alopex-sql 0.8.7

SQL parser components for the Alopex DB dialect
Documentation
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use std::sync::{Arc, RwLock};

use alopex_core::kv::memory::MemoryKV;
use alopex_sql::catalog::MemoryCatalog;
use alopex_sql::dialect::AlopexDialect;
use alopex_sql::executor::{ExecutionResult, Executor, ExecutorError, QueryResult};
use alopex_sql::parser::Parser;
use alopex_sql::planner::{Planner, PlannerError};
use alopex_sql::storage::SqlValue;

fn execute_sql(sql: &str) -> Result<Vec<ExecutionResult>, ExecutorError> {
    let statements = Parser::parse_sql(&AlopexDialect, sql).expect("parse SQL");
    let catalog = Arc::new(RwLock::new(MemoryCatalog::new()));
    let store = Arc::new(MemoryKV::new());
    let mut executor = Executor::new(store, catalog.clone());
    let mut results = Vec::new();

    for statement in statements {
        let guard = catalog.read().expect("catalog lock");
        let plan = Planner::new(&*guard).plan(&statement)?;
        drop(guard);
        results.push(executor.execute(plan)?);
    }

    Ok(results)
}

fn last_query(sql: &str) -> QueryResult {
    execute_sql(sql)
        .expect("execute SQL")
        .into_iter()
        .rev()
        .find_map(|result| match result {
            ExecutionResult::Query(query) => Some(query),
            _ => None,
        })
        .expect("query result")
}

fn planner_error(sql: &str) -> PlannerError {
    let statement = Parser::parse_sql(&AlopexDialect, sql)
        .expect("parse SQL")
        .remove(0);
    let catalog = MemoryCatalog::new();

    Planner::new(&catalog)
        .plan(&statement)
        .expect_err("planning must fail")
}

#[test]
fn single_cte_executes() {
    let query = last_query(
        "CREATE TABLE t (id INT);\
         INSERT INTO t VALUES (1), (2);\
         WITH c AS (SELECT id FROM t) SELECT id FROM c ORDER BY id;",
    );

    assert_eq!(
        query.rows,
        vec![vec![SqlValue::Integer(1)], vec![SqlValue::Integer(2)]]
    );
}

#[test]
fn cte_column_name_list_renames_the_output_schema() {
    let query = last_query("WITH c(number) AS (SELECT 1) SELECT number FROM c;");

    assert_eq!(query.columns[0].name, "number");
    assert_eq!(query.rows, vec![vec![SqlValue::Integer(1)]]);
}

#[test]
fn cte_column_name_list_preserves_position_and_type() {
    let query = last_query(
        "WITH c(identifier, label) AS (SELECT 7, 'seven') \
         SELECT label, identifier FROM c;",
    );

    assert_eq!(
        query
            .columns
            .iter()
            .map(|column| column.name.as_str())
            .collect::<Vec<_>>(),
        vec!["label", "identifier"]
    );
    assert_eq!(
        query.rows,
        vec![vec![SqlValue::Text("seven".into()), SqlValue::Integer(7),]]
    );
}

#[test]
fn cte_column_name_count_mismatch_is_stable() {
    let error = planner_error("WITH c(col_one, col_two) AS (SELECT 1) SELECT col_one FROM c;");

    assert!(matches!(
        error,
        PlannerError::CteColumnCountMismatch {
            cte,
            declared: 2,
            actual: 1,
            ..
        } if cte == "c"
    ));
}

#[test]
fn duplicate_cte_column_name_is_rejected() {
    let error = planner_error("WITH c(value, value) AS (SELECT 1, 2) SELECT value FROM c;");

    assert!(matches!(
        error,
        PlannerError::DuplicateCteColumn { cte, name, .. }
            if cte == "c" && name == "value"
    ));
}

#[test]
fn cte_column_names_compose_with_shadowing_and_nested_with() {
    let query = last_query(
        "CREATE TABLE c (value INT);\
         INSERT INTO c VALUES (99);\
         WITH c(outer_value) AS (\
             WITH inner_cte(inner_value) AS (SELECT 7)\
             SELECT inner_value FROM inner_cte\
         )\
         SELECT outer_value FROM c;",
    );

    assert_eq!(query.rows, vec![vec![SqlValue::Integer(7)]]);
}

#[test]
fn quoted_cte_column_names_preserve_case_while_bare_names_fold() {
    let query = last_query(
        "WITH quoted(\"MixedCase\") AS (SELECT 1), bare(LOUD) AS (SELECT 2) \
         SELECT \"MixedCase\", loud FROM quoted, bare;",
    );

    assert_eq!(
        query
            .columns
            .iter()
            .map(|column| column.name.as_str())
            .collect::<Vec<_>>(),
        vec!["MixedCase", "loud"]
    );
    assert_eq!(
        query.rows,
        vec![vec![SqlValue::Integer(1), SqlValue::Integer(2)]]
    );
}

#[test]
fn cte_column_names_keep_cross_relation_ambiguity_checks() {
    let error = planner_error(
        "WITH left_cte(shared) AS (SELECT 1), right_cte(shared) AS (SELECT 2) \
         SELECT shared FROM left_cte, right_cte;",
    );

    assert!(matches!(
        error,
        PlannerError::AmbiguousColumn { column, .. } if column == "shared"
    ));
}

#[test]
fn recursive_cte_column_names_cross_the_parser_contract() {
    let statement = Parser::parse_sql(
        &AlopexDialect,
        "WITH RECURSIVE counter(n) AS (SELECT 1) SELECT n FROM counter;",
    )
    .expect("recursive CTE column names should parse")
    .remove(0);
    let alopex_sql::StatementKind::Select(select) = statement.kind else {
        panic!("expected SELECT");
    };
    let with = select.with.expect("expected WITH clause");

    assert!(with.recursive);
    assert_eq!(with.ctes[0].columns, vec!["n"]);
}

#[test]
fn multiple_ctes_execute_in_one_from_clause() {
    let query = last_query(
        "CREATE TABLE t (id INT);\
         INSERT INTO t VALUES (1), (2), (3);\
         WITH a AS (SELECT id FROM t WHERE id <= 2),\
              b AS (SELECT id FROM t WHERE id >= 2)\
         SELECT a.id, b.id FROM a, b ORDER BY a.id, b.id;",
    );

    assert_eq!(
        query.rows,
        vec![
            vec![SqlValue::Integer(1), SqlValue::Integer(2)],
            vec![SqlValue::Integer(1), SqlValue::Integer(3)],
            vec![SqlValue::Integer(2), SqlValue::Integer(2)],
            vec![SqlValue::Integer(2), SqlValue::Integer(3)],
        ]
    );
}

#[test]
fn cte_can_filter_and_aggregate() {
    let query = last_query(
        "CREATE TABLE t (id INT, category TEXT);\
         INSERT INTO t VALUES (1, 'skip'), (2, 'x'), (3, 'x'), (4, 'y');\
         WITH summary AS (\
             SELECT category, COUNT(*) AS item_count \
             FROM t WHERE id >= 2 GROUP BY category\
         )\
         SELECT category, item_count FROM summary ORDER BY category;",
    );

    assert_eq!(
        query.rows,
        vec![
            vec![SqlValue::Text("x".into()), SqlValue::BigInt(2)],
            vec![SqlValue::Text("y".into()), SqlValue::BigInt(1)],
        ]
    );
}

#[test]
fn cte_can_be_used_in_a_join() {
    let query = last_query(
        "CREATE TABLE users (id INT, name TEXT);\
         CREATE TABLE orders (user_id INT, total INT);\
         INSERT INTO users VALUES (1, 'alice'), (2, 'bob');\
         INSERT INTO orders VALUES (1, 40), (1, 75), (2, 20);\
         WITH large_orders AS (SELECT user_id, total FROM orders WHERE total >= 50)\
         SELECT users.name, large_orders.total \
         FROM users JOIN large_orders ON users.id = large_orders.user_id;",
    );

    assert_eq!(
        query.rows,
        vec![vec![SqlValue::Text("alice".into()), SqlValue::Integer(75),]]
    );
}

#[test]
fn cte_name_shadows_a_base_table() {
    let query = last_query(
        "CREATE TABLE sales (id INT);\
         INSERT INTO sales VALUES (1), (99);\
         WITH sales AS (SELECT id + 100 AS id FROM sales WHERE id = 1)\
         SELECT id FROM sales;",
    );

    assert_eq!(query.rows, vec![vec![SqlValue::Integer(101)]]);
}

#[test]
fn recursive_cte_union_all_reaches_a_fixed_point() {
    let query = last_query(
        "WITH RECURSIVE counter(n) AS (\
             SELECT 1 \
             UNION ALL \
             SELECT n + 1 FROM counter WHERE n < 5\
         )\
         SELECT n FROM counter ORDER BY n;",
    );

    assert_eq!(
        query.rows,
        vec![
            vec![SqlValue::Integer(1)],
            vec![SqlValue::Integer(2)],
            vec![SqlValue::Integer(3)],
            vec![SqlValue::Integer(4)],
            vec![SqlValue::Integer(5)],
        ]
    );
}

#[test]
fn recursive_cte_union_deduplicates_before_the_next_iteration() {
    let query = last_query(
        "WITH RECURSIVE cycle(n) AS (\
             SELECT 1 UNION SELECT n FROM cycle\
         )\
         SELECT n FROM cycle;",
    );

    assert_eq!(query.rows, vec![vec![SqlValue::Integer(1)]]);
}

#[test]
fn recursive_cte_walks_a_hierarchy() {
    let query = last_query(
        "CREATE TABLE employees (id INT, parent_id INT, name TEXT);\
         INSERT INTO employees VALUES\
             (1, NULL, 'root'), (2, 1, 'manager'), (3, 2, 'worker');\
         WITH RECURSIVE ancestors AS (\
             SELECT id, parent_id, name FROM employees WHERE id = 3\
             UNION ALL \
             SELECT employees.id, employees.parent_id, employees.name \
             FROM employees \
             JOIN ancestors ON employees.id = ancestors.parent_id\
         )\
         SELECT id, name FROM ancestors ORDER BY id;",
    );

    assert_eq!(
        query.rows,
        vec![
            vec![SqlValue::Integer(1), SqlValue::Text("root".into())],
            vec![SqlValue::Integer(2), SqlValue::Text("manager".into())],
            vec![SqlValue::Integer(3), SqlValue::Text("worker".into())],
        ]
    );
}

#[test]
fn with_recursive_without_self_reference_executes_as_an_ordinary_cte() {
    let query = last_query("WITH RECURSIVE c AS (SELECT 1 AS id) SELECT id FROM c;");

    assert_eq!(query.columns[0].name, "id");
    assert_eq!(query.rows, vec![vec![SqlValue::Integer(1)]]);
}

#[test]
fn with_recursive_non_self_union_executes_as_an_ordinary_cte() {
    let query = last_query("WITH RECURSIVE c(n) AS (SELECT 1 UNION ALL SELECT 2) SELECT n FROM c;");

    assert_eq!(
        query.rows,
        vec![vec![SqlValue::Integer(1)], vec![SqlValue::Integer(2)]]
    );
}

#[test]
fn with_recursive_forward_dependency_executes_as_ordinary_ctes() {
    let query = last_query(
        "WITH RECURSIVE a(value) AS (SELECT 7),\
                        b(copied) AS (SELECT value FROM a)\
         SELECT copied FROM b;",
    );

    assert_eq!(query.rows, vec![vec![SqlValue::Integer(7)]]);
}

#[test]
fn recursive_cte_can_derive_its_working_schema_from_the_anchor() {
    let query = last_query(
        "WITH RECURSIVE counter AS (\
             SELECT 1 AS n UNION ALL SELECT n + 1 FROM counter WHERE n < 3\
         ) SELECT n FROM counter ORDER BY n;",
    );

    assert_eq!(query.columns[0].name, "n");
    assert_eq!(
        query.rows,
        vec![
            vec![SqlValue::Integer(1)],
            vec![SqlValue::Integer(2)],
            vec![SqlValue::Integer(3)],
        ]
    );
}

#[test]
fn recursive_cte_rejects_duplicate_derived_anchor_names() {
    let error = planner_error(
        "WITH RECURSIVE ambiguous AS (\
             SELECT 1 AS value, 2 AS value UNION ALL \
             SELECT value + 1, value + 2 FROM ambiguous WHERE value < 2\
         ) SELECT value FROM ambiguous;",
    );

    assert!(
        matches!(&error, PlannerError::DuplicateCteColumn { cte, name, .. }
            if cte == "ambiguous" && name == "value"),
        "expected duplicate derived working-table names to fail closed, got: {error}"
    );
}

#[test]
fn recursive_cte_rejects_multiple_direct_self_references() {
    let sql = "WITH RECURSIVE c(n) AS (\
         SELECT 1 UNION ALL SELECT left_c.n FROM c AS left_c, c AS right_c\
     ) SELECT n FROM c;";
    let error = planner_error(sql);

    assert!(
        matches!(&error, PlannerError::UnsupportedFeature { feature, .. }
            if feature.contains("exactly one direct self-reference")),
        "expected a fail-closed self-reference error for `{sql}`, got: {error}"
    );
}

#[test]
fn recursive_cte_rejects_subqueries_in_the_recursive_term() {
    let error = planner_error(
        "WITH RECURSIVE c(n) AS (\
             SELECT 1 UNION ALL \
             SELECT n + (SELECT COUNT(*) FROM c) FROM c WHERE n < 2\
         ) SELECT n FROM c;",
    );

    assert!(
        matches!(&error, PlannerError::UnsupportedFeature { feature, .. }
            if feature.contains("subquery in a recursive term")),
        "expected recursive-term subqueries to fail closed, got: {error}"
    );
}

#[test]
fn recursive_cte_rejects_anchor_self_reference_and_non_union_shape() {
    for (sql, expected) in [
        (
            "WITH RECURSIVE c(n) AS (SELECT n FROM c UNION ALL SELECT 1) SELECT n FROM c;",
            "anchor term that does not reference itself",
        ),
        (
            "WITH RECURSIVE c(n) AS (SELECT 1 INTERSECT SELECT n FROM c) SELECT n FROM c;",
            "UNION or UNION ALL",
        ),
    ] {
        let error = planner_error(sql);
        assert!(
            matches!(&error, PlannerError::UnsupportedFeature { feature, .. }
                if feature.contains(expected)),
            "expected `{expected}` to be rejected for `{sql}`, got: {error}"
        );
    }
}

#[test]
fn recursive_cte_rejects_multiple_or_mutually_recursive_definitions() {
    let error = planner_error(
        "WITH RECURSIVE a(n) AS (SELECT 1 UNION ALL SELECT n FROM b),\
                        b(n) AS (SELECT 1 UNION ALL SELECT n FROM a)\
         SELECT n FROM a;",
    );

    assert!(
        matches!(&error, PlannerError::UnsupportedFeature { feature, .. }
            if feature.contains("exactly one common table expression")),
        "expected mutual recursion to be rejected before planning, got: {error}"
    );
}

#[test]
fn recursive_union_all_cycle_hits_a_stable_resource_limit() {
    let error = execute_sql(
        "WITH RECURSIVE cycle(n) AS (SELECT 1 UNION ALL SELECT n FROM cycle)\
         SELECT n FROM cycle;",
    )
    .expect_err("UNION ALL cycle must not run forever");

    assert!(
        matches!(&error, ExecutorError::ResourceExhausted { message }
            if message.contains("recursive CTE 'cycle'") && message.contains("iteration limit")),
        "expected a named recursive-CTE resource error, got: {error}"
    );
}

#[test]
fn undefined_cte_reference_is_an_error() {
    let statement = Parser::parse_sql(
        &AlopexDialect,
        "WITH defined AS (SELECT 1 AS id) SELECT id FROM missing",
    )
    .expect("parse CTE query")
    .remove(0);
    let catalog = MemoryCatalog::new();

    let error = Planner::new(&catalog)
        .plan(&statement)
        .expect_err("an undefined CTE reference must fail");

    assert!(
        matches!(
            &error,
            PlannerError::TableNotFound { name, .. } if name == "missing"
        ),
        "expected the missing CTE name in the error, got: {error}"
    );
}