refactor(lading): drop expect_used quarantines and annotate bins

Annotate the lading bin entry points (lading, captool, payloadtool),
drop the `#![allow(clippy::expect_used)]` quarantine from lib.rs and
the three bin entrypoints, and annotate previously-masked production
sites in process_tree, tcp_rr, and udp generators that the quarantine
drop surfaces.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: goxberry

lading/src/bin/captool/main.rs

@@ -1,9 +1,6 @@
 //! Capture analysis tool for lading capture files.
 
 #![expect(clippy::print_stdout)]
-// Quarantine: workspace denies `clippy::expect_used`, but this binary still has
-// production `.expect()` sites awaiting cleanup. Remove once cleaned up.
-#![allow(clippy::expect_used)]
 
 mod analyze;
 
@@ -75,6 +72,10 @@ pub enum Error {
 
 #[tokio::main(flavor = "current_thread")]
 #[expect(clippy::too_many_lines)]
+#[expect(
+    clippy::expect_used,
+    reason = "FIXME: line read and JSON deserialization should surface as Error variants rather than panicking; tracked for follow-up. Task join panics are intentional propagation of inner panics."
+)]
 async fn main() -> Result<(), Error> {
     tracing_subscriber::fmt()
         .with_span_events(FmtSpan::FULL)
@@ -230,6 +231,10 @@ async fn main() -> Result<(), Error> {
     Ok(())
 }
 
+#[expect(
+    clippy::expect_used,
+    reason = "FIXME: line read and JSON deserialization should surface as Error variants rather than panicking; tracked for follow-up. Task join panics are intentional propagation of inner panics."
+)]
 async fn validate_capture(capture_path_str: &str, min_seconds: Option<u64>) -> Result<(), Error> {
     let capture_path = path::Path::new(capture_path_str);
     if !capture_path.exists() {
@@ -286,6 +291,10 @@ async fn validate_capture(capture_path_str: &str, min_seconds: Option<u64>) -> R
     report_validation_result(&result, min_seconds)
 }
 
+#[expect(
+    clippy::expect_used,
+    reason = "ValidationResult::first_error is Some whenever is_valid() returns false; the unreachable None branch indicates a programming error in the validator"
+)]
 fn report_validation_result(
     result: &lading_capture::validate::ValidationResult,
     min_seconds: Option<u64>,

lading/src/bin/lading.rs

@@ -1,9 +1,5 @@
 //! Main lading binary for load testing.
 
-// Quarantine: workspace denies `clippy::expect_used`, but this binary still has
-// production `.expect()` sites awaiting cleanup. Remove once cleaned up.
-#![allow(clippy::expect_used)]
-
 use std::{
     env,
     fmt::{self, Display},
@@ -105,6 +101,10 @@ impl Display for CliKeyValues {
 impl FromStr for CliKeyValues {
     type Err = String;
 
+    #[expect(
+        clippy::expect_used,
+        reason = "compile-time-constant regex literal; capture group 0 always exists on a successful match"
+    )]
     fn from_str(input: &str) -> Result<Self, Self::Err> {
         // A key matches `[[:alnum:]_-]+` (letters, digits, underscores,
         // hyphens) and a value conforms to `[[:alpha:]_:,`. A key is always
@@ -307,6 +307,10 @@ fn validate_config(config_path: &str) -> Result<Config, Error> {
     }
 }
 
+#[expect(
+    clippy::expect_used,
+    reason = "PIDs from --target-pid CLI argument fit in i32 on supported platforms; a failure indicates a platform invariant violation"
+)]
 fn get_config(args: &LadingArgs, config: Option<String>) -> Result<Config, Error> {
     let mut config = if let Some(contents) = config {
         // Config provided via environment variable - parse as single file
@@ -401,6 +405,10 @@ fn get_config(args: &LadingArgs, config: Option<String>) -> Result<Config, Error
 }
 
 #[expect(clippy::too_many_lines)]
+#[expect(
+    clippy::expect_used,
+    reason = "telemetry is validated in get_config before reaching inner_main; the metrics recorder and capture manager are global singletons whose set-once installation is part of the documented startup contract"
+)]
 async fn inner_main(
     experiment_duration: Duration,
     warmup_duration: Duration,

lading/src/bin/payloadtool.rs

@@ -2,9 +2,6 @@
 
 #![expect(clippy::print_stdout)]
 #![expect(clippy::print_stderr)]
-// Quarantine: workspace denies `clippy::expect_used`, but this binary still has
-// production `.expect()` sites awaiting cleanup. Remove once cleaned up.
-#![allow(clippy::expect_used)]
 
 /// Memory allocation tracking for payloadtool statistics.
 ///
@@ -284,6 +281,10 @@ struct Args {
     dump: Option<PathBuf>,
 }
 
+#[expect(
+    clippy::expect_used,
+    reason = "Byte::from_u128 only fails on 0; total_bytes is NonZeroU32, and the diagnostic-path total_generated_bytes path inherits the same invariant from the caller"
+)]
 fn generate_and_check(
     config: &lading_payload::Config,
     seed: [u8; 32],
@@ -367,6 +368,10 @@ fn generate_and_check(
 }
 
 #[expect(clippy::too_many_lines)]
+#[expect(
+    clippy::expect_used,
+    reason = "FIXME: maximum_prebuild_cache_size_bytes is user-supplied config; a zero value should surface as a recoverable error rather than panicking. Tracked for follow-up."
+)]
 fn check_generator(config: &generator::Config, args: &Args) -> Result<Option<Fingerprint>> {
     match &config.inner {
         generator::Inner::FileGen(g) => {

lading/src/generator/process_tree.rs

@@ -441,6 +441,10 @@ impl Process {
 ///
 /// Function will panic if the process execution fails.
 ///
+#[expect(
+    clippy::expect_used,
+    reason = "the iterator is populated from the caller's pre-validated process tree; missing nodes or missing exit codes indicate a programming error in the tree construction"
+)]
 pub fn spawn_tree(nodes: &VecDeque<Process>, sleep_ns: u32) -> Result<(), Error> {
     let mut iter = nodes.iter().peekable();
     let mut pids_to_wait: FxHashSet<Pid> = FxHashSet::default();

lading/src/generator/tcp_rr.rs

@@ -128,6 +128,10 @@ impl TcpRr {
     /// # Panics
     ///
     /// Panics if `addr` cannot be resolved to a socket address.
+    #[expect(
+        clippy::expect_used,
+        reason = "FIXME: config.addr is user-supplied; parse failure should surface as an Error variant instead of panicking. Tracked for follow-up."
+    )]
     pub async fn spin(self) -> Result<(), Error> {
         if self.config.threads > self.config.flows {
             return Err(Error::Config(format!(
@@ -233,6 +237,10 @@ impl TcpRr {
     }
 }
 
+#[expect(
+    clippy::expect_used,
+    reason = "mio Poll creation, nonblocking setup, and registry registration fail only on system resource exhaustion; documented contract for the per-thread client startup"
+)]
 fn client_thread_main(
     addr: SocketAddr,
     num_flows: u16,

lading/src/generator/udp.rs

@@ -142,6 +142,10 @@ impl Udp {
     /// Function will panic if user has passed zero values for any byte
     /// values. Sharp corners.
     #[expect(clippy::cast_possible_truncation)]
+    #[expect(
+        clippy::expect_used,
+        reason = "FIXME: config.addr is user-supplied; socket address parsing failures should surface as Error variants instead of panicking. Tracked for follow-up."
+    )]
     pub fn new(
         general: General,
         config: &Config,
@@ -179,9 +183,9 @@ impl Udp {
         for i in 0..worker_count {
             let throttle =
                 create_throttle(config.throttle.as_ref(), config.bytes_per_second.as_ref())?
-                    .divide(
-                        NonZeroU32::new(worker_count.into()).expect("worker_count is always >= 1"),
-                    )?;
+                    .divide(NonZeroU32::new(worker_count.into()).unwrap_or_else(|| {
+                        unreachable!("worker_count is NonZeroU16, always >= 1")
+                    }))?;
 
             let mut worker_labels = labels.clone();
             if worker_count > 1 {
@@ -236,6 +240,10 @@ struct UdpWorker {
 }
 
 impl UdpWorker {
+    #[expect(
+        clippy::expect_used,
+        reason = "the wait_for_block branch is gated on `connection.is_some()` in the tokio::select! arm; the Option is guaranteed Some when this branch fires"
+    )]
     async fn spin(mut self) -> Result<(), Error> {
         debug!("UDP generator worker running");
         let mut connection = Option::<UdpSocket>::None;

lading/src/lib.rs

@@ -8,9 +8,6 @@
 #![deny(clippy::cargo)]
 #![expect(clippy::cast_precision_loss)]
 #![expect(clippy::multiple_crate_versions)]
-// Quarantine: workspace denies `clippy::expect_used`, but this crate still has
-// production `.expect()` sites awaiting cleanup. Remove once cleaned up.
-#![allow(clippy::expect_used)]
 
 use http_body_util::BodyExt;