fix: decouple oneliner-heal from request handler tasks

heal_orphans_if_idle called regenerate_missing_oneliners_for_user
inline on the request task, blocking the browser for up to N×60s
when orphans existed (observed with 16 cases after manual cleanup).

Now: CAS on new OnelinerHealBusy flag + tokio::spawn + BusyGuard
reset-on-drop. Handler returns immediately; the existing
OnelinerUpdated SSE event delivers results via the usual reload.
Startup recovery shares the flag so a concurrent page-load during
boot cannot fire a parallel regen loop against Ollama.

Regression test uses wiremock + timeout(150ms) + .expect(5) to
verify both non-blocking return and dedup of parallel invocations.

server/src/lib.rs

@@ -38,6 +38,12 @@ pub type WorkerBusy = Arc<AtomicBool>;
 pub struct AnalyzeBusy(pub WorkerBusy);
 #[derive(Clone)]
 pub struct TranscribeBusy(pub WorkerBusy);
+/// Dedup flag for the detached oneliner-heal `tokio::spawn` fired from
+/// `heal_orphans_if_idle`. The handler CAS's this to `true`; the spawned
+/// task resets via [`BusyGuard`] on drop. Keeps concurrent page-loads
+/// from launching parallel Ollama-call loops against the same data.
+#[derive(Clone)]
+pub struct OnelinerHealBusy(pub WorkerBusy);
 
 /// RAII guard that flips a [`WorkerBusy`] true on construction and false on
 /// drop — panic-safe. Shared across analyze + transcribe workers.
@@ -68,6 +74,7 @@ pub struct PipelineState {
     pub analyze_tx: AnalyzeSender,
     pub transcribe_busy: TranscribeBusy,
     pub transcribe_tx: TranscribeSender,
+    pub oneliner_heal_busy: OnelinerHealBusy,
 }
 
 /// Shared application state. Clonable — all fields are cheap to clone
@@ -81,6 +88,7 @@ pub struct AppState {
     pub magic_link_store: MagicLinkStore,
     pub analyze_busy: AnalyzeBusy,
     pub transcribe_busy: TranscribeBusy,
+    pub oneliner_heal_busy: OnelinerHealBusy,
     pub events_tx: events::EventSender,
     pub http_client: reqwest::Client,
     pub vocab: Arc<Gazetteer>,
@@ -128,6 +136,12 @@ impl FromRef<AppState> for TranscribeBusy {
     }
 }
 
+impl FromRef<AppState> for OnelinerHealBusy {
+    fn from_ref(state: &AppState) -> Self {
+        state.oneliner_heal_busy.clone()
+    }
+}
+
 impl FromRef<AppState> for PipelineState {
     fn from_ref(state: &AppState) -> Self {
         PipelineState {
@@ -135,6 +149,7 @@ impl FromRef<AppState> for PipelineState {
             analyze_tx: state.analyze_tx.clone(),
             transcribe_busy: state.transcribe_busy.clone(),
             transcribe_tx: state.transcribe_tx.clone(),
+            oneliner_heal_busy: state.oneliner_heal_busy.clone(),
         }
     }
 }
@@ -171,6 +186,7 @@ pub fn create_router(config: Arc<Config>) -> Router {
         magic_link_store: magic_link::new_store(),
         analyze_busy: AnalyzeBusy(Arc::new(AtomicBool::new(false))),
         transcribe_busy: TranscribeBusy(Arc::new(AtomicBool::new(false))),
+        oneliner_heal_busy: OnelinerHealBusy(Arc::new(AtomicBool::new(false))),
         events_tx: events::channel(),
         http_client: reqwest::Client::new(),
         vocab: Arc::new(Gazetteer::empty()),

server/src/main.rs

@@ -116,6 +116,12 @@ async fn main() {
     // subscribed browsers.
     let events_tx = events::channel();
 
+    // Dedup flag shared by the startup oneliner-regen task and every
+    // request-driven `heal_orphans_if_idle` spawn. One-at-a-time semantics
+    // keep Ollama from seeing overlapping regen loops.
+    let oneliner_heal_busy: doctate_server::WorkerBusy =
+        std::sync::Arc::new(std::sync::atomic::AtomicBool::new(false));
+
     // Transcription pipeline: channel + worker + recovery scan.
     let (transcribe_tx, transcribe_rx) = transcribe::channel();
     let transcribe_busy: doctate_server::WorkerBusy =
@@ -135,10 +141,14 @@ async fn main() {
         let cfg = config.clone();
         let vocab = vocab.clone();
         let events = events_tx.clone();
+        let heal_busy = oneliner_heal_busy.clone();
         tokio::spawn(async move {
             transcribe::recovery::scan_and_enqueue(&data_path, &tx).await;
             // Then catch up oneliners for cases that crashed between
             // transcript-write and oneliner-write in a previous run.
+            // Hold the shared heal-busy flag while running so a concurrent
+            // page-load does not spawn a second parallel regen loop.
+            let _guard = doctate_server::BusyGuard::new(heal_busy);
             transcribe::recovery::regenerate_missing_oneliners(
                 &data_path, &client, &cfg, &vocab, &events,
             )
@@ -174,6 +184,7 @@ async fn main() {
         magic_link_store: doctate_server::magic_link::new_store(),
         analyze_busy: doctate_server::AnalyzeBusy(analyze_busy),
         transcribe_busy: doctate_server::TranscribeBusy(transcribe_busy),
+        oneliner_heal_busy: doctate_server::OnelinerHealBusy(oneliner_heal_busy),
         events_tx,
         http_client,
         vocab,

server/src/routes/user_web.rs

@@ -11,7 +11,6 @@ use tracing::{info, warn};
 
 use time::{Date, OffsetDateTime, format_description::well_known::Rfc3339};
 
-use crate::PipelineState;
 use crate::analyze::{
     ANALYSIS_INPUT_FILE, DOCUMENT_FILE, auto_trigger, recovery as analyze_recovery,
 };
@@ -25,6 +24,7 @@ use crate::paths;
 use crate::routes::case_actions::read_document;
 use crate::routes::web::{RecordingView, scan_recordings};
 use crate::transcribe::recovery as transcribe_recovery;
+use crate::{BusyGuard, PipelineState};
 
 /// UI-layer oneliner status for the case list. Combines the persisted
 /// [`OnelinerState`] with derived transit states that only make sense
@@ -299,8 +299,8 @@ impl PipelineState {
         user_root: &Path,
         slug: &str,
         http_client: &reqwest::Client,
-        config: &Config,
-        vocab: &Gazetteer,
+        config: &Arc<Config>,
+        vocab: &Arc<Gazetteer>,
         events_tx: &EventSender,
     ) {
         if !self.analyze_busy.0.load(Ordering::Acquire) {
@@ -309,18 +309,45 @@ impl PipelineState {
         if !self.transcribe_busy.0.load(Ordering::Acquire) {
             transcribe_recovery::enqueue_pending_for_user(user_root, slug, &self.transcribe_tx)
                 .await;
-            // Oneliner self-heal: if the transcribe worker is busy, it will
-            // write a fresh oneliner at batch-end anyway — skip to avoid a
-            // redundant LLM call.
-            transcribe_recovery::regenerate_missing_oneliners_for_user(
-                user_root,
-                slug,
-                http_client,
-                config,
-                vocab,
-                events_tx,
-            )
-            .await;
+            // Oneliner self-heal: if the transcribe worker is busy, it
+            // will write a fresh oneliner at batch-end anyway — skip to
+            // avoid a redundant LLM call. Otherwise, fire the regen in a
+            // detached task so the request handler returns immediately;
+            // SSE `OnelinerUpdated` events deliver results to the browser.
+            // The CAS on `oneliner_heal_busy` guards against concurrent
+            // page-loads spawning their own parallel regen loops against
+            // the same cases.
+            if self
+                .oneliner_heal_busy
+                .0
+                .compare_exchange(false, true, Ordering::AcqRel, Ordering::Acquire)
+                .is_ok()
+            {
+                let user_root = user_root.to_path_buf();
+                let slug_owned = slug.to_owned();
+                let http_client = http_client.clone();
+                let config = Arc::clone(config);
+                let vocab = Arc::clone(vocab);
+                let events_tx = events_tx.clone();
+                let busy = Arc::clone(&self.oneliner_heal_busy.0);
+                info!(user = %slug, "oneliner heal spawned");
+                tokio::spawn(async move {
+                    // `BusyGuard::Drop` resets the flag to `false` — even
+                    // on panic inside the regen loop. The redundant
+                    // `store(true)` inside `BusyGuard::new` is harmless;
+                    // the CAS above already owns the flag transition.
+                    let _guard = BusyGuard::new(busy);
+                    transcribe_recovery::regenerate_missing_oneliners_for_user(
+                        &user_root,
+                        &slug_owned,
+                        &http_client,
+                        &config,
+                        &vocab,
+                        &events_tx,
+                    )
+                    .await;
+                });
+            }
         }
     }
 }

server/tests/magic_link_test.rs

@@ -11,7 +11,9 @@ use tower::util::ServiceExt;
 use doctate_common::API_KEY_HEADER;
 use doctate_server::config::{Config, User};
 use doctate_server::magic_link::{MagicLinkStore, PendingMagicLink};
-use doctate_server::{AnalyzeBusy, AppState, TranscribeBusy, analyze, transcribe, web_session};
+use doctate_server::{
+    AnalyzeBusy, AppState, OnelinerHealBusy, TranscribeBusy, analyze, transcribe, web_session,
+};
 
 const API_KEY: &str = "key-dr_a";
 
@@ -55,6 +57,7 @@ fn build_state() -> (AppState, Arc<Config>) {
         magic_link_store,
         analyze_busy: AnalyzeBusy(Arc::new(AtomicBool::new(false))),
         transcribe_busy: TranscribeBusy(Arc::new(AtomicBool::new(false))),
+        oneliner_heal_busy: OnelinerHealBusy(Arc::new(AtomicBool::new(false))),
         events_tx: doctate_server::events::channel(),
         http_client: reqwest::Client::new(),
         vocab: Arc::new(doctate_server::gazetteer::Gazetteer::empty()),

server/tests/oneliner_heal_decoupled_test.rs

@@ -0,0 +1,120 @@
+//! Regression test: `PipelineState::heal_orphans_if_idle` must not block
+//! the request handler on Ollama. Before the fix, the function awaited a
+//! sequential `regenerate_missing_oneliners_for_user` loop inline, so the
+//! HTTP handler stayed pinned for N × LLM-latency. The fix detaches the
+//! regeneration via `tokio::spawn`, guarded by a `compare_exchange` on
+//! `OnelinerHealBusy` to dedup concurrent page-loads.
+
+use std::path::Path;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::time::{Duration, Instant};
+
+use doctate_server::config::Config;
+use doctate_server::events;
+use doctate_server::gazetteer::Gazetteer;
+use doctate_server::{
+    AnalyzeBusy, OnelinerHealBusy, PipelineState, TranscribeBusy, WorkerBusy, analyze, transcribe,
+};
+use serde_json::json;
+use tempfile::tempdir;
+use tokio::time::timeout;
+use wiremock::matchers::{method, path as wm_path};
+use wiremock::{Mock, MockServer, ResponseTemplate};
+
+fn write_transcript(case_dir: &Path) {
+    let p = case_dir.join("2026-04-16T10-00-00Z.transcript.txt");
+    std::fs::write(p, "Brustschmerz links, seit heute morgen.").unwrap();
+}
+
+#[tokio::test]
+async fn heal_orphans_returns_fast_and_dedups_parallel_calls() {
+    // Five cases with a transcript but no oneliner.json. Without the fix,
+    // heal_orphans_if_idle would sequentially block on 5 × 200 ms = 1 s of
+    // mock delay. With the fix, it must return in well under that window.
+    let data = tempdir().unwrap();
+    let slug = "dr_test";
+    let user_root = data.path().join(slug);
+    std::fs::create_dir_all(&user_root).unwrap();
+    for i in 0..5 {
+        let case_dir = user_root.join(format!("case-{i:02}"));
+        std::fs::create_dir_all(&case_dir).unwrap();
+        write_transcript(&case_dir);
+    }
+
+    // Ollama mock: 200 ms delay per chat call. `.expect(5)` asserts at
+    // MockServer drop that exactly five requests arrived — dedup would
+    // show up as 10 without the CAS guard.
+    let mock = MockServer::start().await;
+    Mock::given(method("POST"))
+        .and(wm_path("/api/chat"))
+        .respond_with(
+            ResponseTemplate::new(200)
+                .set_delay(Duration::from_millis(200))
+                .set_body_json(json!({
+                    "message": { "content": "Brustschmerz links" }
+                })),
+        )
+        .expect(5)
+        .mount(&mock)
+        .await;
+
+    let mut cfg = Config::test_default();
+    cfg.data_path = data.path().to_path_buf();
+    cfg.ollama_url = mock.uri();
+    let config = Arc::new(cfg);
+
+    let vocab = Arc::new(Gazetteer::empty());
+    let events_tx = events::channel();
+    let http_client = reqwest::Client::new();
+
+    let (tx_a, _rx_a) = analyze::channel();
+    let (tx_t, _rx_t) = transcribe::channel();
+
+    let heal_busy: WorkerBusy = Arc::new(AtomicBool::new(false));
+    let pipeline = PipelineState {
+        analyze_busy: AnalyzeBusy(Arc::new(AtomicBool::new(false))),
+        analyze_tx: tx_a,
+        transcribe_busy: TranscribeBusy(Arc::new(AtomicBool::new(false))),
+        transcribe_tx: tx_t,
+        oneliner_heal_busy: OnelinerHealBusy(heal_busy.clone()),
+    };
+
+    // Two back-to-back heal invocations. The first wins the CAS and
+    // spawns. The second must no-op. Both heal futures themselves must
+    // finish in a fraction of the mock delay.
+    let before = Instant::now();
+    timeout(Duration::from_millis(150), async {
+        pipeline
+            .heal_orphans_if_idle(&user_root, slug, &http_client, &config, &vocab, &events_tx)
+            .await;
+        pipeline
+            .heal_orphans_if_idle(&user_root, slug, &http_client, &config, &vocab, &events_tx)
+            .await;
+    })
+    .await
+    .expect("heal_orphans_if_idle must return without awaiting the LLM loop");
+    assert!(
+        before.elapsed() < Duration::from_millis(150),
+        "heal_orphans returned in {:?} — the inline regen is back",
+        before.elapsed()
+    );
+
+    // Spawn drops the busy flag on completion — poll until idle.
+    let poll_start = Instant::now();
+    while heal_busy.load(Ordering::Acquire) {
+        if poll_start.elapsed() > Duration::from_secs(5) {
+            panic!("oneliner heal spawn did not finish within 5s");
+        }
+        tokio::time::sleep(Duration::from_millis(25)).await;
+    }
+
+    // Every case now has an oneliner.json.
+    for i in 0..5 {
+        let p = user_root.join(format!("case-{i:02}")).join("oneliner.json");
+        assert!(p.exists(), "oneliner.json missing for case-{i:02}");
+    }
+
+    // Mock is dropped at end of scope → `.expect(5)` verifies no
+    // double-firing. A failing expectation panics with the actual count.
+}