fix: 优化下载并发调度，发布 1.0.2-beta4

direct-link（外部 .minecraft 关联）同步逻辑会把来源路径当作分组名
写入 instance_groups 表，每次同步都覆盖用户手动设置的分组，导致
分组当场生效、重启丢失。

移除三处 direct-link 相关的来源分组写入，使 instance_groups 表
专属于用户分组：
- sync_direct_link_instances: 同步时不再覆盖 groups
- create_direct_link_instance: 建实例时不再写来源分组
- launcher::promote_external_instance_link: 提升外部实例时不再写分组

Cargo.lock

@@ -6841,7 +6841,7 @@ dependencies = [
 
 [[package]]
 name = "theseus"
-version = "1.0.0-beta15"
+version = "1.0.2-beta4"
 dependencies = [
  "ariadne",
  "async-minecraft-ping",
@@ -6945,7 +6945,7 @@ dependencies = [
 
 [[package]]
 name = "theseus_gui"
-version = "1.0.0-beta15"
+version = "1.0.2-beta4"
 dependencies = [
  "ashpd",
  "async_zip",

apps/app-frontend/package.json

@@ -1,7 +1,7 @@
 {
 	"name": "@modrinth/app-frontend",
 	"private": true,
-	"version": "1.0.0-beta15",
+	"version": "1.0.2-beta4",
 	"type": "module",
 	"scripts": {
 		"dev": "vite",

apps/app-frontend/src/announcements/catalog.ts

@@ -32,6 +32,33 @@ export const ANNOUNCEMENT_CHANGE_TYPES: readonly AnnouncementChangeType[] = [
 ]
 
 export const launcherAnnouncements: readonly LauncherAnnouncement[] = [
+	{
+		id: 'launcher-1.0.2-beta4',
+		version: '1.0.2-beta4',
+		publishedAt: '2026-10-08',
+		title: {
+			'en-US': 'Starlight Launcher 1.0.2-beta4',
+			'zh-CN': 'Starlight Launcher 1.0.2-beta4',
+		},
+		changes: {
+			changed: [
+				{
+					'en-US': 'Improved download scheduling to reduce concurrency automatically when tasks are waiting for capacity, making large Minecraft installations more reliable on constrained connections.',
+					'zh-CN': '优化下载任务调度：任务因容量不足排队时会自动降低并发，提升大型 Minecraft 版本在受限网络环境下的安装稳定性。',
+				},
+			],
+			fixed: [
+				{
+					'en-US': 'Fixed downloads timing out while waiting for internal connection capacity, which could cause Minecraft installations to fail even when the network was available.',
+					'zh-CN': '修复下载任务等待内部连接容量时过早超时，导致网络正常的情况下 Minecraft 安装仍可能失败的问题。',
+				},
+				{
+					'en-US': 'Fixed instance group changes not saving for some instances.',
+					'zh-CN': '修复部分实例的分组修改无法保存的问题。',
+				},
+			],
+		},
+	},
 	{
 		id: 'launcher-1.0.2-beta3',
 		version: '1.0.2-beta3',

apps/app/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "theseus_gui"
 # The actual version is set by the theseus-build workflow on tagging
-version = "1.0.0-beta15"
+version = "1.0.2-beta4"
 edition.workspace = true
 description = "Axolotl Launcher is a cross-platform Minecraft launcher"
 homepage = "https://www.ghs.red"

packages/app-lib/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "theseus"
 # The actual version is set by the theseus-build workflow on tagging
-version = "1.0.0-beta15"
+version = "1.0.2-beta4"
 edition.workspace = true
 
 [dependencies]

packages/app-lib/src/launcher/download.rs

@@ -1947,8 +1947,8 @@ pub async fn download_assets(
     // failures. Runs concurrently (same budget as the original scheduler) so
     // import flows are not serialised.
     if !fallback_assets.is_empty() {
-        let limit = crate::util::download::task_concurrency_limit(st)
+        let limit =
-            .map(|limit| limit.saturating_mul(2))
+            crate::util::download::single_authority_task_concurrency_limit(st)
                 .unwrap_or(ASSET_BATCH_CONCURRENCY);
         futures::stream::iter(fallback_assets)
             .map(Ok::<FallbackAsset, crate::Error>)
@@ -2123,7 +2123,7 @@ pub async fn download_libraries(
     let num_files = tasks.len();
     loading_try_for_each_concurrent(
 		stream::iter(tasks).map(Ok::<LibraryDownloadTask<'_>, crate::Error>),
-		crate::util::download::task_concurrency_limit(&st).map(|limit| limit.saturating_mul(2)),
+		crate::util::download::task_concurrency_limit(&st),
         loading_bar,
         loading_amount,
         num_files,

packages/app-lib/src/launcher/mod.rs

@@ -1,5 +1,4 @@
 //! Logic for launching Minecraft
-use crate::api::pack::import::direct_link::direct_link_group;
 use crate::data::ModLoader;
 use crate::event::emit::{emit_instance, emit_loading, init_loading};
 use crate::event::{InstancePayloadType, LoadingBarType};
@@ -717,14 +716,6 @@ async fn promote_external_instance_link(
         &mut tx,
     )
     .await?;
-    if let Some(group) = direct_link_group(&direct.dot_minecraft) {
-        crate::state::instances::adapters::sqlite::instance_rows::replace_instance_groups(
-            &instance.id,
-            &[group],
-            &mut tx,
-        )
-        .await?;
-    }
     tx.commit().await?;
     emit_instance(&instance.id, InstancePayloadType::Edited).await?;
     Ok(())

packages/app-lib/src/state/instances/commands/create_direct_link_instance.rs

@@ -1,6 +1,6 @@
 use crate::api::pack::import::{
     ImportLauncherType,
-    direct_link::{direct_link_group, resolve_direct_link},
+    direct_link::resolve_direct_link,
 };
 use crate::launcher::ExternalGameDirMode;
 use crate::state::instances::{
@@ -156,11 +156,6 @@ pub(crate) async fn create_direct_link_instance(
         &mut tx,
     )
     .await?;
-    let groups = direct_link_group(&resolved.dot_minecraft)
-        .into_iter()
-        .collect::<Vec<_>>();
-    instance_rows::replace_instance_groups(&instance_id, &groups, &mut tx)
-        .await?;
     instance_rows::upsert_instance_launch_overrides(&launch_overrides, &mut tx)
         .await?;
     tx.commit().await?;

packages/app-lib/src/state/instances/commands/sync_direct_link_instances.rs

@@ -1,6 +1,6 @@
 use super::create_direct_link_instance::create_direct_link_instance;
 use crate::api::pack::import::direct_link::{
-    detect_direct_link_source, direct_link_group,
+    detect_direct_link_source,
     has_minecraft_version_manifest, resolve_direct_link,
 };
 use crate::event::{InstancePayloadType, emit::emit_instance};
@@ -163,11 +163,7 @@ pub(crate) async fn sync_direct_link_instances(
                 let content_changed = metadata.applied_content_set.game_version
                     != resolved.game_version
                     || metadata.applied_content_set.loader != resolved.loader;
-                let groups = direct_link_group(&resolved.dot_minecraft)
+                if fields_changed || content_changed {
-                    .into_iter()
-                    .collect::<Vec<_>>();
-                let groups_changed = metadata.groups != groups;
-                if fields_changed || content_changed || groups_changed {
                     if content_changed {
                         crate::state::edit_instance(
                             &instance.id,
@@ -216,12 +212,6 @@ pub(crate) async fn sync_direct_link_instances(
                         &mut tx,
                     )
                     .await?;
-                    instance_rows::replace_instance_groups(
-                        &instance.id,
-                        &groups,
-                        &mut tx,
-                    )
-                    .await?;
                     tx.commit().await?;
                     let _ = emit_instance(
                         &instance.id,

packages/app-lib/src/state/mod.rs

@@ -118,6 +118,7 @@ pub struct State {
     download_sample_requests: AtomicU64,
     download_sample_errors: AtomicU64,
     download_sample_throttles: AtomicU64,
+    download_sample_queue_waits: AtomicU64,
     pub(crate) install_job_semaphore: Semaphore,
     pub(crate) install_db_semaphore: Semaphore,
     pub(crate) install_job_cancellations: DashMap<Uuid, CancellationToken>,
@@ -196,6 +197,7 @@ struct AutoConcurrencySample {
     requests: u64,
     errors: u64,
     throttles: u64,
+    queue_waits: u64,
 }
 
 /// Per-instance lock registry with task-local reentrancy.
@@ -399,6 +401,15 @@ impl AutoConcurrencyController {
         } else {
             sample.errors as f64 / sample.requests as f64
         };
+        if sample.queue_waits > 0 {
+            self.high_utilization_windows = 0;
+            self.pressure_windows = 0;
+            self.probe = None;
+            self.cooldown_until = Some(now + AUTO_DOWNLOAD_PROBE_COOLDOWN);
+            return current
+                .saturating_sub(current.div_ceil(4))
+                .max(AUTO_DOWNLOAD_CONCURRENCY_MIN);
+        }
         // A single throttled window is handled by the per-host limiter; the
         // global concurrency only backs off when pressure persists across
         // several samples, and then in small steps instead of a big cut.
@@ -677,6 +688,11 @@ impl State {
         self.download_sample_errors.fetch_add(1, Ordering::AcqRel);
     }
 
+    pub(crate) fn record_download_queue_wait(&self) {
+        self.download_sample_queue_waits
+            .fetch_add(1, Ordering::AcqRel);
+    }
+
     pub(crate) fn update_download_settings(
         self: &Arc<Self>,
         settings: &Settings,
@@ -735,6 +751,7 @@ impl State {
                 self.download_sample_requests.swap(0, Ordering::AcqRel);
                 self.download_sample_errors.swap(0, Ordering::AcqRel);
                 self.download_sample_throttles.swap(0, Ordering::AcqRel);
+                self.download_sample_queue_waits.swap(0, Ordering::AcqRel);
                 continue;
             }
             let sample = AutoConcurrencySample {
@@ -749,6 +766,9 @@ impl State {
                 throttles: self
                     .download_sample_throttles
                     .swap(0, Ordering::AcqRel),
+                queue_waits: self
+                    .download_sample_queue_waits
+                    .swap(0, Ordering::AcqRel),
             };
             let current = self.download_concurrency();
             let ceiling =
@@ -771,6 +791,7 @@ impl State {
                     requests = sample.requests,
                     errors = sample.errors,
                     throttles = sample.throttles,
+                    queue_waits = sample.queue_waits,
                     "Adjusted automatic download concurrency"
                 );
                 self.resize_download_concurrency(target);
@@ -935,6 +956,7 @@ impl State {
             download_sample_requests: AtomicU64::new(0),
             download_sample_errors: AtomicU64::new(0),
             download_sample_throttles: AtomicU64::new(0),
+            download_sample_queue_waits: AtomicU64::new(0),
             install_job_semaphore: Semaphore::new(MAX_CONCURRENT_INSTALL_JOBS),
             install_db_semaphore: Semaphore::new(1),
             install_job_cancellations: DashMap::new(),
@@ -1024,6 +1046,7 @@ pub(crate) async fn test_state(
         download_sample_requests: AtomicU64::new(0),
         download_sample_errors: AtomicU64::new(0),
         download_sample_throttles: AtomicU64::new(0),
+        download_sample_queue_waits: AtomicU64::new(0),
         install_job_semaphore: Semaphore::new(1),
         install_db_semaphore: Semaphore::new(1),
         install_job_cancellations: DashMap::new(),
@@ -1053,9 +1076,24 @@ mod auto_concurrency_tests {
             requests: 100,
             errors: 0,
             throttles: 0,
+            queue_waits: 0,
         }
     }
 
+    #[test]
+    fn queue_pressure_backs_off_immediately_and_repeatedly() {
+        let mut controller = AutoConcurrencyController::default();
+        let now = Instant::now();
+        let congested = AutoConcurrencySample {
+            queue_waits: 1,
+            ..healthy(8, 100)
+        };
+
+        assert_eq!(controller.next_target(now, 128, 128, congested), 96);
+        assert_eq!(controller.next_target(now, 96, 128, congested), 72);
+        assert_eq!(controller.next_target(now, 16, 128, congested), 16);
+    }
+
     #[test]
     fn probes_up_after_two_saturated_windows_and_respects_ceiling() {
         let mut controller = AutoConcurrencyController::default();
@@ -1130,6 +1168,7 @@ mod auto_concurrency_tests {
             requests: 100,
             errors: 5,
             throttles: 0,
+            queue_waits: 0,
         };
         assert_eq!(controller.next_target(Instant::now(), 16, 128, sample), 16);
     }

packages/app-lib/src/util/download/h2_download.rs

@@ -62,6 +62,7 @@ pub(crate) enum H2DownloadOutcome {
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub(crate) enum H2DownloadFailure {
     Ineligible(&'static str),
+    Capacity,
     Connect,
     Tls,
     Protocol,
@@ -76,6 +77,7 @@ impl H2DownloadFailure {
     pub(crate) const fn as_str(self) -> &'static str {
         match self {
             Self::Ineligible(reason) => reason,
+            Self::Capacity => "HTTP/2 connection capacity is unavailable",
             Self::Connect => "HTTP/2 TCP connection failed",
             Self::Tls => "HTTP/2 TLS connection failed",
             Self::Protocol => "HTTP/2 protocol failed",
@@ -104,6 +106,7 @@ impl H2DownloadFailure {
 pub(crate) async fn try_download_via_h2(
     request: &DownloadRequest,
     route: &DownloadRoute,
+    semaphore: &fetch::FetchSemaphore,
     destination: &Path,
     part_path: &Path,
     policy: super::native::NativeH2Policy,
@@ -122,13 +125,19 @@ pub(crate) async fn try_download_via_h2(
             preserve_partial: false,
         };
     }
-    let connection = match connect_authority(
+    let connection_wait =
-        route,
+        connect_authority(route, true, policy.allow_cold_connection);
-        true,
+    let connection_result = if let Some(cancellation) =
-        policy.allow_cold_connection,
+        request.cancellation.as_ref()
-    )
-    .await
     {
+        tokio::select! {
+            _ = cancellation.cancelled() => return H2DownloadOutcome::Canceled,
+            result = connection_wait => result,
+        }
+    } else {
+        connection_wait.await
+    };
+    let connection = match connection_result {
         Ok(connection) => connection,
         Err(failure) => {
             return H2DownloadOutcome::Fallback {
@@ -137,6 +146,30 @@ pub(crate) async fn try_download_via_h2(
             };
         }
     };
+    // The shared connection reserves native capacity when it is created.
+    // Acquire the per-download permit afterwards so every native path uses
+    // the same native-then-fetch order and cannot form a circular wait.
+    let fetch_permit_wait =
+        fetch::acquire_fetch_permit_with_pressure(semaphore);
+    let fetch_permit_result = if let Some(cancellation) =
+        request.cancellation.as_ref()
+    {
+        tokio::select! {
+            _ = cancellation.cancelled() => return H2DownloadOutcome::Canceled,
+            result = fetch_permit_wait => result,
+        }
+    } else {
+        fetch_permit_wait.await
+    };
+    let _fetch_permit = match fetch_permit_result {
+        Ok(permit) => permit,
+        Err(_) => {
+            return H2DownloadOutcome::Fallback {
+                failure: H2DownloadFailure::Connect,
+                preserve_partial: false,
+            };
+        }
+    };
     let Ok(uri) = route.url.parse::<Uri>() else {
         return H2DownloadOutcome::Fallback {
             failure: H2DownloadFailure::Http,
@@ -156,14 +189,20 @@ pub(crate) async fn try_download_via_h2(
     let total_size = if let Some(size) = expected_size {
         size
     } else {
-        let _probe_stream_permit = match tokio::time::timeout(
+        let probe_wait = super::h2_stream_budget::acquire_with_pressure(route);
-            ASSET_RESOURCE_WAIT_TIMEOUT,
+        let probe_result = if let Some(cancellation) =
-            super::h2_stream_budget::acquire(route),
+            request.cancellation.as_ref()
-        )
-        .await
         {
-            Ok(Ok(permit)) => permit,
+            tokio::select! {
-            Ok(Err(_)) | Err(_) => {
+                _ = cancellation.cancelled() => return H2DownloadOutcome::Canceled,
+                result = probe_wait => result,
+            }
+        } else {
+            probe_wait.await
+        };
+        let _probe_stream_permit = match probe_result {
+            Ok(permit) => permit,
+            Err(_) => {
                 return H2DownloadOutcome::Fallback {
                     failure: H2DownloadFailure::Connect,
                     preserve_partial: false,
@@ -239,10 +278,7 @@ pub(crate) async fn try_download_via_h2(
         crate::install::DownloadItemStatus::WaitingForResource,
     )
     .await;
-    let stream_wait = tokio::time::timeout(
+    let stream_wait = super::h2_stream_budget::acquire_with_pressure(route);
-        ASSET_RESOURCE_WAIT_TIMEOUT,
-        super::h2_stream_budget::acquire(route),
-    );
     let stream_wait_started = Instant::now();
     let stream_result = if let Some(cancellation) =
         request.cancellation.as_ref()
@@ -255,8 +291,8 @@ pub(crate) async fn try_download_via_h2(
         stream_wait.await
     };
     let _stream_permit = match stream_result {
-        Ok(Ok(permit)) => permit,
+        Ok(permit) => permit,
-        Ok(Err(_)) | Err(_) => {
+        Err(_) => {
             return H2DownloadOutcome::Fallback {
                 failure: H2DownloadFailure::Connect,
                 preserve_partial: false,
@@ -327,6 +363,7 @@ async fn connect_authority(
                 "Failed to establish shared HTTP/2 connection"
             );
             Err(match error.kind {
+                H2ConnectFailureKind::Capacity => H2DownloadFailure::Capacity,
                 H2ConnectFailureKind::Tcp => H2DownloadFailure::Connect,
                 H2ConnectFailureKind::Tls => H2DownloadFailure::Tls,
                 H2ConnectFailureKind::Protocol => H2DownloadFailure::Protocol,
@@ -771,6 +808,12 @@ mod tests {
     use super::*;
     use bytes::Bytes;
 
+    #[test]
+    fn capacity_wait_is_not_classified_as_a_transport_failure() {
+        assert!(!H2DownloadFailure::Capacity.is_transfer_failure());
+        assert!(!H2DownloadFailure::Capacity.should_cooldown_authority());
+    }
+
     #[tokio::test]
     async fn single_stream_reports_bytes_before_the_response_finishes() {
         let size = 512 * 1024;
@@ -1183,28 +1226,6 @@ async fn download_asset_item(
             "timed out waiting for asset destination lock".to_string(),
         )
     })?;
-    let fetch_permit = if apply_native_policy {
-        let Some(semaphore) = native_semaphore else {
-            return Err(crate::ErrorKind::OtherError(
-                "native asset batch is missing fetch budget".to_string(),
-            )
-            .into());
-        };
-        Some(
-            tokio::time::timeout(
-                ASSET_RESOURCE_WAIT_TIMEOUT,
-                semaphore.0.acquire(),
-            )
-            .await
-            .map_err(|_| {
-                crate::ErrorKind::NetworkError(
-                    "timed out waiting for asset fetch permit".to_string(),
-                )
-            })??,
-        )
-    } else {
-        None
-    };
     // A different downloader may have committed the object while this item
     // waited for the destination lock. Reuse it instead of opening another
     // stream, which also prevents cross-engine `.part`/rename races.
@@ -1243,24 +1264,26 @@ async fn download_asset_item(
             return Ok(AssetBatchItemOutcome::LocalObjectFailed { error });
         }
     };
-    let _stream_permit = if apply_native_policy {
+    // Resolve the primary or lazily expanded sibling before taking the fetch
-        Some(
+    // permit. Shared connections reserve native capacity, so this preserves
-            tokio::time::timeout(
+    // the native-then-fetch order used by every other native path.
-                ASSET_RESOURCE_WAIT_TIMEOUT,
+    let connection = connections.connection(rescue).await;
-                super::h2_stream_budget::acquire_asset(route),
+    let fetch_permit = if apply_native_policy {
-            )
+        let Some(semaphore) = native_semaphore else {
-            .await
+            return Err(crate::ErrorKind::OtherError(
-            .map_err(|_| {
+                "native asset batch is missing fetch budget".to_string(),
-                crate::ErrorKind::NetworkError(
-                    "timed out waiting for asset HTTP/2 stream permit"
-                        .to_string(),
-                )
-            })??,
             )
+            .into());
+        };
+        Some(fetch::acquire_fetch_permit_with_pressure(semaphore).await?)
+    } else {
+        None
+    };
+    let _stream_permit = if apply_native_policy {
+        Some(super::h2_stream_budget::acquire_asset_with_pressure(route).await?)
     } else {
         None
     };
-    let connection = connections.connection(rescue).await;
     let _connection_stream = connection.track_stream();
     let mut headers = HeaderMap::new();
     headers.insert(

packages/app-lib/src/util/download/h2_pool.rs

@@ -34,6 +34,7 @@ const CONNECTION_WAIT_TIMEOUT: Duration = Duration::from_secs(45);
 
 #[derive(Debug, Clone, Copy, Eq, PartialEq)]
 pub(crate) enum H2ConnectFailureKind {
+    Capacity,
     Tcp,
     Tls,
     Protocol,
@@ -357,9 +358,41 @@ async fn connect_tcp(host: &str, port: u16) -> std::io::Result<TcpStream> {
 }
 
 /// Connects a new shared HTTP/2 connection to `authority` (host[:port]).
-async fn establish(
+async fn reserve_physical_budget(
     route: &DownloadRoute,
     reserve_native_budget: bool,
+) -> Result<Option<super::native_budget::NativeBudgetPermit>, H2ConnectError> {
+    Ok(if reserve_native_budget {
+        Some(
+            crate::util::fetch::wait_for_download_resource(
+                super::native_budget::acquire(route),
+            )
+            .await
+            .map_err(|_| {
+                H2ConnectError::new(
+                    H2ConnectFailureKind::Capacity,
+                    "HTTP/2 connection capacity remained stalled for 5 minutes"
+                        .to_string(),
+                )
+            })?
+            .map_err(|error| {
+                H2ConnectError::new(
+                    H2ConnectFailureKind::Capacity,
+                    format!(
+                        "failed to reserve HTTP/2 connection capacity: {error}"
+                    ),
+                )
+            })?,
+        )
+    } else {
+        None
+    })
+}
+
+/// Connects a new shared HTTP/2 connection to `authority` (host[:port]).
+async fn establish(
+    route: &DownloadRoute,
+    physical_budget: Option<super::native_budget::NativeBudgetPermit>,
 ) -> Result<Arc<SharedH2Connection>, H2ConnectError> {
     let authority =
         crate::util::fetch::url_authority(&route.url).ok_or_else(|| {
@@ -368,16 +401,6 @@ async fn establish(
                 "HTTP/2 route has no authority".to_string(),
             )
         })?;
-    let physical_budget = if reserve_native_budget {
-        Some(super::native_budget::acquire(route).await.map_err(|error| {
-            H2ConnectError::new(
-                H2ConnectFailureKind::Tcp,
-                format!("failed to reserve HTTP/2 connection capacity: {error}"),
-            )
-        })?)
-    } else {
-        None
-    };
     let (host, port) = authority
         .rsplit_once(':')
         .map(|(host, port)| (host, port.parse::<u16>().unwrap_or(443)))
@@ -487,14 +510,14 @@ pub(crate) async fn shared_connection(
             )
         })?;
     let slot = connection_slot(&authority).await;
-    let mut cached = tokio::time::timeout(CONNECTION_WAIT_TIMEOUT, slot.lock())
+    let mut cached = crate::util::fetch::wait_for_download_resource(
+        slot.lock(),
+    )
     .await
     .map_err(|_| {
         H2ConnectError::new(
-                H2ConnectFailureKind::Protocol,
+            H2ConnectFailureKind::Capacity,
-                format!(
+            format!("HTTP/2 connection slot remained stalled for {authority}"),
-                    "timed out waiting for HTTP/2 connection slot {authority}"
-                ),
         )
     })?;
     if let Some(connection) = cached.as_ref().filter(|connection| {
@@ -525,9 +548,11 @@ pub(crate) async fn shared_connection(
         ));
     }
     tracing::debug!(authority, "Establishing cold shared HTTP/2 connection");
+    let physical_budget =
+        reserve_physical_budget(route, reserve_native_budget).await?;
     let connection = tokio::time::timeout(
         CONNECTION_WAIT_TIMEOUT,
-        establish(route, reserve_native_budget),
+        establish(route, physical_budget),
     )
     .await
     .map_err(|_| {
@@ -555,15 +580,16 @@ pub(crate) async fn shared_batch_connection(
             )
         })?;
     let slot = batch_connection_slot(&authority).await;
-    let mut cached = tokio::time::timeout(
+    let mut cached = crate::util::fetch::wait_for_download_resource(
-        CONNECTION_WAIT_TIMEOUT,
         slot.lock(),
     )
     .await
     .map_err(|_| {
         H2ConnectError::new(
-            H2ConnectFailureKind::Protocol,
+            H2ConnectFailureKind::Capacity,
-            format!("timed out waiting for asset HTTP/2 connection slot {authority}"),
+            format!(
+                "asset HTTP/2 connection slot remained stalled for {authority}"
+            ),
         )
     })?;
     if let Some(connection) = cached.as_ref().filter(|connection| {
@@ -591,9 +617,11 @@ pub(crate) async fn shared_batch_connection(
         *cached = None;
     }
     tracing::debug!(authority, "Establishing sibling HTTP/2 asset connection");
+    let physical_budget =
+        reserve_physical_budget(route, reserve_native_budget).await?;
     let connection = tokio::time::timeout(
         CONNECTION_WAIT_TIMEOUT,
-        establish(route, reserve_native_budget),
+        establish(route, physical_budget),
     )
     .await
     .map_err(|_| {
@@ -614,10 +642,13 @@ pub(crate) async fn has_live_connection(authority: &str) -> bool {
         return false;
     };
     drop(connections);
-    let live = slot
+    let Ok(cached) = slot.try_lock() else {
-        .lock()
+        // This is only an eligibility probe. A busy slot means another task
-        .await
+        // is establishing or refreshing the connection; do not queue this
+        // caller behind that work before its cancellation-aware download path.
+        return false;
+    };
+    cached
         .as_ref()
-        .is_some_and(|connection| !connection.is_dead());
+        .is_some_and(|connection| !connection.is_dead())
-    live
 }

packages/app-lib/src/util/download/h2_range.rs

@@ -218,12 +218,8 @@ async fn download_range(
         crate::install::DownloadItemStatus::WaitingForResource,
     )
     .await;
-    let _permit = tokio::time::timeout(
+    let _permit = super::h2_stream_budget::acquire_with_pressure(route)
-        Duration::from_secs(45),
-        super::h2_stream_budget::acquire(route),
-    )
         .await
-    .map_err(|_| H2DownloadFailure::Connect)?
         .map_err(|_| H2DownloadFailure::Connect)?;
     super::h2_download::record_install_stage(
         request,

packages/app-lib/src/util/download/h2_stream_budget.rs

@@ -104,6 +104,20 @@ pub(crate) async fn acquire(
     }
 }
 
+pub(crate) async fn acquire_with_pressure(
+    route: &DownloadRoute,
+) -> crate::Result<H2StreamPermit> {
+    crate::util::fetch::wait_for_download_resource(acquire(route))
+        .await
+        .map_err(|_| {
+            crate::Error::from(crate::ErrorKind::NetworkError(
+                "HTTP/2 stream permit remained stalled for 5 minutes"
+                    .to_string(),
+            ))
+        })?
+        .map_err(Into::into)
+}
+
 /// Acquires a stream for the Minecraft asset batch. Assets retain a large
 /// logical worker window, but use a separate physical stream pool so they
 /// cannot consume the ordinary native content share.
@@ -134,10 +148,25 @@ pub(crate) async fn acquire_asset(
     }
 }
 
+pub(crate) async fn acquire_asset_with_pressure(
+    route: &DownloadRoute,
+) -> crate::Result<H2StreamPermit> {
+    crate::util::fetch::wait_for_download_resource(acquire_asset(route))
+        .await
+        .map_err(|_| {
+            crate::Error::from(crate::ErrorKind::NetworkError(
+                "asset HTTP/2 stream permit remained stalled for 5 minutes"
+                    .to_string(),
+            ))
+        })?
+        .map_err(Into::into)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
     use crate::util::fetch::DownloadRouteSource;
+    use std::sync::atomic::{AtomicUsize, Ordering};
 
     fn route() -> DownloadRoute {
         DownloadRoute {
@@ -190,4 +219,40 @@ mod tests {
             MAX_H2_STREAMS_PER_AUTHORITY
         );
     }
+
+    #[tokio::test]
+    async fn contended_stream_wait_reports_pressure_and_resumes() {
+        let route = DownloadRoute {
+            url: "https://h2-pressure.example/file".to_string(),
+            source: DownloadRouteSource::Official,
+            is_mirror: false,
+            allow_sensitive_headers: true,
+            supports_range: true,
+            proxy: ProxyPolicy::Direct,
+        };
+        let mut held = Vec::new();
+        for _ in 0..MAX_H2_STREAMS_PER_AUTHORITY {
+            held.push(acquire(&route).await.unwrap());
+        }
+        let pressure = Arc::new(AtomicUsize::new(0));
+        let observed = Arc::clone(&pressure);
+        let release = tokio::spawn(async move {
+            tokio::time::sleep(Duration::from_millis(35)).await;
+            drop(held);
+        });
+
+        let permit = crate::util::fetch::wait_for_resource_with_pressure(
+            acquire(&route),
+            Duration::from_millis(5),
+            Duration::from_millis(100),
+            move || {
+                observed.fetch_add(1, Ordering::Relaxed);
+            },
+        )
+        .await;
+
+        release.await.unwrap();
+        assert!(permit.is_ok());
+        assert!(pressure.load(Ordering::Relaxed) >= 1);
+    }
 }

packages/app-lib/src/util/download/mod.rs

@@ -73,6 +73,19 @@ pub(crate) fn task_concurrency_limit(state: &crate::State) -> Option<usize> {
     if active_engine() == DownloadEngine::XmclCompat {
         None
     } else {
-        Some(state.download_concurrency())
+        Some(native_budget::task_limit(
+            state.download_concurrency(),
+            usize::MAX,
+        ))
+    }
+}
+
+pub(crate) fn single_authority_task_concurrency_limit(
+    state: &crate::State,
+) -> Option<usize> {
+    if active_engine() == DownloadEngine::XmclCompat {
+        None
+    } else {
+        Some(native_budget::task_limit(state.download_concurrency(), 1))
     }
 }

packages/app-lib/src/util/download/native_budget.rs

@@ -144,6 +144,15 @@ pub(crate) fn available(route: &DownloadRoute) -> usize {
         .unwrap_or(MAX_CONNECTIONS_PER_AUTHORITY)
 }
 
+pub(crate) fn task_limit(
+    configured_limit: usize,
+    authority_count: usize,
+) -> usize {
+    configured_limit.max(1).min(MAX_NATIVE_CONNECTIONS).min(
+        MAX_CONNECTIONS_PER_AUTHORITY.saturating_mul(authority_count.max(1)),
+    )
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -174,4 +183,11 @@ mod tests {
         drop(permits);
         assert!(try_acquire(&route).is_ok());
     }
+
+    #[test]
+    fn task_limit_matches_native_connection_capacity() {
+        assert_eq!(task_limit(128, 1), 8);
+        assert_eq!(task_limit(128, 4), 32);
+        assert_eq!(task_limit(4, 1), 4);
+    }
 }

packages/app-lib/src/util/fetch.rs

@@ -85,6 +85,8 @@ const MAX_REDIRECT_LOCATION_BYTES: usize = 8 * 1024;
 const FILE_TRANSFER_CONNECT_TIMEOUT: time::Duration =
     time::Duration::from_secs(20);
 const RESOURCE_WAIT_TIMEOUT: time::Duration = time::Duration::from_secs(45);
+const RESOURCE_PRESSURE_INTERVAL: time::Duration = time::Duration::from_secs(3);
+const RESOURCE_STALL_TIMEOUT: time::Duration = time::Duration::from_secs(300);
 #[cfg(not(test))]
 const FILE_TRANSFER_READ_TIMEOUT: time::Duration =
     time::Duration::from_secs(60);
@@ -3894,6 +3896,73 @@ struct NativeConnectionPermit<'a> {
     _native: crate::util::download::native_budget::NativeBudgetPermit,
 }
 
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub(crate) enum ResourceWaitError {
+    TimedOut,
+}
+
+pub(crate) async fn wait_for_resource_with_pressure<F, T, P>(
+    future: F,
+    pressure_interval: time::Duration,
+    stall_timeout: time::Duration,
+    mut on_pressure: P,
+) -> Result<T, ResourceWaitError>
+where
+    F: Future<Output = T>,
+    P: FnMut(),
+{
+    let pressure_interval =
+        pressure_interval.max(time::Duration::from_millis(1));
+    let pressure_timer = tokio::time::sleep(pressure_interval);
+    let stall_timer = tokio::time::sleep(stall_timeout);
+    tokio::pin!(future, pressure_timer, stall_timer);
+
+    loop {
+        tokio::select! {
+            result = &mut future => return Ok(result),
+            _ = &mut stall_timer => return Err(ResourceWaitError::TimedOut),
+            _ = &mut pressure_timer => {
+                on_pressure();
+                pressure_timer.as_mut().reset(
+                    tokio::time::Instant::now() + pressure_interval,
+                );
+            }
+        }
+    }
+}
+
+pub(crate) async fn wait_for_download_resource<F, T>(
+    future: F,
+) -> Result<T, ResourceWaitError>
+where
+    F: Future<Output = T>,
+{
+    wait_for_resource_with_pressure(
+        future,
+        RESOURCE_PRESSURE_INTERVAL,
+        RESOURCE_STALL_TIMEOUT,
+        || {
+            if let Some(state) = crate::State::get_if_initialized() {
+                state.record_download_queue_wait();
+            }
+        },
+    )
+    .await
+}
+
+pub(crate) async fn acquire_fetch_permit_with_pressure(
+    semaphore: &FetchSemaphore,
+) -> crate::Result<SemaphorePermit<'_>> {
+    wait_for_download_resource(semaphore.0.acquire())
+        .await
+        .map_err(|_| {
+            crate::Error::from(ErrorKind::NetworkError(
+                "download permit remained stalled for 5 minutes".to_string(),
+            ))
+        })?
+        .map_err(Into::into)
+}
+
 async fn acquire_native_connection<'a>(
     route: &DownloadRoute,
     semaphore: &'a FetchSemaphore,
@@ -3906,6 +3975,20 @@ async fn acquire_native_connection<'a>(
     })
 }
 
+async fn acquire_native_connection_with_pressure<'a>(
+    route: &DownloadRoute,
+    semaphore: &'a FetchSemaphore,
+) -> crate::Result<NativeConnectionPermit<'a>> {
+    wait_for_download_resource(acquire_native_connection(route, semaphore))
+        .await
+        .map_err(|_| {
+            crate::Error::from(ErrorKind::NetworkError(
+                "native download resources remained stalled for 5 minutes"
+                    .to_string(),
+            ))
+        })?
+}
+
 fn try_acquire_native_connection<'a>(
     route: &DownloadRoute,
     semaphore: &'a FetchSemaphore,
@@ -5703,19 +5786,11 @@ async fn download_to_path_inner(
         None
     };
     if let Some((h2_route, h2_policy)) = h2_selection {
-        let h2_permit =
-            tokio::time::timeout(RESOURCE_WAIT_TIMEOUT, semaphore.0.acquire())
-                .await
-                .map_err(|_| {
-                    ErrorKind::NetworkError(
-                        "timed out waiting for HTTP/2 download permit"
-                            .to_string(),
-                    )
-                })??;
         let h2_started = Instant::now();
         match crate::util::download::h2_download::try_download_via_h2(
             &request,
             &h2_route,
+            semaphore,
             destination,
             &part_path,
             h2_policy,
@@ -5808,7 +5883,6 @@ async fn download_to_path_inner(
                     .await?;
             }
         }
-        drop(h2_permit);
     }
 
     let mut official_integrity_retry = h2_failed_nonofficial.is_some();
@@ -6147,8 +6221,6 @@ async fn download_to_path_inner(
                 } else {
                     0
                 };
-                let mut activity = crate::State::get_if_initialized()
-                    .map(|state| state.begin_download_connection());
                 record_install_download_started(
                     &request,
                     route,
@@ -6161,25 +6233,21 @@ async fn download_to_path_inner(
                     DownloadItemStatus::WaitingForResource,
                 )
                 .await;
-                let permit_wait = tokio::time::timeout(
+                let permit_wait =
-                    RESOURCE_WAIT_TIMEOUT,
+                    acquire_native_connection_with_pressure(route, semaphore);
-                    acquire_native_connection(route, semaphore),
-                );
                 let resource_wait_started = Instant::now();
-                let permit = if let Some(cancellation) = request.cancellation.as_ref() {
+                let permit = if let Some(cancellation) =
+                    request.cancellation.as_ref()
+                {
                     tokio::select! {
                         _ = cancellation.cancelled() => return Err(ErrorKind::OtherError("download canceled while waiting for native resources".to_string()).into()),
                         result = permit_wait => result,
                     }
                 } else {
                     permit_wait.await
-                }
+                }?;
-                .map_err(|_| {
+                let mut activity = crate::State::get_if_initialized()
-                    ErrorKind::NetworkError(
+                    .map(|state| state.begin_download_connection());
-                        "timed out waiting for native download resources"
-                            .to_string(),
-                    )
-                })??;
                 tracing::debug!(
                     route = %sanitize_url_for_log(&route.url),
                     resource = "native_connection_and_fetch",
@@ -7135,6 +7203,40 @@ mod tests {
     static H2_FALLBACK_TEST_LOCK: LazyLock<std::sync::Mutex<()>> =
         LazyLock::new(|| std::sync::Mutex::new(()));
 
+    #[tokio::test]
+    async fn resource_wait_reports_pressure_without_losing_queue_position() {
+        let pressure_events = Arc::new(AtomicUsize::new(0));
+        let observed = Arc::clone(&pressure_events);
+        let result = wait_for_resource_with_pressure(
+            async {
+                tokio::time::sleep(Duration::from_millis(35)).await;
+                7
+            },
+            Duration::from_millis(5),
+            Duration::from_millis(100),
+            move || {
+                observed.fetch_add(1, Ordering::Relaxed);
+            },
+        )
+        .await;
+
+        assert_eq!(result, Ok(7));
+        assert!(pressure_events.load(Ordering::Relaxed) >= 1);
+    }
+
+    #[tokio::test]
+    async fn resource_wait_keeps_a_final_stall_guard() {
+        let result = wait_for_resource_with_pressure(
+            std::future::pending::<()>(),
+            Duration::from_millis(5),
+            Duration::from_millis(25),
+            || {},
+        )
+        .await;
+
+        assert_eq!(result, Err(ResourceWaitError::TimedOut));
+    }
+
     async fn spawn_range_server(
         data: Arc<Vec<u8>>,
         wrong_content_range: bool,