08 close without transaction

✓ Passing This code compiles and runs correctly.

Code

// TEST: Try to close a connection without using it
//
// connect() produces Connection[connected!]
// close() requires Connection[!active]
// These states don't match! You can't close a fresh connection.
//
// This is THE KEY INSIGHT: you MUST use the connection meaningfully
// before you can close it. Rust's Drop can't express this.
//
// EXPECTED: Compiler error - type mismatch (connected vs active)

~import "$app/db"

~app.db:connect(host: "localhost")
| ok c |>
    // Try to close immediately - this should FAIL!
    // close() needs [!active], but we have [connected!]
    app.db:close(conn: c.conn)
    | ok _ |> _
    | err _ |> _
| err _ |> _
input.kz

Error Verification

Expected Error Pattern

state mismatch

Actual Compiler Output 

error[KORU030]: Resource '__type_ref' [connected!] was not disposed. Call: begin
  --> auto_discharge:15:0

❌ Compiler coordination error: Auto-discharge failed (multiple disposal options or no disposal event)
error: CompilerCoordinationFailed
/Users/larsde/src/koru/tests/regression/900_EXAMPLES_SHOWCASE/910_LANGUAGE_SHOOTOUT/2104_08_close_without_transaction/backend.zig:9687:17: 0x102f8a4af in emit (backend)
                return error.CompilerCoordinationFailed;
                ^
/Users/larsde/src/koru/tests/regression/900_EXAMPLES_SHOWCASE/910_LANGUAGE_SHOOTOUT/2104_08_close_without_transaction/backend.zig:9771:28: 0x102f8b2b7 in main (backend)
    const generated_code = try RuntimeEmitter.emit(compile_allocator, final_ast);
                           ^

Imported Files

// Database module demonstrating phantom obligation semantics
//
// State machine:
//   connect()  → Connection[connected!]      -- must use connection
//   begin()    → Transaction[started!]       -- consumes conn, must exec
//   exec()     → Transaction[active!]        -- now can commit/rollback
//   commit()   → Connection[active!]         -- returns conn, can reuse or close
//   rollback() → Connection[active!]         -- returns conn, can reuse or close
//   close()    → void                        -- only accepts [!active], not [!connected]
//
// Key insight: close() requires [!active], which only comes from commit/rollback.
// This FORCES you to use the connection meaningfully before closing.

const std = @import("std");

const Connection = struct { handle: i32 };
const Transaction = struct { conn_handle: i32 };

// connect: creates connection with [connected!] obligation
~pub event connect { host: []const u8 }
| ok *Connection[connected!]
| err []const u8

~proc connect {
    const c = std.heap.page_allocator.create(Connection) catch unreachable;
    c.* = Connection{ .handle = 42 };
    return .{ .ok = c };
}

// begin: consumes [!connected] OR [!active], produces Transaction[started!]
~pub event begin { conn: *Connection[!connected|!active] }
| ok *Transaction[started!]
| err []const u8

~proc begin {
    const tx = std.heap.page_allocator.create(Transaction) catch unreachable;
    tx.* = Transaction{ .conn_handle = conn.handle };
    return .{ .ok = tx };
}

// exec: consumes [!started] OR [!active], produces Transaction[active!]
~pub event exec { tx: *Transaction[!started|!active], sql: []const u8 }
| ok *Transaction[active!]
| err []const u8

~proc exec {
    std.debug.print("Executing: {s}\n", .{sql});
    return .{ .ok = tx };
}

// commit: consumes [!active], returns Connection[active!]
~pub event commit { tx: *Transaction[!active] }
| ok *Connection[active!]
| err []const u8

~proc commit {
    std.debug.print("COMMIT\n", .{});
    const c = std.heap.page_allocator.create(Connection) catch unreachable;
    c.* = Connection{ .handle = tx.conn_handle };
    std.heap.page_allocator.destroy(tx);
    return .{ .ok = c };
}

// rollback: consumes [!active], returns Connection[active!]
~pub event rollback { tx: *Transaction[!active] }
| ok *Connection[active!]
| err []const u8

~proc rollback {
    std.debug.print("ROLLBACK\n", .{});
    const c = std.heap.page_allocator.create(Connection) catch unreachable;
    c.* = Connection{ .handle = tx.conn_handle };
    std.heap.page_allocator.destroy(tx);
    return .{ .ok = c };
}

// close: ONLY accepts [!active] - forces meaningful use before close
~pub event close { conn: *Connection[!active] }
| ok
| err []const u8

~proc close {
    std.debug.print("Connection closed\n", .{});
    std.heap.page_allocator.destroy(conn);
    return .{ .ok = .{} };
}
db.kz

Test Configuration

MUST_FAIL
← 07 serial transactions 09 empty transaction →