004 bridge session hangup

// Test: `*Bridge<session!>` — the session is itself an obligation, and hanging
// up actually RELEASES what the session still holds.
//
// This is the first program that compiles `std/bridge` at all. The module has
// existed since 2026-07-24, is imported by nothing, and its `dischargeAll`
// printed a line and set a boolean while calling no discharger — the counter
// went to zero over a file that stayed open. `close` now PANICS if the session
// still holds anything when it returns, so the lie has nowhere to hide: the
// [BRIDGE] line below is the real discharger firing, and reaching the print at
// all is the assertion that nothing was stranded.
//
// The hang-up here is spelled out because this test is about `close` itself.
// 440_006 writes none: `close` is void, so auto-discharge inserts it.

~import std/bridge
~import std/runtime
~import std/io

const std = @import("std");

~pub tor open { path: string } -> string<opened!>

~proc open|zig {
    _ = path;
    return "file_1";
}

~pub tor close-file { handle: string<!opened> }

~proc close-file|zig {
    std.debug.print("close-file() ran for '{s}'\n", .{handle});
}

// The bridge's scope IS its vocabulary: the events that may act on what it
// holds, and — through each obligation's discharge event — how to let go.
~std/runtime:register(scope: "files") {
    open(10)
    close-file(1)
}

// create mints <session!>; only close discharges it. Drop the chain before
// close and the program does not compile.
~std/bridge:create(id: "session-1", scope: "files"): br |> turn-one(br): held |> std/bridge:close(br) |> std/io:print.ln("held before hang-up: {{ held:d }}")

// Turn one opens a file on the bridge and walks away from it. auto_discharge is
// off: a bridge-managed pool outlives the run by design, so nothing is released
// here — that is the session's job.
~tor turn-one { br: *std/bridge:Bridge } -> u32

~proc turn-one|zig {
    const rt = @import("root").koru_std.koru_runtime;
    _ = rt.run_event.handler(.{
        .source = "open(path: \"a.txt\")",
        .scope = "files",
        .budget = 100,
        .handle_pool = &br.pool,
        .auto_discharge = false,
    });
    return br.getHandleCount();
}