Files
ai-app/server/src/session/claude.rs
T

1541 lines
66 KiB
Rust

//! The Claude Code driver: `claude -p` speaking stream-json on stdio,
//! translated into the common event model.
//!
//! This half owns the process -- starting it, *adopting one this server
//! left running*, writing lines to it, and ending it. Where it runs is
//! `session::transport`'s business, not this file's: this one emits a
//! `Launch` and never learns whether it became a local child or an ssh
//! invocation.
//!
//! The process is meant to outlive the server, so that restarting the
//! backend does not end a turn: its stdio lives in the session directory
//! (a fifo it holds open itself, plus logs read from a byte offset) and
//! `session::process` records what it is. Everything comes through
//! [`ClaudeDriver::launch`], which adopts if it can and starts if it
//! cannot -- `--resume` is reachable only on the second path, because two
//! CLIs on one session file duplicate the conversation into it.
//! Turning a line into [`Event`]s is [`translate`], which changes when the
//! CLI's wire format does rather than when any of the above does.
//!
//! The probing record below stays here, since it is the provenance for
//! both halves: the flags are this file's, the message catalogue is what
//! `translate` implements.
//!
//! Wire format pinned against CLI 2.1.237 by probing (2026-08-24; scripts
//! summarized here since they live outside the repo):
//!
//! - Outbound: `system/init` (carries `session_id`, the `--resume` token),
//! `stream_event` (raw API deltas; `text_delta` is the streaming text),
//! consolidated `assistant` messages (their `tool_use` blocks have the
//! complete input), `user` messages with `tool_result` blocks, a `result`
//! per turn (usage + cost), `control_request` for anything needing a
//! human, `control_response` answering ours.
//! - Permission prompts require the hidden `--permission-prompt-tool stdio`
//! flag; they arrive as `control_request{subtype:can_use_tool}` and are
//! answered with `{behavior:"allow",updatedInput}` or
//! `{behavior:"deny",message}`. `AskUserQuestion` uses the same shape,
//! with the chosen labels added to `updatedInput` as
//! `answers:{<question text>:<label>}`.
//! - Inbound `user` messages sent mid-turn are queued and injected at the
//! next tool boundary (verified live: the model acknowledged a steer
//! between two Bash calls) -- the behavior this app exists for.
//! - `control_request{subtype:set_model}` answers success;
//! `{subtype:interrupt}` stops the turn.
//! - `control_request{subtype:set_permission_mode}` answers success and
//! echoes the mode back (`{"response":{"mode":"acceptEdits"}}`), so the
//! mode is changeable mid-session rather than only at spawn. Probed the
//! same way as the rest, against 2.1.237 on 2026-08-29.
use std::collections::VecDeque;
use std::path::{Path, PathBuf};
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::{Arc, Mutex};
use anyhow::{Context, Result};
use serde_json::{Value, json};
use tokio::io::AsyncWriteExt;
use tokio::sync::mpsc;
use super::driver::{AttachmentRef, Driver, Event, EventSink, SessionStatus, Unqueued};
use super::process;
use super::subagent::Subagents;
use super::transport::{Launch, Streams, Transport};
use crate::config::{ProviderConfig, SessionConfig};
use translate::{AnswerOutcome, Setting, Translator, starts_a_model_call};
/// How much of a failing process's stderr the exit report carries. Enough
/// for a shell's complaint plus the context it prints around it, and bounded
/// because this is held per session for the life of the process.
const STDERR_LINES_KEPT: usize = 50;
/// The kept stderr as one block, with blank lines trimmed off both ends. The
/// trailing trim is the point: a shell's error ends with a blank line, so
/// anything reporting "the last line" reports nothing at all.
fn tail_of(kept: &VecDeque<String>) -> String {
let lines: Vec<&str> = kept.iter().map(String::as_str).collect();
let start = lines
.iter()
.position(|line| !line.trim().is_empty())
.unwrap_or(lines.len());
let end = lines
.iter()
.rposition(|line| !line.trim().is_empty())
.map(|last| last + 1)
.unwrap_or(start);
lines[start..end].join("\n")
}
/// Where the driver remembers its CLI session id between backend runs -- the
/// whole crash-recovery story, since respawning with `--resume <id>` picks the
/// conversation back up. Kept in the session directory rather than config.ron
/// so the shared schema stays free of per-driver state.
pub(super) mod translate;
const RESUME_FILE: &str = "claude-session.json";
/// Messages handed to the CLI that it has not visibly acted on yet.
///
/// The CLI *does* take a message written mid-turn: it goes into the next model
/// call, which is the next tool boundary, and steering a running turn is the
/// point of this app. An earlier version held every mid-turn message until the
/// turn ended, so a steer sent after the second tool call sat unread until all
/// the work it was meant to redirect had finished.
///
/// What the CLI does not do is say on stdout that it has read one. So the line
/// goes out immediately and the *announcement* waits here, until the CLI opens
/// the next model call -- see [`translate::starts_a_model_call`].
///
/// The proof has to be the model call and not the output. Assistant text and a
/// tool call both keep arriving from a message that was *already in flight*
/// when the steer was written, and that message saw none of it: a steer sent
/// while an answer was streaming was recorded in the middle of it, above tool
/// calls the model had already committed to.
#[derive(Default)]
struct Queue {
/// A turn is in flight, so a message sent now is a steer into it.
running: bool,
/// Written, not yet announced, oldest first, each with the id of the
/// `MessageQueued` that told the phone it was waiting -- so the
/// announcement can name which bubble it resolves.
awaiting: VecDeque<(String, String, Vec<AttachmentRef>)>,
/// The process is gone, so nothing can be taken up any more.
///
/// Needed because every other way out of a turn is an `Idle` this driver
/// sees, and an exit is the one that is not. Without it a process that
/// died mid-turn left `running` true for good, and since a message is only
/// recorded when *announced*, each later one vanished silently.
closed: bool,
}
impl Queue {
/// Gives up on everything held, because the process is gone.
///
/// Reported rather than dropped: these are messages somebody typed that
/// never reached the session and never reached the transcript, so this is
/// the only place they can be mentioned at all.
///
/// Each is also *resolved*, with the same `MessageDropped` that tapping the
/// bubble produces -- otherwise the bubble sat there for good, waiting on a
/// `UserMessage` that is exactly what is not coming.
fn close(&mut self, sink: &EventSink, why: &str) {
self.closed = true;
self.running = false;
let lost: Vec<(String, String)> = self
.awaiting
.drain(..)
.map(|(id, text, _)| (id, text))
.collect();
if lost.is_empty() {
return;
}
let _ = sink.send(Event::Error {
message: format!(
"{why} before it read {}: {}",
if lost.len() == 1 {
"this message".to_string()
} else {
format!("{} queued messages", lost.len())
},
lost.iter()
.map(|(_, text)| text.as_str())
.collect::<Vec<_>>()
.join(" / ")
),
});
for (id, _) in lost {
let _ = sink.send(Event::MessageDropped { id });
}
}
}
/// The session directory's copies of the process's standard streams. Named
/// once rather than built at each use, because the spawn path and the attach
/// path must agree about which file is which; if they drift, a reattached
/// session reads a file nothing is writing and looks idle forever.
const STDIN_FIFO: &str = "stdin.fifo";
const STDOUT_LOG: &str = "stdout.log";
const STDERR_LOG: &str = "stderr.log";
/// How often a reader with nothing to read looks again. A poll rather than a
/// watch: the alternative is an inotify dependency for one file per session,
/// and at this interval the streaming text already arrives faster than a phone
/// renders it.
const POLL: std::time::Duration = std::time::Duration::from_millis(50);
pub struct ClaudeDriver {
sink: EventSink,
queue: Arc<Mutex<Queue>>,
/// Lines for the process's stdin. Not closeable, unlike the pipe this used
/// to be: stdin is a fifo the process holds open itself, so closing this
/// end says nothing to it. Ending the process is [`Driver::stop`]'s job.
to_child: mpsc::UnboundedSender<String>,
state: Arc<Mutex<Translator>>,
session_dir: PathBuf,
/// Cleared to stop the reader without touching the process -- which is
/// exactly what detaching is.
reading: Arc<AtomicBool>,
}
impl ClaudeDriver {
/// Takes charge of this session's process: the one already running if
/// there is one, otherwise a new one.
///
/// One entry point rather than two, because the choice is not the caller's
/// and getting it wrong is the expensive bug. A second `--resume` against
/// a session file that is already open duplicates the whole conversation
/// into it and bills the reattached copy for re-reading it -- measured at
/// 65 MB and 154 screenshots on 2026-08-29. So `--resume` is reachable
/// only through the spawn half below, under a check that nothing is
/// running.
pub fn launch(
meta: &SessionConfig,
provider: &ProviderConfig,
transport: &Transport,
session_dir: &Path,
sink: EventSink,
subagents: Arc<Subagents>,
) -> Result<Self> {
let state = Arc::new(Mutex::new(Translator::new(
session_dir.to_path_buf(),
subagents,
)));
let queue = Arc::new(Mutex::new(Queue::default()));
let reading = Arc::new(AtomicBool::new(true));
// Adopting is only possible for a process this server left behind on
// this machine: an ssh session's child died with the connection.
// Nothing was ever recorded for one, so this answers "no" without
// needing to know that.
//
// `started_here` is whether this launch *started* a process or picked
// one up; the two owe the session different things.
let started_here;
let record = match process::recorded(session_dir) {
// Still running, and ours. Pick it up where it was left -- the one
// path that must not pass `--resume`.
Some((record, process::Liveness::Alive)) => {
tracing::info!(
"session {} reattaching to the {} it left running (pid {})",
meta.id,
provider.name,
record.pid
);
started_here = false;
record
}
// Recorded, and the machine will not say whether it is still
// there. Starting one anyway is the mistake this module is for, so
// nothing is started; `follow` keeps asking.
Some((record, process::Liveness::Unknown)) => {
tracing::warn!(
"session {} recorded pid {} but this machine won't say whether it is running; \
not starting a second one",
meta.id,
record.pid
);
started_here = false;
record
}
Some((_, process::Liveness::Dead)) | None => {
started_here = true;
Self::start(meta, provider, transport, session_dir)?
}
};
// A process this driver has just started has been asked for nothing,
// which is what idle means. Said here because nothing else will: the
// CLI writes not one line until it is given work, so a session whose
// transcript last recorded `Exited` would keep that word -- and
// `Exited` refuses every command and invites starting a second CLI
// against a conversation that already has one.
//
// From the driver rather than the manager, and before `follow` is
// spawned, so it cannot overtake the exit `follow` reports for a
// process that dies immediately. Adopting says nothing, because a
// process already running may be mid-turn and the transcript's last
// word is the better answer until its output says otherwise.
if started_here {
let _ = sink.send(Event::Status {
state: SessionStatus::Idle,
});
}
// Where reading of its output had reached. A process just started has
// said nothing, so its record says zero.
let resuming_from = match record.detail {
process::Detail::Stdio { stdout_read } => stdout_read,
// A record of the wrong shape belongs to a different driver; read
// its output from the start rather than trusting an offset into a
// file that means something else.
_ => 0,
};
// The writer end of the fifo. Opened write-only here: the process holds
// its own read-write handle, so this side coming and going across a
// restart is invisible to it.
let stdin = std::fs::OpenOptions::new()
.write(true)
.open(session_dir.join(STDIN_FIFO))
.with_context(|| format!("opening {STDIN_FIFO} for session {}", meta.id))?;
let (to_child, mut from_driver) = mpsc::unbounded_channel::<String>();
tokio::spawn(async move {
let mut stdin = tokio::fs::File::from_std(stdin);
while let Some(line) = from_driver.recv().await {
if stdin.write_all(line.as_bytes()).await.is_err()
|| stdin.write_all(b"\n").await.is_err()
|| stdin.flush().await.is_err()
{
break;
}
}
});
tokio::spawn(follow(
session_dir.to_path_buf(),
record,
resuming_from,
Arc::clone(&state),
sink.clone(),
Arc::clone(&queue),
Arc::clone(&reading),
format!("{} {}", provider.name, transport.describe()),
));
Ok(Self {
sink,
queue,
to_child,
state,
session_dir: session_dir.to_path_buf(),
reading,
})
}
/// Starts a new CLI for this session, with its streams in the session
/// directory so the next run of this server can find them. The only path
/// that passes `--resume`, and it is reached only when nothing is running.
fn start(
meta: &SessionConfig,
provider: &ProviderConfig,
transport: &Transport,
session_dir: &Path,
) -> Result<process::Record> {
let mut args: Vec<String> = ["-p", "--verbose"].iter().map(|a| a.to_string()).collect();
let mut push = |flag: &str, value: &str| {
args.push(flag.to_string());
args.push(value.to_string());
};
push("--input-format", "stream-json");
push("--output-format", "stream-json");
// Hidden but load-bearing: without it the CLI resolves permissions
// itself and nothing ever reaches the phone.
push("--permission-prompt-tool", "stdio");
if let Some(model) = &meta.model {
push("--model", model);
}
if let Some(mode) = &meta.permission_mode {
push("--permission-mode", mode);
}
// Launch-only: see `SessionConfig::effort`. Omitted entirely when
// unset, so the CLI's own default is what an unchosen session gets
// rather than a level this app decided to call the default.
if let Some(effort) = &meta.effort {
push("--effort", effort);
}
// Named at birth, so this session is the same session in the CLI's own
// picker and in what other agents see.
//
// Only when we are creating it. A resume is a session that already
// existed -- an import, or this server starting again -- and it already
// has whatever name it was given, quite possibly by the person typing
// in it. `Driver::set_title` is how it changes after this point, and
// that one is asked for.
match read_resume_token(session_dir) {
Some(resume) => push("--resume", &resume),
None => push("--name", &meta.title),
}
args.push("--include-partial-messages".to_string());
// Makes `bypassPermissions` *reachable* without selecting it: the
// session still starts in whatever mode was asked for above.
//
// The CLI is asymmetric about that mode. It will *launch* in
// `bypassPermissions` on `--permission-mode` alone, but refuses to
// *switch* into it later ("the session was not launched with
// --dangerously-skip-permissions"), so the phone's mode picker offered
// a mode that could not be picked on every session not given it at
// birth. Since the mode is already reachable at spawn, this grants
// nothing that was being withheld.
//
// Measured against 2.1.237 both ways round. Note it is the `--allow-`
// form; `--dangerously-skip-permissions` turns it on for everything,
// which would take the choice away from whoever holds the phone.
args.push("--allow-dangerously-skip-permissions".to_string());
// Fresh logs, because the offsets that index them start at zero and
// everything the previous process said is already in the transcript.
let stdin = process::make_fifo(&session_dir.join(STDIN_FIFO))?;
let stdout = process::create_log(&session_dir.join(STDOUT_LOG))?;
let stderr = process::create_log(&session_dir.join(STDERR_LOG))?;
let program = provider.program();
let launch = Launch::new(program, args, meta.cwd.as_deref());
let child = transport.spawn(
&launch,
Streams::Detached {
stdin: stdin.into(),
stdout: stdout.into(),
stderr: stderr.into(),
},
)?;
let pid = child
.id()
.context("the process exited before it could be recorded")?;
tracing::info!(
"session {} running {program} {} as pid {pid}",
meta.id,
transport.describe()
);
// Reaped rather than waited on. This server is the parent, so something
// has to collect the exit status or the process becomes a zombie -- but
// `follow` decides what the session is doing, because after a restart
// there is no `Child` to wait on.
tokio::spawn(async move {
let mut child = child;
let _ = child.wait().await;
});
let record = process::Record::of(pid, process::Detail::Stdio { stdout_read: 0 })
.context("the process was gone before its start time could be read")?;
process::write(session_dir, &record);
Ok(record)
}
fn send_line(&self, line: String) {
let _ = self.to_child.send(line);
}
/// Writes one of the CLI's own commands into the session.
///
/// Slash commands ride the normal user-message channel -- there is no
/// control request for them, measured by asking. The turn they start is
/// marked here because they produce a `result` like any other, so a message
/// sent meanwhile belongs in the queue's "written, announce when read" path.
///
/// Nothing is emitted about the command itself: the manager has already
/// said it was sent, and the CLI announces what it does.
fn local_command(&self, text: String) {
let mut queue = self.queue.lock().unwrap();
// The same check `send_user_message` makes: a line written into a fifo
// nothing is reading goes nowhere and looks exactly like one that
// arrived. What this catches is the process going away between
// `Commands::submit`'s check and this write.
if queue.closed {
drop(queue);
let _ = self.sink.send(Event::Error {
message: format!("this session's process has exited, so it can't run {text}"),
});
return;
}
queue.running = true;
drop(queue);
// The session is working from this moment, and until now nothing said
// so: a command's reply carries no assistant text, so `proves_a_turn`
// never saw it and the recorded status stayed idle for the whole round
// trip -- which meant the *next* idle was not a change.
let _ = self.sink.send(Event::Status {
state: SessionStatus::Running,
});
self.send_line(
json!({"type": "user", "message": {"role": "user", "content": [
{"type": "text", "text": text}
]}})
.to_string(),
);
}
/// Sends a control request, remembering what it asked for.
///
/// `confirms` is the setting this request will have made if the CLI answers
/// success -- see [`Translator::expect_setting`]. `None` for the ones that
/// change no setting, like an interrupt.
///
/// The id is random rather than the clock it used to be: two requests in
/// the same second shared an id.
fn send_control(&self, request: Value, confirms: Option<Setting>) {
let id = format!("req-{}", super::random_hex());
if let Some(setting) = confirms {
// Before the line goes out: the reader thread is already running,
// and a fast answer to a slow lock arrives first.
self.state
.lock()
.unwrap()
.expect_setting(id.clone(), setting);
}
self.send_line(
json!({"type": "control_request", "request_id": id, "request": request}).to_string(),
);
}
}
impl Driver for ClaudeDriver {
fn send_user_message(&self, text: String, attachments: Vec<AttachmentRef>) {
let mut content = Vec::new();
// An image goes into the message itself; the model looks at it. Any
// other file stays where the upload put it and the message says where,
// because the CLI can read a file by path and a model cannot be handed
// a trace any other way. Named after the text, so the words come first.
let mut files = Vec::new();
for id in &attachments {
let sent = if crate::media::media_type_for(id).is_some() {
attachment_block(&self.session_dir, id).map(|block| content.push(block))
} else {
attachment_path(&self.session_dir, id).map(|path| files.push(path))
};
if let Err(err) = sent {
let _ = self.sink.send(Event::Error {
message: format!("attachment {id} couldn't be sent: {err:#}"),
});
}
}
let mut body = text.clone();
for path in files {
if !body.is_empty() {
body.push_str("\n\n");
}
body.push_str(&format!("Attached file: {}", path.display()));
}
if !body.is_empty() {
content.push(json!({"type": "text", "text": body}));
}
let line =
json!({"type": "user", "message": {"role": "user", "content": content}}).to_string();
let mut queue = self.queue.lock().unwrap();
// Saying so beats writing into a fifo that nothing is reading, which is
// what this used to do -- the message went nowhere and looked exactly
// like one that had been delivered.
if queue.closed {
drop(queue);
let _ = self.sink.send(Event::Error {
message: "this session's process has exited, so it can't be sent anything"
.to_string(),
});
return;
}
if queue.running {
// Into the running turn, now. Announced when the CLI shows it has
// been round the model again -- see `Queue`.
//
// The *waiting* is recorded here, which is the one thing that must
// not be left to the phone to remember: it drew the bubble from its
// own state, so leaving the session showed nothing pending while a
// message was still queued.
let id = super::random_hex();
queue
.awaiting
.push_back((id.clone(), text.clone(), attachments.clone()));
drop(queue);
let _ = self.sink.send(Event::MessageQueued {
id,
text,
attachments,
});
self.send_line(line);
return;
}
queue.running = true;
drop(queue);
// Nothing is in flight, so there is nothing to wait for: this message
// *is* the turn about to start, and it never had a `MessageQueued`.
let _ = self.sink.send(Event::MessageTaken {
id: None,
text,
attachments,
});
let _ = self.sink.send(Event::Status {
state: SessionStatus::Running,
});
self.send_line(line);
}
/// Never droppable, and that is a property of the design rather than an
/// omission. A message queued here has already been written to the CLI's
/// stdin -- see [`Queue`], where only the *announcement* waits -- because
/// that is what makes a steer reach the model at the next tool boundary.
/// A line in the fifo cannot be recalled.
fn unqueue(&self, id: &str) -> Unqueued {
let queue = self.queue.lock().unwrap();
if queue.awaiting.iter().any(|(waiting, ..)| waiting == id) {
Unqueued::AlreadySent
} else {
Unqueued::Unknown
}
}
fn answer_question(&self, id: &str, answers: &[String]) {
let response = {
let mut state = self.state.lock().unwrap();
state.answer(id, answers)
};
match response {
AnswerOutcome::Respond(control_response) => {
let _ = self.sink.send(Event::Status {
state: SessionStatus::Running,
});
self.send_line(control_response.to_string());
}
// A multi-question AskUserQuestion still waiting on the rest.
AnswerOutcome::Pending => {}
AnswerOutcome::Unknown => {
let _ = self.sink.send(Event::Error {
message: format!("no question {id} is awaiting an answer"),
});
}
}
}
/// Anything queued behind the interrupted turn still goes: it was typed
/// deliberately, and dropping it would lose a message that never reached
/// the transcript.
fn interrupt(&self) {
// Recorded before the request goes out, so the result it produces reads
// as the stop somebody asked for rather than as a failure.
self.state.lock().unwrap().expect_interrupt();
self.send_control(json!({"subtype": "interrupt"}), None);
}
fn set_permission_mode(&self, mode: &str) {
self.send_control(
json!({"subtype": "set_permission_mode", "mode": mode}),
Some(Setting::PermissionMode(mode.to_string())),
);
}
fn set_model(&self, model: &str) {
self.send_control(
json!({"subtype": "set_model", "model": model}),
Some(Setting::Model(model.to_string())),
);
}
fn run_command(&self, text: &str) {
// Whatever the CLI's own vocabulary holds. It rides the same channel as
// `/compact` and starts a turn the same way, so the same bookkeeping
// applies; what it means is the CLI's business.
self.local_command(text.to_string());
}
fn set_title(&self, title: &str) {
// The CLI's own mechanism, and a local command rather than a control
// request -- `set_session_name` is not a subtype it knows, measured by
// asking. It answers this the way it answers `/compact`. A name with a
// newline would be two lines and the second would be a message, so it
// is refused rather than sent.
if title.contains('\n') {
let _ = self.sink.send(Event::Error {
message: "a session name cannot contain a line break".to_string(),
});
return;
}
self.local_command(format!("/rename {title}"));
}
fn compact(&self) {
self.local_command("/compact".to_string());
}
fn clear(&self) {
// Nothing is emitted here on purpose: the transcript should record a
// clear that happened, not one that was asked for. The CLI announces it
// with `conversation_reset`, which `translate.rs` turns into
// `Event::Cleared`, and follows it with a fresh `init` whose new
// `session_id` the reader persists as the resume token.
self.local_command("/clear".to_string());
}
fn between_turns(&self) -> bool {
let queue = self.queue.lock().unwrap();
!queue.running && !queue.closed
}
fn detach(&self) {
// Stop reading and leave everything else exactly as it is. The process
// keeps its fifo, keeps writing its log, and keeps its record -- which
// is how the next run of this server finds it.
self.reading.store(false, Ordering::SeqCst);
}
fn stop(&self) {
self.reading.store(false, Ordering::SeqCst);
if let Some(record) = process::live(&self.session_dir) {
process::stop(&record, process::STOP_GRACE);
}
process::clear(&self.session_dir);
}
}
/// Follows the process's stdout log, turning it into events, and is also what
/// decides whether the session is still running.
///
/// One loop rather than a reader plus a monitor. After a restart there is no
/// `Child` to wait on -- the process was reparented away -- so liveness has to
/// be a question asked of the record either way, and asking it in two places is
/// how the two answers come to disagree.
///
/// Reading is resumable because the position is written down with the process:
/// everything before it is already in the transcript, so a server coming back
/// picks up exactly where the last one stopped.
#[allow(clippy::too_many_arguments)]
async fn follow(
session_dir: PathBuf,
mut record: process::Record,
mut offset: u64,
state: Arc<Mutex<Translator>>,
sink: EventSink,
queue: Arc<Mutex<Queue>>,
reading: Arc<AtomicBool>,
label: String,
) {
let stdout_path = session_dir.join(STDOUT_LOG);
let stderr_path = session_dir.join(STDERR_LOG);
// Whatever is already in the stderr log was logged by whichever run of this
// server was watching, so a reattach starts at the end of it. The tail is
// still read from the file if the process dies, which is when it matters.
let mut stderr_at = process::size_of(&stderr_path);
let mut said_unknown = false;
while reading.load(Ordering::SeqCst) {
let (bytes, _) = match process::read_from(&stdout_path, offset) {
Ok(found) => found,
Err(err) => {
// Reported, not only logged. This is the end of the session's
// output as far as anyone watching is concerned, and a phone
// told nothing shows a session that is merely quiet. The status
// is `Unknown` rather than `Exited` because the process may well
// still be running; what has failed is hearing it.
tracing::error!("couldn't read {}: {err:#}", stdout_path.display());
let _ = sink.send(Event::Error {
message: format!(
"lost track of {label}: its output can't be read ({err:#}). The process \
may still be running; restarting the backend will try to pick it up \
again."
),
});
queue
.lock()
.unwrap()
.close(&sink, "this server lost track of the session");
let _ = sink.send(Event::Status {
state: SessionStatus::Unknown,
});
return;
}
};
// Only whole lines, and the offset stops at the last newline -- so a
// line the process is halfway through writing is read again next pass.
// Deliberately *not* held in memory between passes: the offset would
// then have to point behind the bytes being held. It is also what makes
// the position crash-safe.
//
// Counted in bytes rather than on a decoded string: a read can cut a
// multi-byte character in half, and the replacement character is a
// different length from what it replaced -- which would slide the offset
// out of step with the file for the rest of the session.
let complete = complete_lines(&bytes);
for line in String::from_utf8_lossy(&bytes[..complete]).lines() {
if line.trim().is_empty() {
continue;
}
if !translate_line(line, &session_dir, &state, &sink, &queue) {
return; // session torn down
}
}
if complete > 0 {
offset += complete as u64;
record.detail = process::Detail::Stdio {
stdout_read: offset,
};
process::write(&session_dir, &record);
}
// Diagnostics only, and the tail of it is what an exit report carries --
// so it is read from the file rather than kept in memory, which means a
// reattached session can still explain a failure it did not witness.
if let Ok((bytes, at)) = process::read_from(&stderr_path, stderr_at)
&& at != stderr_at
{
stderr_at = at;
for line in String::from_utf8_lossy(&bytes).lines() {
if !line.trim().is_empty() {
tracing::warn!("{label} stderr: {line}");
}
}
}
match record.liveness() {
process::Liveness::Alive => said_unknown = false,
// Drain whatever it wrote on the way out before saying so.
//
// Progress, not "there were bytes": a process that died mid-line
// leaves a partial one that is re-read every pass and never
// completes, so waiting on a non-empty read would wait for ever.
process::Liveness::Dead if complete > 0 => {}
process::Liveness::Dead => {
queue.lock().unwrap().close(&sink, "the session ended");
let detail = stderr_tail(&stderr_path);
if !detail.is_empty() {
let _ = sink.send(Event::Error {
message: format!("{label} exited:\n{detail}"),
});
}
let _ = sink.send(Event::Status {
state: SessionStatus::Exited,
});
process::clear(&session_dir);
return;
}
// The record is there and the machine will not say whether the
// process behind it is. Reported rather than guessed: calling it
// exited would invite starting a second one against the same
// conversation. Kept polling, so it resolves itself.
process::Liveness::Unknown => {
if !said_unknown {
said_unknown = true;
let _ = sink.send(Event::Status {
state: SessionStatus::Unknown,
});
}
}
}
tokio::time::sleep(POLL).await;
}
}
/// How many leading bytes of `bytes` form complete lines. The offset only ever
/// advances by this, which is what lets a read land anywhere -- mid-line,
/// mid-character -- without the reader losing its place.
///
/// A line ends at `\n` and at nothing else, deliberately: this stream is JSONL,
/// so something terminated by a bare `\r` is not a record and treating one as a
/// line would hand `serde_json` a fragment. The accepted consequence is that
/// such a line is held here forever, and it is worth knowing what that looks
/// like, because it looks like nothing: the session goes quiet with the process
/// healthy and no error anywhere. The CLI has never written one here.
fn complete_lines(bytes: &[u8]) -> usize {
bytes
.iter()
.rposition(|byte| *byte == b'\n')
.map(|at| at + 1)
.unwrap_or(0)
}
/// One line of the CLI's output as events on the sink. `false` when the
/// session has been torn down and there is nothing left to send to.
fn translate_line(
line: &str,
session_dir: &Path,
state: &Arc<Mutex<Translator>>,
sink: &EventSink,
queue: &Arc<Mutex<Queue>>,
) -> bool {
let Ok(message) = serde_json::from_str::<Value>(line) else {
// By characters, not bytes: the CLI emits plenty of non-ASCII, and a
// byte slice that lands mid-character panics -- inside `follow`, so the
// session would go permanently deaf with nothing on screen to say so.
let shown: String = line.chars().take(200).collect();
tracing::warn!("unparseable claude output line: {shown}");
return true;
};
let opens_a_model_call = starts_a_model_call(&message);
let (events, new_session_id, before) = {
let mut state = state.lock().unwrap();
let before = state.session_id.clone();
let events = state.translate(&message);
let after = state.session_id.clone();
(events, if before != after { after } else { None }, before)
};
if let Some(session_id) = new_session_id {
write_resume_token(session_dir, &session_id);
}
// A turn the CLI began by itself, said one line earlier than anything else
// could say it.
//
// The CLI picks the conversation back up with nothing written to it --
// measured: a backgrounded `sleep` finished nine seconds after the turn's
// result and it started again unprompted. It announces that with an `init`,
// and the first assistant text follows about a second and a half later;
// until this, that read as idle, which is long enough to send a command into
// and have it read as text.
//
// `before.is_some()` separates this from the `init` at startup. Our own
// `/clear` also produces one, and is excluded by `running` already being
// true.
// `local_command` set it before the line went out.
if opens_a_turn_by_itself(&message, before.is_some()) {
let started = {
let mut queue = queue.lock().unwrap();
let started = !queue.running && !queue.closed;
if started {
queue.running = true;
}
started
};
if started
&& sink
.send(Event::Status {
state: SessionStatus::Running,
})
.is_err()
{
return false;
}
}
// The steer is announced where the CLI opens the model call that read it,
// and *before* that call's output, so the message sits above what it
// produced and below what it did not. This line carries no events of its
// own, which is what makes it the right place.
if opens_a_model_call && !announce_steers(queue, sink) {
return false;
}
for event in events {
// A turn nobody here started -- see `proves_a_turn`. Said before the
// event that proves it, for the same reason a steer is.
let started = {
let mut queue = queue.lock().unwrap();
let started = proves_a_turn(&event) && !queue.running && !queue.closed;
if started {
queue.running = true;
}
started
};
if started
&& sink
.send(Event::Status {
state: SessionStatus::Running,
})
.is_err()
{
return false;
}
// Either status the turn can end in -- see `SessionStatus::Waiting`.
// A turn that ended with a subagent still running is over for this
// queue's purposes: the CLI will read the next message, and holding
// one back until the subagent reported would sit on it indefinitely.
if matches!(
event,
Event::Status {
state: SessionStatus::Idle | SessionStatus::Waiting
}
) {
// The case that must not be missed: a message written after the
// final model call of a turn has no later `message_start` to prove
// anything, so without this it would never be announced at all. The
// end of the turn is where it belongs anyway.
if !announce_steers(queue, sink) {
return false;
}
queue.lock().unwrap().running = false;
}
if sink.send(event).is_err() {
return false; // session torn down
}
}
true
}
/// Whether this line is the CLI announcing work it started on its own.
///
/// `system/init` is how it says a conversation is beginning, and it sends one
/// at startup, after a `/clear`, and when it picks the conversation back up by
/// itself. Only the third is a turn nobody here asked for: `already_started`
/// rules out the first, and the caller's `running` check rules out the second.
fn opens_a_turn_by_itself(message: &Value, already_started: bool) -> bool {
already_started
&& message.get("type").and_then(Value::as_str) == Some("system")
&& message.get("subtype").and_then(Value::as_str) == Some("init")
}
/// Whether this event could only have come from a turn in flight.
///
/// The turn this side starts is announced where it is started, and that covers
/// the common case and nothing else. Everything below happens without a phone
/// asking: a compaction the CLI decided on itself, a session adopted mid-turn,
/// a message that reached the conversation by another route. In all of them the
/// CLI is plainly working and the only thing that would have said so is a
/// `Running` nobody sent, so the session reads as idle until the turn ends.
///
/// Deliberately a wider set than what announces a steer: any sign of work
/// proves a turn is running, while only a `message_start` proves a line written
/// a moment ago has been read.
fn proves_a_turn(event: &Event) -> bool {
matches!(
event,
Event::AssistantText { .. }
| Event::ToolStart { .. }
| Event::ToolUpdate { .. }
| Event::ToolEnd { .. }
| Event::Question { .. }
| Event::Compacted { .. }
| Event::Status {
state: SessionStatus::Compacting | SessionStatus::AwaitingInput
}
)
}
/// Records every message written since the last announcement, in the order it
/// was written. False means the session has been torn down.
///
/// Called from the two places that prove the CLI has consumed them: the start
/// of a new model call, and the end of the turn. The pair is the whole of the
/// rule -- a steer announced anywhere else lands above output that predates it.
fn announce_steers(queue: &Arc<Mutex<Queue>>, sink: &EventSink) -> bool {
let taken: Vec<(String, String, Vec<AttachmentRef>)> = {
let mut queue = queue.lock().unwrap();
queue.awaiting.drain(..).collect()
};
for (id, text, attachments) in taken {
if sink
.send(Event::MessageTaken {
id: Some(id),
text,
attachments,
})
.is_err()
{
return false;
}
}
true
}
/// The end of the stderr log, for an exit report a person reads. Bounded
/// because this is held in a message; trimmed of blank lines at both ends
/// because a shell's error ends with one, so anything reporting "the last
/// line" reports nothing at all. A failing `cd` cost an evening to that.
fn stderr_tail(path: &Path) -> String {
let Ok(text) = std::fs::read_to_string(path) else {
return String::new();
};
let kept: VecDeque<String> = text
.lines()
.rev()
.take(STDERR_LINES_KEPT)
.map(str::to_string)
.collect::<Vec<_>>()
.into_iter()
.rev()
.collect();
tail_of(&kept)
}
pub(super) fn read_resume_token(session_dir: &Path) -> Option<String> {
let text = std::fs::read_to_string(session_dir.join(RESUME_FILE)).ok()?;
serde_json::from_str::<Value>(&text)
.ok()?
.get("sessionId")?
.as_str()
.map(String::from)
}
pub(super) fn write_resume_token(session_dir: &Path, session_id: &str) {
let path = session_dir.join(RESUME_FILE);
if let Err(err) = std::fs::write(&path, json!({"sessionId": session_id}).to_string()) {
tracing::error!("couldn't persist resume token to {}: {err}", path.display());
}
}
/// Where an uploaded attachment is, as a path the CLI can be told.
///
/// Absolute, because the CLI's working directory is the session's and the
/// attachments are not in it. Refused rather than resolved when the id is not
/// one this server would have written, so a crafted id cannot name a file
/// outside the session.
fn attachment_path(session_dir: &Path, id: &str) -> Result<PathBuf> {
if !id
.chars()
.all(|c| c.is_ascii_alphanumeric() || c == '.' || c == '-' || c == '_')
|| id.contains("..")
{
anyhow::bail!("invalid attachment id");
}
let path = session_dir.join("attachments").join(id);
// A file copied to the session's own machine is named where it landed there
// -- `routes::upload_attachment` writes that down beside it -- because the
// path has to be one the CLI can open, not one this server can.
let shipped = path.with_file_name(format!("{id}.remote"));
if let Ok(remote) = std::fs::read_to_string(&shipped) {
return Ok(PathBuf::from(remote.trim()));
}
std::fs::canonicalize(&path).with_context(|| format!("find {}", path.display()))
}
/// Reads an uploaded image into an API image content block.
fn attachment_block(session_dir: &Path, id: &str) -> Result<Value> {
let path = attachment_path(session_dir, id)?;
let bytes = std::fs::read(&path).with_context(|| format!("read {}", path.display()))?;
use base64::Engine;
Ok(json!({
"type": "image",
"source": {
"type": "base64",
// Ids carry the extension the upload was stored under, so an
// unrecognized one means a name this server didn't write.
"media_type": crate::media::media_type_for(id).unwrap_or("image/jpeg"),
"data": base64::engine::general_purpose::STANDARD.encode(bytes),
}
}))
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn an_attachment_is_named_where_the_cli_can_open_it() {
let dir = tempfile::tempdir().expect("temp dir");
let attachments = dir.path().join("attachments");
std::fs::create_dir(&attachments).unwrap();
std::fs::write(attachments.join("ab12-x.bin"), b"x").unwrap();
assert_eq!(
attachment_path(dir.path(), "ab12-x.bin").unwrap(),
attachments.join("ab12-x.bin").canonicalize().unwrap()
);
// Shipped to the session's machine: the path there, not here.
std::fs::write(
attachments.join("ab12-x.bin.remote"),
"/home/t/in/ab12-x.bin\n",
)
.unwrap();
assert_eq!(
attachment_path(dir.path(), "ab12-x.bin").unwrap(),
PathBuf::from("/home/t/in/ab12-x.bin")
);
assert!(attachment_path(dir.path(), "../config.ron").is_err());
assert!(attachment_path(dir.path(), "missing.bin").is_err());
}
/// Drives real CLI output lines through the reader and collects what came
/// out, which is the only way to check the wiring between "the CLI said
/// this" and "the transcript records that".
fn events_from_lines(lines: &[&str]) -> Vec<Event> {
let dir = tempfile::tempdir().expect("temp dir");
let state = Arc::new(Mutex::new(Translator::new(
dir.path().to_path_buf(),
Arc::new(Subagents::new(dir.path().to_path_buf())),
)));
let queue = Arc::new(Mutex::new(Queue::default()));
let (sink, mut out) = mpsc::unbounded_channel::<Event>();
for line in lines {
assert!(translate_line(line, dir.path(), &state, &sink, &queue));
}
drop(sink);
let mut events = Vec::new();
while let Ok(event) = out.try_recv() {
events.push(event);
}
events
}
/// Feeds lines through the reader, running `interject` between two of them,
/// and returns what came out. The hook is what makes a steer testable at
/// all: what matters is not which events a line produces but *where* a
/// message written part-way through the stream ends up among them.
fn events_with_interjection(
lines: &[&str],
after: usize,
interject: impl FnOnce(&Arc<Mutex<Queue>>),
) -> Vec<Event> {
let dir = tempfile::tempdir().expect("temp dir");
let state = Arc::new(Mutex::new(Translator::new(
dir.path().to_path_buf(),
Arc::new(Subagents::new(dir.path().to_path_buf())),
)));
let queue = Arc::new(Mutex::new(Queue::default()));
let (sink, mut out) = mpsc::unbounded_channel::<Event>();
let mut interject = Some(interject);
for (i, line) in lines.iter().enumerate() {
assert!(translate_line(line, dir.path(), &state, &sink, &queue));
if i == after {
interject.take().expect("one interjection")(&queue);
}
}
drop(sink);
let mut events = Vec::new();
while let Ok(event) = out.try_recv() {
events.push(event);
}
events
}
/// One assistant message, streamed: two text deltas, then the `tool_use` it
/// ends with, then that call's result. Written out rather than shortened
/// because the point of both tests below is the *order*, and the shape of a
/// real turn is what makes the order mean anything. Recorded from 2.1.237.
const STREAMED_CALL: &[&str] = &[
r#"{"type":"stream_event","event":{"type":"message_start"},"session_id":"s","parent_tool_use_id":null}"#,
r#"{"type":"stream_event","event":{"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"Let me "}},"session_id":"s","parent_tool_use_id":null}"#,
r#"{"type":"stream_event","event":{"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"check that."}},"session_id":"s","parent_tool_use_id":null}"#,
r#"{"type":"assistant","message":{"role":"assistant","content":[{"type":"tool_use","id":"toolu_01","name":"Bash","input":{"command":"echo one"}}]},"parent_tool_use_id":null}"#,
r#"{"type":"user","message":{"role":"user","content":[{"tool_use_id":"toolu_01","type":"tool_result","content":"one","is_error":false}]},"parent_tool_use_id":null}"#,
];
/// A steer typed while an answer is streaming is recorded below that
/// answer's tool call and its result, not among them.
///
/// The message reaches the CLI immediately; what waits is saying so.
/// Everything emitted after it was typed still belongs to a model call that
/// had not read it. `message_start` is the first line that proves the next
/// call has it, so that is where the announcement goes.
#[test]
fn a_steer_is_recorded_below_the_call_that_had_not_read_it() {
let mut lines = STREAMED_CALL.to_vec();
lines.push(
r#"{"type":"stream_event","event":{"type":"message_start"},"session_id":"s","parent_tool_use_id":null}"#,
);
lines.push(
r#"{"type":"stream_event","event":{"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"Doing that instead."}},"session_id":"s","parent_tool_use_id":null}"#,
);
// Typed after the first delta, with the answer still arriving.
let events = events_with_interjection(&lines, 1, |queue| {
queue.lock().unwrap().awaiting.push_back((
"q1".into(),
"do the other one instead".into(),
Vec::new(),
))
});
let at = |find: fn(&Event) -> bool| {
events
.iter()
.position(find)
.unwrap_or_else(|| panic!("nothing matched in {events:?}"))
};
let taken = at(|e| matches!(e, Event::MessageTaken { .. }));
// Named, not just announced: the phone has a waiting bubble for this
// message and clears the one with this id. Matching on the text would
// clear the wrong bubble whenever the same thing was sent twice.
assert!(
matches!(
&events[taken],
Event::MessageTaken { id: Some(id), .. } if id == "q1"
),
"an announcement must name the queue entry it resolves: {events:?}"
);
assert!(
taken > at(|e| matches!(e, Event::ToolStart { .. })),
"a steer must not sit above a call the model had already made: {events:?}"
);
assert!(
taken > at(|e| matches!(e, Event::ToolEnd { .. })),
"a steer must not sit above the result of that call: {events:?}"
);
assert_eq!(
events
.iter()
.filter(|e| matches!(e, Event::AssistantText { .. }))
.count(),
3,
"the streamed answer must stay whole: {events:?}"
);
}
/// A steer written after the turn's last model call is still recorded.
/// Nothing further is coming, so no `message_start` will ever prove it was
/// read -- and a message only recorded when announced would vanish, leaving
/// a phone drawing it as waiting forever.
#[test]
fn a_steer_with_no_model_call_left_is_recorded_at_the_end_of_the_turn() {
let mut lines = STREAMED_CALL.to_vec();
lines.push(
r#"{"type":"result","subtype":"success","usage":{"input_tokens":1,"output_tokens":1}}"#,
);
// Typed after the tool result, with only the turn's end to come.
let events = events_with_interjection(&lines, 4, |queue| {
queue
.lock()
.unwrap()
.awaiting
.push_back(("q2".into(), "never mind".into(), Vec::new()))
});
let taken = events
.iter()
.position(|e| matches!(e, Event::MessageTaken { .. }))
.unwrap_or_else(|| panic!("a steer must never be dropped: {events:?}"));
let idle = events
.iter()
.position(|e| {
matches!(
e,
Event::Status {
state: SessionStatus::Idle
}
)
})
.unwrap_or_else(|| panic!("expected the turn to end: {events:?}"));
assert!(
taken < idle,
"the steer belongs inside the turn it was typed into: {events:?}"
);
}
/// The divider comes from the CLI announcing the reset, not from an `init`
/// arriving. Measured against 2.1.237: `/clear` emits `conversation_reset`,
/// then a fresh `init` carrying a new session id. Watching the id be
/// replaced would work, but it reads the event through a side effect; the
/// announcement says so directly and arrives first, so the divider lands
/// above the new conversation.
#[test]
fn a_conversation_reset_is_what_records_a_clear() {
let events = events_from_lines(&[
r#"{"type":"system","subtype":"init","session_id":"first","tools":[],"model":"claude-haiku-4-5-20251001"}"#,
r#"{"type":"conversation_reset","session_id":"first"}"#,
r#"{"type":"system","subtype":"init","session_id":"second","tools":[],"model":"claude-haiku-4-5-20251001"}"#,
]);
assert_eq!(
events.iter().filter(|e| **e == Event::Cleared).count(),
1,
"got {events:?}"
);
}
/// An `init` on its own never records a clear, whatever id it carries.
/// Three ways one arrives and none is a cleared conversation: the first
/// init of a session, the one a compaction re-announces carrying the *same*
/// id, and the one that follows a resume. Reading any as a clear would tell
/// the reader a conversation had been dropped when it had been summarised.
#[test]
fn an_init_alone_is_never_a_clear() {
for ids in [["first", "first"], ["first", "second"]] {
let events = events_from_lines(&[
&format!(
r#"{{"type":"system","subtype":"init","session_id":"{}","tools":[],"model":"claude-haiku-4-5-20251001"}}"#,
ids[0]
),
&format!(
r#"{{"type":"system","subtype":"init","session_id":"{}","tools":[],"model":"claude-haiku-4-5-20251001"}}"#,
ids[1]
),
]);
assert!(!events.contains(&Event::Cleared), "{ids:?} gave {events:?}");
}
}
/// The failure this exists for: a shell's complaint ends with a blank line,
/// so reporting "the last line of stderr" reported nothing, and the phone
/// showed a bare exit status while the reason sat in the server's log.
#[test]
fn the_report_keeps_the_message_and_not_the_blank_line_after_it() {
let fish_cd_failure = [
"cd: The directory '~/repos/ai-app' does not exist",
"",
"embedded:functions/cd.fish (line 26): ",
" builtin cd $argv",
" ^",
"in function 'cd' with arguments '~/repos/ai-app'",
"",
];
let kept: VecDeque<String> = fish_cd_failure.iter().map(|l| l.to_string()).collect();
let report = tail_of(&kept);
assert!(
report.starts_with("cd: The directory"),
"the complaint leads: {report}",
);
assert!(
report.ends_with("'~/repos/ai-app'"),
"the trailing blank is trimmed: {report:?}",
);
// The blank *between* lines is part of the message and stays.
assert!(report.contains("does not exist\n\nembedded:"), "{report:?}");
}
/// Nothing to say is said as nothing, so the caller can tell the two
/// apart and print just the exit status.
#[test]
fn stderr_that_is_only_blank_lines_reports_as_empty() {
let kept: VecDeque<String> = ["", " ", ""].iter().map(|l| l.to_string()).collect();
assert_eq!(tail_of(&kept), "");
assert_eq!(tail_of(&VecDeque::new()), "");
}
#[test]
fn a_stream_read_in_arbitrary_chunks_yields_each_line_once() {
// The property the reading position has to have: however a write is
// split -- mid-line, or mid-character -- every line comes out exactly
// once and in order. Chunked at every prime-ish size so the cuts land in
// different places, including inside the multi-byte character.
let stream = "{\"a\":1}\n{\"b\":\"caf\u{e9}\"}\n{\"c\":3}\n";
for chunk in [1usize, 2, 3, 5, 7, 11, 1000] {
let mut offset = 0usize;
let mut lines: Vec<String> = Vec::new();
let bytes = stream.as_bytes();
let mut available = 0usize;
while available < bytes.len() {
available = (available + chunk).min(bytes.len());
// What a read from the recorded offset returns: the file as far
// as it has been written, from where we left off.
let unread = &bytes[offset..available];
let complete = complete_lines(unread);
for line in String::from_utf8_lossy(&unread[..complete]).lines() {
lines.push(line.to_string());
}
offset += complete;
}
assert_eq!(offset, bytes.len(), "chunk {chunk} left bytes unread");
assert_eq!(
lines,
vec!["{\"a\":1}", "{\"b\":\"caf\u{e9}\"}", "{\"c\":3}"],
"chunk {chunk}"
);
}
}
#[test]
fn an_incomplete_line_advances_nothing() {
// Nothing to do yet, and crucially the position does not move -- so a
// crash here re-reads the line rather than skipping it.
assert_eq!(complete_lines(b"{\"partial\": tru"), 0);
assert_eq!(complete_lines(b""), 0);
// And a complete line followed by a partial one advances only past
// the complete one.
assert_eq!(complete_lines(b"done\nhalf"), 5);
}
#[test]
fn closing_the_queue_reports_what_was_never_read() {
let (sink, mut received) = mpsc::unbounded_channel();
let mut queue = Queue {
running: true,
..Queue::default()
};
queue
.awaiting
.push_back(("q1".into(), "first".into(), Vec::new()));
queue
.awaiting
.push_back(("q2".into(), "second".into(), Vec::new()));
queue.close(&sink, "the session ended");
// Named rather than counted, because these never reached the transcript:
// this message is the only record they existed.
let Some(Event::Error { message }) = received.try_recv().ok() else {
panic!("closing a queue holding messages must report them");
};
assert!(message.contains("2 queued messages"), "{message}");
assert!(message.starts_with("the session ended"), "{message}");
assert!(
message.contains("first") && message.contains("second"),
"{message}"
);
// And the flag is cleared, so a later message is refused with a reason
// rather than queued behind a turn that will never end.
assert!(!queue.running);
assert!(queue.closed);
}
#[test]
fn a_turn_this_side_did_not_start_still_reports_as_running() {
// The case: a session picked up while it was already working, or one
// another agent wrote to. Nothing called `send_user_message`, so the
// only thing that can say the session is busy is what it is observed
// doing.
let dir = tempfile::tempdir().expect("tempdir");
let (sink, mut received) = mpsc::unbounded_channel();
let state = Arc::new(Mutex::new(Translator::new(
dir.path().to_path_buf(),
Arc::new(Subagents::new(dir.path().to_path_buf())),
)));
let queue = Arc::new(Mutex::new(Queue::default()));
let text = r#"{"type":"stream_event","event":{"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"working"}},"parent_tool_use_id":null}"#;
assert!(translate_line(text, dir.path(), &state, &sink, &queue));
assert_eq!(
received.try_recv().ok(),
Some(Event::Status {
state: SessionStatus::Running
}),
"a turn in flight has to be reported before the output proving it"
);
assert!(matches!(
received.try_recv().ok(),
Some(Event::AssistantText { .. })
));
// Once only: the turn is known to be running now, and a status per delta
// would be a status per word.
assert!(translate_line(text, dir.path(), &state, &sink, &queue));
assert!(matches!(
received.try_recv().ok(),
Some(Event::AssistantText { .. })
));
// And the end of the turn puts it back, so the next one is
// reported the same way.
let done = r#"{"type":"result","subtype":"success","is_error":false,"usage":{}}"#;
assert!(translate_line(done, dir.path(), &state, &sink, &queue));
assert_eq!(
received.try_recv().ok(),
Some(Event::Status {
state: SessionStatus::Idle
})
);
assert!(!queue.lock().unwrap().running);
}
#[test]
fn output_from_a_process_that_has_gone_does_not_revive_the_turn() {
// `close` is what says the process is gone and reports the messages that
// died with it. Anything still in the pipe after that must not put the
// session back to work.
let dir = tempfile::tempdir().expect("tempdir");
let (sink, mut received) = mpsc::unbounded_channel();
let state = Arc::new(Mutex::new(Translator::new(
dir.path().to_path_buf(),
Arc::new(Subagents::new(dir.path().to_path_buf())),
)));
let queue = Arc::new(Mutex::new(Queue::default()));
queue.lock().unwrap().close(&sink, "the session ended");
let text = r#"{"type":"stream_event","event":{"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"late"}},"parent_tool_use_id":null}"#;
assert!(translate_line(text, dir.path(), &state, &sink, &queue));
assert!(matches!(
received.try_recv().ok(),
Some(Event::AssistantText { .. })
));
assert!(!queue.lock().unwrap().running);
}
#[test]
fn closing_an_empty_queue_says_nothing() {
let (sink, mut received) = mpsc::unbounded_channel();
let mut queue = Queue::default();
queue.close(&sink, "the session ended");
// A session that exits with nothing held has lost nothing, and an error
// saying so would be noise on every ordinary exit.
assert!(received.try_recv().is_err());
assert!(queue.closed);
}
}