Silence clippies, minor doc fix (#2543)

* doc: remove stray backtick

* chore: clippy::let_unit_value

* chore: silence useless_transmute, duplicate_mod

* chore: remove allowing deref_nullptr

not needed since bindgen 0.60.0.

* chore: remove repeated allowed lints

they are already allowed from the crate root.

docs/sourcetree.md

@@ -96,7 +96,7 @@ A single virtual environment with all dependencies is described in the single `P
       sudo apt install python3.9
       ```
 - Install `poetry`
-    - Exact version of `poetry` is not important, see installation instructions available at poetry's [website](https://python-poetry.org/docs/#installation)`.
+    - Exact version of `poetry` is not important, see installation instructions available at poetry's [website](https://python-poetry.org/docs/#installation).
 - Install dependencies via `./scripts/pysync`.
     - Note that CI uses specific Python version (look for `PYTHON_VERSION` [here](https://github.com/neondatabase/docker-images/blob/main/rust/Dockerfile))
       so if you have different version some linting tools can yield different result locally vs in the CI.

libs/postgres_ffi/src/lib.rs

@@ -3,9 +3,11 @@
 #![allow(non_snake_case)]
 // bindgen creates some unsafe code with no doc comments.
 #![allow(clippy::missing_safety_doc)]
-// suppress warnings on rust 1.53 due to bindgen unit tests.
-// https://github.com/rust-lang/rust-bindgen/issues/1651
-#![allow(deref_nullptr)]
+// noted at 1.63 that in many cases there's a u32 -> u32 transmutes in bindgen code.
+#![allow(clippy::useless_transmute)]
+// modules included with the postgres_ffi macro depend on the types of the specific version's
+// types, and trigger a too eager lint.
+#![allow(clippy::duplicate_mod)]
 
 use bytes::Bytes;
 use utils::bin_ser::SerializeError;

libs/postgres_ffi/src/xlog_utils.rs

@@ -57,12 +57,10 @@ pub const SIZE_OF_XLOG_RECORD_DATA_HEADER_SHORT: usize = 1 * 2;
 /// in order to let CLOG_TRUNCATE mechanism correctly extend CLOG.
 const XID_CHECKPOINT_INTERVAL: u32 = 1024;
 
-#[allow(non_snake_case)]
 pub fn XLogSegmentsPerXLogId(wal_segsz_bytes: usize) -> XLogSegNo {
     (0x100000000u64 / wal_segsz_bytes as u64) as XLogSegNo
 }
 
-#[allow(non_snake_case)]
 pub fn XLogSegNoOffsetToRecPtr(
     segno: XLogSegNo,
     offset: u32,
@@ -71,7 +69,6 @@ pub fn XLogSegNoOffsetToRecPtr(
     segno * (wal_segsz_bytes as u64) + (offset as u64)
 }
 
-#[allow(non_snake_case)]
 pub fn XLogFileName(tli: TimeLineID, logSegNo: XLogSegNo, wal_segsz_bytes: usize) -> String {
     format!(
         "{:>08X}{:>08X}{:>08X}",
@@ -81,7 +78,6 @@ pub fn XLogFileName(tli: TimeLineID, logSegNo: XLogSegNo, wal_segsz_bytes: usize
     )
 }
 
-#[allow(non_snake_case)]
 pub fn XLogFromFileName(fname: &str, wal_seg_size: usize) -> (XLogSegNo, TimeLineID) {
     let tli = u32::from_str_radix(&fname[0..8], 16).unwrap();
     let log = u32::from_str_radix(&fname[8..16], 16).unwrap() as XLogSegNo;
@@ -89,12 +85,10 @@ pub fn XLogFromFileName(fname: &str, wal_seg_size: usize) -> (XLogSegNo, TimeLin
     (log * XLogSegmentsPerXLogId(wal_seg_size) + seg, tli)
 }
 
-#[allow(non_snake_case)]
 pub fn IsXLogFileName(fname: &str) -> bool {
     return fname.len() == XLOG_FNAME_LEN && fname.chars().all(|c| c.is_ascii_hexdigit());
 }
 
-#[allow(non_snake_case)]
 pub fn IsPartialXLogFileName(fname: &str) -> bool {
     fname.ends_with(".partial") && IsXLogFileName(&fname[0..fname.len() - 8])
 }

pageserver/src/tenant/timeline.rs

@@ -627,7 +627,7 @@ impl Timeline {
             .unwrap_or(self.conf.default_tenant_conf.max_lsn_wal_lag);
         drop(tenant_conf_guard);
         let self_clone = Arc::clone(self);
-        let _ = spawn_connection_manager_task(
+        spawn_connection_manager_task(
             self.conf.broker_etcd_prefix.clone(),
             self_clone,
             walreceiver_connect_timeout,

proxy/src/cancellation.rs

@@ -129,13 +129,13 @@ mod tests {
             assert!(CANCEL_MAP.contains(&session));
 
             tx.send(()).expect("failed to send");
-            let () = futures::future::pending().await; // sleep forever
+            futures::future::pending::<()>().await; // sleep forever
 
             Ok(())
         }));
 
         // Wait until the task has been spawned.
-        let () = rx.await.context("failed to hear from the task")?;
+        rx.await.context("failed to hear from the task")?;
 
         // Drop the session's entry by cancelling the task.
         task.abort();