pi_agent_rust 0.8.0

Native AI coding agent CLI - Rust port of Pi Agent
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
//! Bounded, terminal-validated completions for tool-free auxiliary model calls.
//!
//! Deltas are previews, not a successful response. Only a clean terminal
//! message may become a side answer or an advisor verdict. The terminal
//! message is authoritative, including for providers that emit no deltas.

use futures::{Stream, StreamExt};

use crate::error::{Error, Result};
use crate::model::{ContentBlock, StopReason, StreamEvent};

mod request;
pub use request::with_timeout_and_abort;
pub use request::{RequestStop, with_timeout};

/// Auxiliary calls request only a few hundred tokens. Bound host-side output
/// too: a provider or extension is not obliged to honor max_tokens.
pub const MAX_TEXT_BYTES: usize = 64 * 1024;
const MAX_STREAM_EVENTS: usize = 65_536;
/// A ready stream must return control to its deadline/owner, not consume the
/// entire event budget in one poll. This is a scheduling bound, independent
/// of the request-wide event and output bounds.
const READY_EVENT_BATCH: usize = 64;
/// Bound the raw input before cloning or applying the detector. A projection
/// that cannot inspect a field must omit it, never send an unscreened prefix.
pub const MAX_INPUT_BYTES: usize = 256 * 1024;
const MAX_INPUT_PARTS: usize = 256;
pub const OMITTED_INPUT: &str = "[context omitted: auxiliary privacy scan budget]";

/// Compiled privacy policy for tool-free secondary model requests.
///
/// These requests never need executable credentials, so disabling the primary
/// agent's reversible vault does not disable their existing privacy floor.
/// Configured patterns extend that floor; block mode refuses the request.
#[derive(Clone, Debug, Default)]
pub struct AuxiliaryPrivacy {
    mode: crate::secrets::SecretsMode,
    extra_patterns: Vec<regex::Regex>,
}

impl AuxiliaryPrivacy {
    /// Provider-free checkpoints may redact locally even when outbound
    /// requests are blocked. Preserve the same configured detector patterns.
    pub(crate) fn local_redaction(&self) -> Self {
        Self {
            mode: crate::secrets::SecretsMode::Obfuscate,
            extra_patterns: self.extra_patterns.clone(),
        }
    }

    #[must_use]
    pub fn from_settings(settings: Option<&crate::secrets::SecretsSettings>) -> Self {
        let mode = crate::secrets::SecretsMode::from_setting(
            settings.and_then(|settings| settings.mode.as_deref()),
        );
        let extra_patterns = settings
            .and_then(|settings| settings.extra_patterns.as_deref())
            .map(crate::secrets::compile_extra_patterns)
            .unwrap_or_default();
        Self {
            mode: if mode == crate::secrets::SecretsMode::Block {
                mode
            } else {
                crate::secrets::SecretsMode::Obfuscate
            },
            extra_patterns,
        }
    }
}

/// Screen a complete set of text inputs before formatting or truncation.
///
/// Tool-free side requests never need executable credentials. These context
/// projections apply the built-in detector and configured patterns; block
/// mode refuses before provider admission. Discovery spans every part
/// before any replacement, so a later assignment also protects earlier bare
/// echoes. Disposable-vault IDs become non-restorable markers before a prompt
/// reaches another model or a verdict is injected into the main conversation.
/// Authentication headers and caller-owned text are not touched.
pub fn redact_inputs(parts: &[&str], privacy: &AuxiliaryPrivacy) -> Result<Vec<String>> {
    redact_inputs_with_vault(parts, privacy, &crate::secrets::SecretVault::default())
}

/// Preserve discoveries from the live conversation without sharing its
/// mutable vault or exporting reversible IDs to a secondary model.
pub fn redact_inputs_with_vault(
    parts: &[&str],
    privacy: &AuxiliaryPrivacy,
    known_secrets: &crate::secrets::SecretVault,
) -> Result<Vec<String>> {
    let bytes = parts
        .iter()
        .try_fold(0usize, |total, part| total.checked_add(part.len()));
    if parts.len() > MAX_INPUT_PARTS || bytes.is_none_or(|total| total > MAX_INPUT_BYTES) {
        return Err(Error::validation(
            "PI_AUXILIARY_INPUT_LIMIT: input exceeds the auxiliary privacy scan budget",
        ));
    }
    let mut vault = known_secrets.clone();
    let protected = redact_json_with_vault(&serde_json::json!(parts), privacy, &mut vault)?;
    let serde_json::Value::Array(protected) = protected else {
        return Err(Error::validation(
            "auxiliary privacy projection changed input shape",
        ));
    };
    protected
        .into_iter()
        .map(|part| match part {
            serde_json::Value::String(text) => Ok(text),
            _ => Err(Error::validation(
                "auxiliary privacy projection changed text type",
            )),
        })
        .collect()
}

/// Screen an already bounded structured projection. Callers own the input
/// budget: a full compaction has a larger allowance than a short side request.
/// Keeping JSON structure preserves assignment context and anchored patterns.
/// The supplied vault must be a private projection snapshot. Successful scans
/// retain discoveries for subsequent projections without changing a live Agent.
pub fn redact_json_with_vault(
    value: &serde_json::Value,
    privacy: &AuxiliaryPrivacy,
    known_secrets: &mut crate::secrets::SecretVault,
) -> Result<serde_json::Value> {
    let mut vault = known_secrets.clone();
    let (protected, _) = crate::secrets::transform_outbound_json(
        value,
        &mut vault,
        privacy.mode,
        &privacy.extra_patterns,
    )?;
    let protected = redact_json_placeholders(protected, &vault)?;
    *known_secrets = vault;
    Ok(protected)
}

fn redact_json_placeholders(
    value: serde_json::Value,
    vault: &crate::secrets::SecretVault,
) -> Result<serde_json::Value> {
    use serde_json::Value;
    match value {
        Value::String(text) => Ok(Value::String(vault.redact_placeholders(&text))),
        Value::Array(values) => values
            .into_iter()
            .map(|value| redact_json_placeholders(value, vault))
            .collect::<Result<Vec<_>>>()
            .map(Value::Array),
        Value::Object(values) => {
            let mut protected = serde_json::Map::new();
            for (key, value) in values {
                let key = vault.redact_placeholders(&key);
                let value = redact_json_placeholders(value, vault)?;
                if protected.insert(key, value).is_some() {
                    return Err(Error::validation(
                        "PI_AUXILIARY_KEY_COLLISION: redaction would merge structured fields",
                    ));
                }
            }
            Ok(Value::Object(protected))
        }
        primitive => Ok(primitive),
    }
}

/// Drain one tool-free completion without retaining cumulative previews.
///
/// Reject missing terminal events, transport/provider errors, incomplete stop
/// reasons, tool calls, empty answers, and oversized replies. A caller owns
/// the wall-clock deadline around both stream creation and this drain.
/// Ready streams yield after a bounded batch so that outer deadline and
/// cancellation futures are polled even when the provider never returns Pending.
pub async fn collect_text<S>(mut stream: S, max_bytes: usize) -> Result<String>
where
    S: Stream<Item = Result<StreamEvent>> + Unpin,
{
    let mut delta_bytes = 0usize;
    let mut event_count = 0usize;
    while let Some(event) = stream.next().await {
        event_count += 1;
        if event_count > MAX_STREAM_EVENTS {
            return Err(Error::api("text completion exceeded stream event budget"));
        }
        match event? {
            StreamEvent::TextDelta { delta, .. } => {
                delta_bytes = delta_bytes
                    .checked_add(delta.len())
                    .filter(|bytes| *bytes <= max_bytes)
                    .ok_or_else(|| Error::api("text completion exceeded output byte budget"))?;
            }
            StreamEvent::TextEnd { content, .. } if content.len() > max_bytes => {
                return Err(Error::api("text completion exceeded output byte budget"));
            }
            StreamEvent::ToolCallStart { .. }
            | StreamEvent::ToolCallDelta { .. }
            | StreamEvent::ToolCallEnd { .. } => {
                return Err(Error::api(
                    "tool-free text completion requested a tool call",
                ));
            }
            StreamEvent::Error { error, .. } => {
                return Err(Error::api(error.error_message.unwrap_or_else(|| {
                    "provider reported a failed text completion".to_string()
                })));
            }
            StreamEvent::Done { reason, message } => {
                if let Some(error) = message.error_message {
                    return Err(Error::api(error));
                }
                if reason != StopReason::Stop || message.stop_reason != StopReason::Stop {
                    return Err(Error::api(format!(
                        "text completion did not finish cleanly (event: {reason:?}, message: {:?})",
                        message.stop_reason
                    )));
                }
                let mut answer = String::new();
                for block in message.content {
                    match block {
                        ContentBlock::Text(text) => {
                            if text.text.len() > max_bytes.saturating_sub(answer.len()) {
                                return Err(Error::api(
                                    "text completion exceeded output byte budget",
                                ));
                            }
                            answer.push_str(&text.text);
                        }
                        ContentBlock::ToolCall(_) => {
                            return Err(Error::api(
                                "tool-free text completion requested a tool call",
                            ));
                        }
                        _ => {}
                    }
                }
                if answer.trim().is_empty() {
                    return Err(Error::api("text completion returned empty reply"));
                }
                return Ok(answer);
            }
            _ => {}
        }
        if event_count.is_multiple_of(READY_EVENT_BATCH) {
            yield_ready_batch().await;
        }
    }
    Err(Error::api(
        "text completion stream ended without Done event",
    ))
}

/// Yield exactly once after real progress. An idle provider is never
/// self-woken: its next() future continues to own readiness notification.
async fn yield_ready_batch() {
    let mut yielded = false;
    std::future::poll_fn(|cx| {
        if yielded {
            std::task::Poll::Ready(())
        } else {
            yielded = true;
            cx.waker().wake_by_ref();
            std::task::Poll::Pending
        }
    })
    .await;
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::model::{AssistantMessage, TextContent, ToolCall};
    use std::future::Future;
    use std::time::Duration;

    fn done(text: &str) -> StreamEvent {
        StreamEvent::Done {
            reason: StopReason::Stop,
            message: AssistantMessage {
                content: vec![ContentBlock::Text(TextContent::new(text))],
                stop_reason: StopReason::Stop,
                ..Default::default()
            },
        }
    }

    fn delta(text: &str) -> StreamEvent {
        StreamEvent::TextDelta {
            content_index: 0,
            delta: text.to_string(),
        }
    }

    async fn read(events: Vec<StreamEvent>, max_bytes: usize) -> Result<String> {
        collect_text(futures::stream::iter(events.into_iter().map(Ok)), max_bytes).await
    }

    #[test]
    fn input_discovery_protects_echoes_across_parts_without_exporting_vault_ids() {
        let secret = "r4nd0mCredentialValue123456";
        let assignment = format!("API_KEY={secret}");
        let parts = [secret, assignment.as_str(), "ordinary context"];
        let protected = redact_inputs(&parts, &AuxiliaryPrivacy::default()).unwrap();
        assert_eq!(
            protected,
            [
                "<pi-secret:redacted>",
                "API_KEY=<pi-secret:redacted>",
                "ordinary context",
            ]
        );
        assert_eq!(parts[0], secret, "source input is not mutated");
        let mut other_vault = crate::secrets::SecretVault::default();
        let _ = crate::secrets::obfuscate("sk-differentCredential123456789", &mut other_vault, &[]);
        assert_eq!(
            other_vault.restore(&protected.join("\n")),
            protected.join("\n")
        );
    }

    #[test]
    fn input_projection_handles_multiline_keys_and_preserves_clean_text_exactly() {
        let key = concat!(
            "-----BEGIN ",
            "PRIVATE KEY-----\nprivate\\material\"here\n-----END PRIVATE KEY-----"
        );
        let clean = "  α\r\n  code: C:\\work\\file\t\"quoted\"  ";
        let protected = redact_inputs(&[clean, key], &AuxiliaryPrivacy::default()).unwrap();
        assert_eq!(protected, [clean, "<pi-secret:redacted>"]);
        assert!(
            redact_inputs(&[], &AuxiliaryPrivacy::default())
                .unwrap()
                .is_empty()
        );
    }

    #[test]
    fn input_budget_refuses_without_exposing_or_slicing_the_input() {
        let input = "x".repeat(MAX_INPUT_BYTES);
        assert_eq!(
            redact_inputs(&[&input], &AuxiliaryPrivacy::default()).unwrap(),
            std::slice::from_ref(&input)
        );
        let error =
            redact_inputs(&[&input, "SECRET-CANARY"], &AuxiliaryPrivacy::default()).unwrap_err();
        assert!(error.to_string().contains("PI_AUXILIARY_INPUT_LIMIT"));
        assert!(!error.to_string().contains("SECRET-CANARY"));
        assert!(
            redact_inputs(&vec![""; MAX_INPUT_PARTS + 1], &AuxiliaryPrivacy::default()).is_err()
        );
    }

    #[test]
    fn configured_auxiliary_patterns_extend_the_privacy_floor_in_every_mode() {
        let custom = "ACME-123456";
        let built_in = "sk-abcdefghijklmnopqrstuvwxyz012345";
        for mode in [None, Some("obfuscate"), Some("off")] {
            let settings = crate::secrets::SecretsSettings {
                mode: mode.map(str::to_string),
                extra_patterns: Some(vec![r"ACME-\d{6}".to_string()]),
            };
            let privacy = AuxiliaryPrivacy::from_settings(Some(&settings));
            let protected = redact_inputs(&[custom, built_in, "clean context"], &privacy)
                .expect("obfuscated auxiliary fields");
            assert_eq!(
                protected,
                [
                    "<pi-secret:redacted>",
                    "<pi-secret:redacted>",
                    "clean context"
                ],
            );
        }
        let privacy = AuxiliaryPrivacy::from_settings(Some(&crate::secrets::SecretsSettings {
            mode: Some("block".to_string()),
            extra_patterns: Some(vec![r"ACME-\d{6}".to_string()]),
        }));
        for secret in [custom, built_in] {
            let error = redact_inputs(&["clean context", secret], &privacy).unwrap_err();
            assert!(error.to_string().contains("PI_SECRET_BLOCK"));
            assert!(!error.to_string().contains(secret));
        }
        assert_eq!(
            redact_inputs(&["clean context"], &privacy).unwrap(),
            ["clean context"],
        );
    }

    #[test]
    fn seeded_projection_protects_known_values_without_mutating_the_live_vault() {
        let known = "rememberedCredentialValue123456";
        let later = "anotherCredentialValue654321";
        let mut vault = crate::secrets::SecretVault::default();
        let _ = crate::secrets::obfuscate(&format!("API_KEY={known}"), &mut vault, &[]);
        let later_assignment = format!("API_KEY={later}");
        let protected = redact_inputs_with_vault(
            &[known, later, &later_assignment],
            &AuxiliaryPrivacy::default(),
            &vault,
        )
        .unwrap();
        assert_eq!(
            protected,
            [
                "<pi-secret:redacted>",
                "<pi-secret:redacted>",
                "API_KEY=<pi-secret:redacted>",
            ],
        );
        assert_eq!(
            vault.mask(later),
            later,
            "new discoveries remain disposable"
        );
        assert_eq!(vault.mask(known), "<pi-secret:000001>");
        let block = AuxiliaryPrivacy::from_settings(Some(&crate::secrets::SecretsSettings {
            mode: Some("block".to_string()),
            ..Default::default()
        }));
        let error = redact_inputs_with_vault(&[known], &block, &vault).unwrap_err();
        assert!(error.to_string().contains("PI_SECRET_BLOCK"));
        assert!(!error.to_string().contains(known));
    }

    #[test]
    fn terminal_only_provider_returns_its_answer() {
        asupersync::test_utils::run_test(|| async {
            assert_eq!(read(vec![done("complete")], 8).await.unwrap(), "complete");
        });
    }

    #[test]
    fn terminal_text_is_authoritative_and_not_duplicated() {
        asupersync::test_utils::run_test(|| async {
            let text = read(vec![delta("preview"), done("final answer")], 64)
                .await
                .unwrap();
            assert_eq!(text, "final answer");
        });
    }

    #[test]
    fn clean_done_does_not_wait_for_connection_close() {
        asupersync::test_utils::run_test(|| async {
            let stream =
                futures::stream::iter([Ok(done("done"))]).chain(futures::stream::pending());
            assert_eq!(collect_text(stream, 16).await.unwrap(), "done");
        });
    }

    #[test]
    fn partial_text_without_done_is_not_a_success() {
        asupersync::test_utils::run_test(|| async {
            let error = read(vec![delta("BLOCKER\nunfinished rationale")], 64)
                .await
                .unwrap_err();
            assert!(error.to_string().contains("without Done"));
            assert!(read(Vec::new(), 64).await.is_err());
        });
    }

    #[test]
    fn provider_error_after_text_is_not_a_success() {
        asupersync::test_utils::run_test(|| async {
            let error = StreamEvent::Error {
                reason: StopReason::Error,
                error: AssistantMessage {
                    error_message: Some("upstream unavailable".to_string()),
                    stop_reason: StopReason::Error,
                    ..Default::default()
                },
            };
            assert!(
                read(vec![delta("partial"), error], 64)
                    .await
                    .unwrap_err()
                    .to_string()
                    .contains("upstream unavailable")
            );
        });
    }

    #[test]
    fn transport_error_is_preserved() {
        asupersync::test_utils::run_test(|| async {
            let stream =
                futures::stream::iter([Ok(delta("partial")), Err(Error::api("connection reset"))]);
            assert!(
                collect_text(stream, 64)
                    .await
                    .unwrap_err()
                    .to_string()
                    .contains("connection reset")
            );
        });
    }

    #[test]
    fn incomplete_and_inconsistent_stop_reasons_are_rejected() {
        asupersync::test_utils::run_test(|| async {
            for stop in [
                StopReason::Length,
                StopReason::Error,
                StopReason::Aborted,
                StopReason::ToolUse,
                StopReason::PauseTurn,
            ] {
                let mut event = done("not complete");
                if let StreamEvent::Done { reason, .. } = &mut event {
                    *reason = stop;
                }
                assert!(read(vec![event], 64).await.is_err());
                let mut event = done("not complete");
                if let StreamEvent::Done { message, .. } = &mut event {
                    message.stop_reason = stop;
                }
                assert!(read(vec![event], 64).await.is_err());
            }
        });
    }

    #[test]
    fn clean_stop_with_error_payload_is_rejected() {
        asupersync::test_utils::run_test(|| async {
            let mut event = done("partial");
            if let StreamEvent::Done { message, .. } = &mut event {
                message.error_message = Some("failed".to_string());
            }
            assert!(read(vec![event], 64).await.is_err());
        });
    }

    #[test]
    fn empty_terminal_does_not_fall_back_to_stale_preview() {
        asupersync::test_utils::run_test(|| async {
            assert!(
                read(vec![delta("stale preview"), done(" \n")], 64)
                    .await
                    .is_err()
            );
        });
    }

    #[test]
    fn streaming_and_terminal_tool_calls_are_rejected() {
        asupersync::test_utils::run_test(|| async {
            let start = StreamEvent::ToolCallStart {
                content_index: 0,
                id: "call-1".to_string(),
                name: "bash".to_string(),
            };
            assert!(read(vec![start, done("answer")], 64).await.is_err());
            let mut event = done("answer");
            if let StreamEvent::Done { message, .. } = &mut event {
                message.content.push(ContentBlock::ToolCall(ToolCall {
                    id: "call-1".to_string(),
                    name: "bash".to_string(),
                    arguments: serde_json::json!({"command": "echo unexpected"}),
                    thought_signature: None,
                }));
            }
            assert!(read(vec![event], 64).await.is_err());
        });
    }

    #[test]
    fn output_budget_is_bytes_and_applies_to_deltas_and_terminal() {
        asupersync::test_utils::run_test(|| async {
            assert!(
                read(vec![delta("abcd"), delta("e"), done("ok")], 4)
                    .await
                    .is_err()
            );
            assert!(read(vec![done("abcde")], 4).await.is_err());
            assert!(read(vec![done("éé")], 3).await.is_err());
            assert_eq!(read(vec![done("éé")], 4).await.unwrap(), "éé");
        });
    }

    #[test]
    fn terminal_budget_is_shared_across_text_blocks() {
        asupersync::test_utils::run_test(|| async {
            let mut event = done("abc");
            if let StreamEvent::Done { message, .. } = &mut event {
                message
                    .content
                    .push(ContentBlock::Text(TextContent::new("def")));
            }
            assert!(read(vec![event.clone()], 5).await.is_err());
            assert_eq!(read(vec![event], 6).await.unwrap(), "abcdef");
        });
    }

    #[test]
    fn empty_delta_flood_is_bounded() {
        asupersync::test_utils::run_test(|| async {
            let stream = futures::stream::iter((0..=MAX_STREAM_EVENTS).map(|_| Ok(delta(""))));
            assert!(
                collect_text(stream, 64)
                    .await
                    .unwrap_err()
                    .to_string()
                    .contains("event budget")
            );
        });
    }

    #[test]
    fn zero_deadline_never_polls_request() {
        asupersync::test_utils::run_test(|| async {
            use std::sync::atomic::{AtomicBool, Ordering};
            let polled = AtomicBool::new(false);
            let result = with_timeout(Duration::ZERO, async {
                polled.store(true, Ordering::SeqCst);
                42
            })
            .await;
            assert_eq!(result, Err(RequestStop::TimedOut));
            assert!(!polled.load(Ordering::SeqCst));
        });
    }

    #[test]
    fn deadline_drops_pending_request() {
        asupersync::test_utils::run_test(|| async {
            use std::sync::Arc;
            use std::sync::atomic::{AtomicBool, Ordering};
            struct OnDrop(Arc<AtomicBool>);
            impl Drop for OnDrop {
                fn drop(&mut self) {
                    self.0.store(true, Ordering::SeqCst);
                }
            }
            let dropped = Arc::new(AtomicBool::new(false));
            let guard = OnDrop(Arc::clone(&dropped));
            let request = async move {
                let _guard = guard;
                futures::future::pending::<()>().await;
            };
            assert_eq!(
                with_timeout(Duration::from_millis(10), request).await,
                Err(RequestStop::TimedOut)
            );
            assert!(dropped.load(Ordering::SeqCst));
        });
    }

    #[test]
    fn ready_stream_returns_pending_after_each_bounded_batch() {
        use std::sync::atomic::{AtomicUsize, Ordering};
        let seen = AtomicUsize::new(0);
        let stream = futures::stream::iter((0..MAX_STREAM_EVENTS).map(|_| {
            seen.fetch_add(1, Ordering::SeqCst);
            Ok(delta(""))
        }));
        let mut request = std::pin::pin!(collect_text(stream, 64));
        let mut cx = std::task::Context::from_waker(futures::task::noop_waker_ref());
        for batch in 1..=3 {
            assert!(request.as_mut().poll(&mut cx).is_pending());
            assert_eq!(seen.load(Ordering::SeqCst), batch * READY_EVENT_BATCH);
        }
    }

    #[test]
    fn terminal_response_survives_multiple_cooperative_batches() {
        asupersync::test_utils::run_test(|| async {
            let stream = futures::stream::iter((0..READY_EVENT_BATCH * 3).map(|_| Ok(delta(""))))
                .chain(futures::stream::iter([Ok(done("complete"))]));
            assert_eq!(collect_text(stream, 64).await.unwrap(), "complete");
        });
    }

    #[test]
    fn idle_stream_does_not_self_wake() {
        use std::sync::Arc;
        use std::sync::atomic::{AtomicUsize, Ordering};
        struct WakeCount(AtomicUsize);
        impl futures::task::ArcWake for WakeCount {
            fn wake_by_ref(arc_self: &Arc<Self>) {
                arc_self.0.fetch_add(1, Ordering::SeqCst);
            }
        }
        let wakes = Arc::new(WakeCount(AtomicUsize::new(0)));
        let waker = futures::task::waker(Arc::clone(&wakes));
        let mut cx = std::task::Context::from_waker(&waker);
        let mut request = std::pin::pin!(collect_text(futures::stream::pending(), 64));
        assert!(request.as_mut().poll(&mut cx).is_pending());
        assert_eq!(wakes.0.load(Ordering::SeqCst), 0);
    }

    #[test]
    fn short_terminal_response_does_not_need_a_scheduling_round_trip() {
        let mut request = std::pin::pin!(collect_text(
            futures::stream::iter([Ok(done("complete"))]),
            64,
        ));
        let mut cx = std::task::Context::from_waker(futures::task::noop_waker_ref());
        assert!(matches!(
            request.as_mut().poll(&mut cx),
            std::task::Poll::Ready(Ok(answer)) if answer == "complete"
        ));
    }

    #[test]
    fn cancelling_after_a_ready_batch_stops_the_live_collector() {
        use std::sync::atomic::{AtomicUsize, Ordering};
        let runtime = asupersync::runtime::RuntimeBuilder::current_thread()
            .build()
            .unwrap();
        let owner = crate::agent_cx::AgentCx::from_cx(
            runtime.request_cx_with_budget(asupersync::Budget::new()),
        );
        runtime.block_on(async {
            let seen = AtomicUsize::new(0);
            let stream = futures::stream::iter((0..MAX_STREAM_EVENTS).map(|_| {
                seen.fetch_add(1, Ordering::SeqCst);
                Ok(delta(""))
            }));
            let mut request = std::pin::pin!(owner.with_current(with_timeout(
                Duration::from_secs(30),
                collect_text(stream, 64),
            )));
            assert!(futures::poll!(&mut request).is_pending());
            assert_eq!(seen.load(Ordering::SeqCst), READY_EVENT_BATCH);
            owner.cancel_with(
                asupersync::types::CancelKind::User,
                Some("stream cancelled"),
            );
            assert!(matches!(request.await, Err(RequestStop::Cancelled)));
            assert_eq!(seen.load(Ordering::SeqCst), READY_EVENT_BATCH);
            assert!(!asupersync::Cx::current().unwrap().is_cancel_requested());
        });
    }
}