, false);
validate("CASE WHEN 16 THEN 17 WHEN 18 THEN 19 ELSE 20 END", false, 2, true);
validate("CASE 15 WHEN 16 THEN 17 END", true, 1, false);
validate("CASE 15 WHEN 16 THEN 17 WHEN 18 THEN 19 END", true, 2, false);
validate("CASE 15 WHEN 16 THEN 17 WHEN 18 THEN 19 ELSE 20 END", true, 2, true);
}
TEST_CASE(exists_expression)
{
EXPECT(parse("EXISTS").is_error());
EXPECT(parse("EXISTS (").is_error());
EXPECT(parse("EXISTS (SELECT").is_error());
EXPECT(parse("EXISTS (SELECT)").is_error());
EXPECT(parse("EXISTS (SELECT * FROM table_name").is_error());
EXPECT(parse("NOT EXISTS").is_error());
EXPECT(parse("NOT EXISTS (").is_error());
EXPECT(parse("NOT EXISTS (SELECT").is_error());
EXPECT(parse("NOT EXISTS (SELECT)").is_error());
EXPECT(parse("NOT EXISTS (SELECT * FROM table_name").is_error());
EXPECT(parse("(").is_error());
EXPECT(parse("(SELECT").is_error());
EXPECT(parse("(SELECT)").is_error());
EXPECT(parse("(SELECT * FROM table_name").is_error());
auto validate = [](StringView sql, bool expected_invert_expression) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::ExistsExpression>(*expression));
const auto& exists = static_cast<const SQL::AST::ExistsExpression&>(*expression);
EXPECT_EQ(exists.invert_expression(), expected_invert_expression);
};
validate("EXISTS (SELECT * FROM table_name)", false);
validate("NOT EXISTS (SELECT * FROM table_name)", true);
validate("(SELECT * FROM table_name)", false);
}
TEST_CASE(collate_expression)
{
EXPECT(parse("COLLATE").is_error());
EXPECT(parse("COLLATE name").is_error());
EXPECT(parse("15 COLLATE").is_error());
auto validate = [](StringView sql, StringView expected_collation_name) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::CollateExpression>(*expression));
const auto& collate = static_cast<const SQL::AST::CollateExpression&>(*expression);
EXPECT(!is<SQL::AST::ErrorExpression>(*collate.expression()));
EXPECT_EQ(collate.collation_name(), expected_collation_name);
};
validate("15 COLLATE fifteen", "FIFTEEN");
validate("(15, 16) COLLATE \"chain\"", "chain");
}
TEST_CASE(is_expression)
{
EXPECT(parse("IS").is_error());
EXPECT(parse("IS 1").is_error());
EXPECT(parse("1 IS").is_error());
EXPECT(parse("IS NOT").is_error());
EXPECT(parse("IS NOT 1").is_error());
EXPECT(parse("1 IS NOT").is_error());
auto validate = [](StringView sql, bool expected_invert_expression) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::IsExpression>(*expression));
const auto& is_ = static_cast<const SQL::AST::IsExpression&>(*expression);
EXPECT(!is<SQL::AST::ErrorExpression>(*is_.lhs()));
EXPECT(!is<SQL::AST::ErrorExpression>(*is_.rhs()));
EXPECT_EQ(is_.invert_expression(), expected_invert_expression);
};
validate("1 IS NULL", false);
validate("1 IS NOT NULL", true);
}
TEST_CASE(match_expression)
{
HashMap<StringView, SQL::AST::MatchOperator> operators {
{ "LIKE", SQL::AST::MatchOperator::Like },
{ "GLOB", SQL::AST::MatchOperator::Glob },
{ "MATCH", SQL::AST::MatchOperator::Match },
{ "REGEXP", SQL::AST::MatchOperator::Regexp },
};
for (auto op : operators) {
EXPECT(parse(op.key).is_error());
StringBuilder builder;
builder.append("1 ");
builder.append(op.key);
EXPECT(parse(builder.build()).is_error());
builder.clear();
builder.append(op.key);
builder.append(" 1");
EXPECT(parse(builder.build()).is_error());
}
auto validate = [](StringView sql, SQL::AST::MatchOperator expected_operator, bool expected_invert_expression) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::MatchExpression>(*expression));
const auto& match = static_cast<const SQL::AST::MatchExpression&>(*expression);
EXPECT(!is<SQL::AST::ErrorExpression>(*match.lhs()));
EXPECT(!is<SQL::AST::ErrorExpression>(*match.rhs()));
EXPECT_EQ(match.type(), expected_operator);
EXPECT_EQ(match.invert_expression(), expected_invert_expression);
};
for (auto op : operators) {
StringBuilder builder;
builder.append("1 ");
builder.append(op.key);
builder.append(" 1");
validate(builder.build(), op.value, false);
builder.clear();
builder.append("1 NOT ");
builder.append(op.key);
builder.append(" 1");
validate(builder.build(), op.value, true);
}
}
TEST_CASE(null_expression)
{
EXPECT(parse("ISNULL").is_error());
EXPECT(parse("NOTNULL").is_error());
EXPECT(parse("15 NOT").is_error());
auto validate = [](StringView sql, bool expected_invert_expression) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::NullExpression>(*expression));
const auto& null = static_cast<const SQL::AST::NullExpression&>(*expression);
EXPECT_EQ(null.invert_expression(), expected_invert_expression);
};
validate("15 ISNULL", false);
validate("15 NOTNULL", true);
validate("15 NOT NULL", true);
}
TEST_CASE(between_expression)
{
EXPECT(parse("BETWEEN").is_error());
EXPECT(parse("NOT BETWEEN").is_error());
EXPECT(parse("BETWEEN 10 AND 20").is_error());
EXPECT(parse("NOT BETWEEN 10 AND 20").is_error());
EXPECT(parse("15 BETWEEN 10").is_error());
EXPECT(parse("15 BETWEEN 10 AND").is_error());
EXPECT(parse("15 BETWEEN AND 20").is_error());
EXPECT(parse("15 BETWEEN 10 OR 20").is_error());
auto validate = [](StringView sql, bool expected_invert_expression) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::BetweenExpression>(*expression));
const auto& between = static_cast<const SQL::AST::BetweenExpression&>(*expression);
EXPECT(!is<SQL::AST::ErrorExpression>(*between.expression()));
EXPECT(!is<SQL::AST::ErrorExpression>(*between.lhs()));
EXPECT(!is<SQL::AST::ErrorExpression>(*between.rhs()));
EXPECT_EQ(between.invert_expression(), expected_invert_expression);
};
validate("15 BETWEEN 10 AND 20", false);
validate("15 NOT BETWEEN 10 AND 20", true);
}
TEST_CASE(in_table_expression)
{
EXPECT(parse("IN").is_error());
EXPECT(parse("IN table_name").is_error());
EXPECT(parse("NOT IN").is_error());
EXPECT(parse("NOT IN table_name").is_error());
auto validate = [](StringView sql, StringView expected_schema, StringView expected_table, bool expected_invert_expression) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::InTableExpression>(*expression));
const auto& in = static_cast<const SQL::AST::InTableExpression&>(*expression);
EXPECT(!is<SQL::AST::ErrorExpression>(*in.expression()));
EXPECT_EQ(in.schema_name(), expected_schema);
EXPECT_EQ(in.table_name(), expected_table);
EXPECT_EQ(in.invert_expression(), expected_invert_expression);
};
validate("15 IN table_name", {}, "TABLE_NAME", false);
validate("15 IN schema_name.table_name", "SCHEMA_NAME", "TABLE_NAME", false);
validate("15 NOT IN table_name", {}, "TABLE_NAME", true);
validate("15 NOT IN schema_name.table_name", "SCHEMA_NAME", "TABLE_NAME", true);
}
TEST_CASE(in_chained_expression)
{
EXPECT(parse("IN ()").is_error());
EXPECT(parse("NOT IN ()").is_error());
auto validate = [](StringView sql, size_t expected_chain_size, bool expected_invert_expression) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::InChainedExpression>(*expression));
const auto& in = static_cast<const SQL::AST::InChainedExpression&>(*expression);
EXPECT(!is<SQL::AST::ErrorExpression>(*in.expression()));
EXPECT_EQ(in.expression_chain()->expressions().size(), expected_chain_size);
EXPECT_EQ(in.invert_expression(), expected_invert_expression);
for (const auto& chained_expression : in.expression_chain()->expressions())
EXPECT(!is<SQL::AST::ErrorExpression>(chained_expression));
};
validate("15 IN ()", 0, false);
validate("15 IN (15)", 1, false);
validate("15 IN (15, 16)", 2, false);
validate("15 NOT IN ()", 0, true);
validate("15 NOT IN (15)", 1, true);
validate("15 NOT IN (15, 16)", 2, true);
}
TEST_CASE(in_selection_expression)
{
EXPECT(parse("IN (SELECT)").is_error());
EXPECT(parse("IN (SELECT * FROM table_name, SELECT * FROM table_name);").is_error());
EXPECT(parse("NOT IN (SELECT)").is_error());
EXPECT(parse("NOT IN (SELECT * FROM table_name, SELECT * FROM table_name);").is_error());
auto validate = [](StringView sql, bool expected_invert_expression) {
auto result = parse(sql);
EXPECT(!result.is_error());
auto expression = result.release_value();
EXPECT(is<SQL::AST::InSelectionExpression>(*expression));
const auto& in = static_cast<const SQL::AST::InSelectionExpression&>(*expression);
EXPECT(!is<SQL::AST::ErrorExpression>(*in.expression()));
EXPECT_EQ(in.invert_expression(), expected_invert_expression);
};
validate("15 IN (SELECT * FROM table_name)", false);
validate("15 NOT IN (SELECT * FROM table_name)", true);
}
TEST_CASE(expression_tree_depth_limit)
{
auto too_deep_expression = String::formatted("{:+^{}}1", "", SQL::AST::Limits::maximum_expression_tree_depth);
EXPECT(!parse(too_deep_expression.substring_view(1)).is_error());
EXPECT(parse(too_deep_expression).is_error());
}
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