Update rust to 1.86.0 (#11431)

We keep the practice of keeping the compiler up to date, pointing to the
latest release. This is done by many other projects in the Rust
ecosystem as well.

[Announcement blog
post](https://blog.rust-lang.org/2025/04/03/Rust-1.86.0.html).

Prior update was in #10914.

build-tools.Dockerfile

@@ -292,7 +292,7 @@ WORKDIR /home/nonroot
 
 # Rust
 # Please keep the version of llvm (installed above) in sync with rust llvm (`rustc --version --verbose | grep LLVM`)
-ENV RUSTC_VERSION=1.85.0
+ENV RUSTC_VERSION=1.86.0
 ENV RUSTUP_HOME="/home/nonroot/.rustup"
 ENV PATH="/home/nonroot/.cargo/bin:${PATH}"
 ARG RUSTFILT_VERSION=0.2.1

compute_tools/src/spec_apply.rs

@@ -419,7 +419,7 @@ impl ComputeNode {
                 .iter()
                 .filter_map(|val| val.parse::<usize>().ok())
                 .map(|val| if val > 1 { val - 1 } else { 1 })
-                .last()
+                .next_back()
                 .unwrap_or(3)
         }
     }

libs/remote_storage/tests/test_real_s3.rs

@@ -558,7 +558,7 @@ async fn upload_large_enough_file(
 ) -> usize {
     let header = bytes::Bytes::from_static("remote blob data content".as_bytes());
     let body = bytes::Bytes::from(vec![0u8; 1024]);
-    let contents = std::iter::once(header).chain(std::iter::repeat(body).take(128));
+    let contents = std::iter::once(header).chain(std::iter::repeat_n(body, 128));
 
     let len = contents.clone().fold(0, |acc, next| acc + next.len());
 

pageserver/src/task_mgr.rs

@@ -219,8 +219,7 @@ pageserver_runtime!(MGMT_REQUEST_RUNTIME, "mgmt request worker");
 pageserver_runtime!(WALRECEIVER_RUNTIME, "walreceiver worker");
 pageserver_runtime!(BACKGROUND_RUNTIME, "background op worker");
 // Bump this number when adding a new pageserver_runtime!
-// SAFETY: it's obviously correct
-const NUM_MULTIPLE_RUNTIMES: NonZeroUsize = unsafe { NonZeroUsize::new_unchecked(4) };
+const NUM_MULTIPLE_RUNTIMES: NonZeroUsize = NonZeroUsize::new(4).unwrap();
 
 #[derive(Debug, Clone, Copy)]
 pub struct PageserverTaskId(u64);

pageserver/src/tenant.rs

@@ -3689,7 +3689,7 @@ impl Tenant {
                         }
                     }
                 }
-                TenantState::Active { .. } => {
+                TenantState::Active => {
                     return Ok(());
                 }
                 TenantState::Broken { reason, .. } => {

pageserver/src/tenant/layer_map/layer_coverage.rs

@@ -53,7 +53,7 @@ impl<Value: Clone> LayerCoverage<Value> {
     ///
     /// Complexity: O(log N)
     fn add_node(&mut self, key: i128) {
-        let value = match self.nodes.range(..=key).last() {
+        let value = match self.nodes.range(..=key).next_back() {
             Some((_, Some(v))) => Some(v.clone()),
             Some((_, None)) => None,
             None => None,

pageserver/src/tenant/mgr.rs

@@ -58,7 +58,7 @@ use crate::{InitializationOrder, TEMP_FILE_SUFFIX};
 
 /// For a tenant that appears in TenantsMap, it may either be
 /// - `Attached`: has a full Tenant object, is elegible to service
-///    reads and ingest WAL.
+///   reads and ingest WAL.
 /// - `Secondary`: is only keeping a local cache warm.
 ///
 /// Secondary is a totally distinct state rather than being a mode of a `Tenant`, because

pageserver/src/tenant/remote_timeline_client/index.rs

@@ -130,7 +130,7 @@ impl IndexPart {
     /// Version history
     /// - 2: added `deleted_at`
     /// - 3: no longer deserialize `timeline_layers` (serialized format is the same, but timeline_layers
-    ///      is always generated from the keys of `layer_metadata`)
+    ///   is always generated from the keys of `layer_metadata`)
     /// - 4: timeline_layers is fully removed.
     /// - 5: lineage was added
     /// - 6: last_aux_file_policy is added.

pageserver/src/tenant/timeline.rs

@@ -2247,7 +2247,7 @@ impl Timeline {
                         .await
                         .expect("holding a reference to self");
                 }
-                TimelineState::Active { .. } => {
+                TimelineState::Active => {
                     return Ok(());
                 }
                 TimelineState::Broken { .. } | TimelineState::Stopping => {

pageserver/src/virtual_file/owned_buffers_io/aligned_buffer/buffer_mut.rs

@@ -25,8 +25,8 @@ impl<const A: usize> AlignedBufferMut<ConstAlign<A>> {
     /// * `align` must be a power of two,
     ///
     /// * `capacity`, when rounded up to the nearest multiple of `align`,
-    ///    must not overflow isize (i.e., the rounded value must be
-    ///    less than or equal to `isize::MAX`).
+    ///   must not overflow isize (i.e., the rounded value must be
+    ///   less than or equal to `isize::MAX`).
     pub fn with_capacity(capacity: usize) -> Self {
         AlignedBufferMut {
             raw: RawAlignedBuffer::with_capacity(capacity),

pageserver/src/virtual_file/owned_buffers_io/aligned_buffer/raw.rs

@@ -37,8 +37,8 @@ impl<const A: usize> RawAlignedBuffer<ConstAlign<A>> {
     /// * `align` must be a power of two,
     ///
     /// * `capacity`, when rounded up to the nearest multiple of `align`,
-    ///    must not overflow isize (i.e., the rounded value must be
-    ///    less than or equal to `isize::MAX`).
+    ///   must not overflow isize (i.e., the rounded value must be
+    ///   less than or equal to `isize::MAX`).
     pub fn with_capacity(capacity: usize) -> Self {
         let align = ConstAlign::<A>;
         let layout = Layout::from_size_align(capacity, align.align()).expect("Invalid layout");

rust-toolchain.toml

@@ -1,5 +1,5 @@
 [toolchain]
-channel = "1.85.0"
+channel = "1.86.0"
 profile = "default"
 # The default profile includes rustc, rust-std, cargo, rust-docs, rustfmt and clippy.
 # https://rust-lang.github.io/rustup/concepts/profiles.html

safekeeper/src/receive_wal.rs

@@ -94,10 +94,10 @@ impl WalReceivers {
 
     /// Get reference to locked slot contents. Slot must exist (registered
     /// earlier).
-    fn get_slot<'a>(
-        self: &'a Arc<WalReceivers>,
+    fn get_slot(
+        self: &Arc<WalReceivers>,
         id: WalReceiverId,
-    ) -> MappedMutexGuard<'a, WalReceiverState> {
+    ) -> MappedMutexGuard<'_, WalReceiverState> {
         MutexGuard::map(self.mutex.lock(), |locked| {
             locked.slots[id]
                 .as_mut()

safekeeper/src/timeline.rs

@@ -699,7 +699,7 @@ impl Timeline {
     }
 
     /// Take a writing mutual exclusive lock on timeline shared_state.
-    pub async fn write_shared_state<'a>(self: &'a Arc<Self>) -> WriteGuardSharedState<'a> {
+    pub async fn write_shared_state(self: &Arc<Self>) -> WriteGuardSharedState<'_> {
         WriteGuardSharedState::new(self.clone(), self.mutex.write().await)
     }
 

safekeeper/tests/misc_test.rs

@@ -116,7 +116,7 @@ fn test_many_tx() -> anyhow::Result<()> {
             }
             None
         })
-        .last()
+        .next_back()
         .unwrap();
 
     let initdb_lsn = 21623024;

storage_controller/src/heartbeater.rs

@@ -253,7 +253,7 @@ impl HeartBeat<Node, PageserverState> for HeartbeaterTask<Node, PageserverState>
                 PageserverState::WarmingUp { .. } => {
                     warming_up += 1;
                 }
-                PageserverState::Offline { .. } => offline += 1,
+                PageserverState::Offline => offline += 1,
                 PageserverState::Available { .. } => {}
             }
         }
@@ -391,7 +391,7 @@ impl HeartBeat<Safekeeper, SafekeeperState> for HeartbeaterTask<Safekeeper, Safe
         let mut offline = 0;
         for state in new_state.values() {
             match state {
-                SafekeeperState::Offline { .. } => offline += 1,
+                SafekeeperState::Offline => offline += 1,
                 SafekeeperState::Available { .. } => {}
             }
         }

storage_controller/src/main.rs

@@ -283,10 +283,8 @@ impl Secrets {
     fn load_secret(cli: &Option<String>, env_name: &str) -> Option<String> {
         if let Some(v) = cli {
             Some(v.clone())
-        } else if let Ok(v) = std::env::var(env_name) {
-            Some(v)
         } else {
-            None
+            std::env::var(env_name).ok()
         }
     }
 }

storage_controller/src/tenant_shard.rs

@@ -622,7 +622,7 @@ impl TenantShard {
             .collect::<Vec<_>>();
 
         attached_locs.sort_by_key(|i| i.1);
-        if let Some((node_id, _gen)) = attached_locs.into_iter().last() {
+        if let Some((node_id, _gen)) = attached_locs.into_iter().next_back() {
             self.intent.set_attached(scheduler, Some(*node_id));
         }
 

storage_scrubber/src/find_large_objects.rs

@@ -18,7 +18,7 @@ enum LargeObjectKind {
 
 impl LargeObjectKind {
     fn from_key(key: &str) -> Self {
-        let fname = key.split('/').last().unwrap();
+        let fname = key.split('/').next_back().unwrap();
 
         let Ok((layer_name, _generation)) = parse_layer_object_name(fname) else {
             return LargeObjectKind::Other;