Fix clippy::missing-panics-doc

.bazelrc

@@ -46,7 +46,7 @@ build --aspects=@rules_rust//rust:defs.bzl%rust_clippy_aspect
 
 # TODO(aaronmondal): Extend these flags until we can run with clippy::pedantic.
 # TODO(aaronmondal): Fix dependency_on_unit_never_type_fallback.
-build --@rules_rust//:clippy_flags=-Dwarnings,-Adependency_on_unit_never_type_fallback,-Dclippy::uninlined_format_args,-Dclippy::manual_string_new
+build --@rules_rust//:clippy_flags=-Dwarnings,-Adependency_on_unit_never_type_fallback,-Dclippy::uninlined_format_args,-Dclippy::manual_string_new,-Dclippy::missing-panics-doc
 build --@rules_rust//:clippy.toml=//:clippy.toml
 
 test --@rules_rust//:rustfmt.toml=//:.rustfmt.toml

nativelink-metric/nativelink-metric-macro-derive/src/lib.rs

@@ -190,6 +190,9 @@ impl<'a> ToTokens for MetricStruct<'a> {
     }
 }
 
+/// # Panics
+///
+/// This function will panic if the `MetricsComponent` macro is applied to anything other than a struct.
 #[proc_macro_derive(MetricsComponent, attributes(metric))]
 pub fn metrics_component_derive(input: TokenStream) -> TokenStream {
     let input = parse_macro_input!(input as DeriveInput);

nativelink-scheduler/src/worker.rs

@@ -119,6 +119,13 @@ fn reduce_platform_properties(
 }
 
 impl Worker {
+    /// Creates a new `Worker` with the specified ID, platform properties, sender, and timestamp.
+    ///
+    /// # Panics
+    ///
+    /// This function will panic if the system time is earlier than the Unix epoch.
+    /// The panic occurs due to the call to `SystemTime::now().duration_since(UNIX_EPOCH).unwrap()`,
+    /// which will fail if the system clock is misconfigured or set to a time before the Unix epoch.
     pub fn new(
         id: WorkerId,
         platform_properties: PlatformProperties,

nativelink-service/src/worker_api_server.rs

@@ -50,6 +50,18 @@ pub struct WorkerApiServer {
 }
 
 impl WorkerApiServer {
+    /// Creates a new `WorkerApiServer` with the given configuration and schedulers.
+    ///
+    /// # Panics
+    ///
+    /// This function panics if the system time is earlier than the Unix epoch.
+    /// The panic occurs in two situations:
+    /// - When retrieving the system time for scheduler timeouts (`SystemTime::now().duration_since(UNIX_EPOCH)`).
+    /// - During server creation, if the system time is invalid, it will trigger an internal error.
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if the server could not be created with the given configuration and schedulers.
     pub fn new(
         config: &WorkerApiConfig,
         schedulers: &HashMap<String, Arc<dyn WorkerScheduler>>,

nativelink-store/src/s3_store.rs

@@ -260,6 +260,16 @@ where
     I: InstantWrapper,
     NowFn: Fn() -> I + Send + Sync + Unpin + 'static,
 {
+    /// Creates a new S3 store with the specified configuration and time function.
+    ///
+    /// # Panics
+    ///
+    /// This function will panic if the application name provided to the AWS SDK is invalid.
+    /// The panic occurs with the message `"valid app name"` in the call to `AppName::new()`.
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if there is an issue with creating the S3 client or other components.
     pub async fn new(
         config: &nativelink_config::stores::S3Store,
         now_fn: NowFn,

nativelink-store/src/shard_store.rs

@@ -45,6 +45,16 @@ pub struct ShardStore {
 }
 
 impl ShardStore {
+    /// Creates a new `ShardStore` with the given configuration and stores.
+    ///
+    /// # Panics
+    ///
+    /// This function will panic if the `weights` vector is empty when attempting to modify the last element
+    /// using `unwrap()`. This panic should not occur as long as the `config.stores` is not empty, as validated earlier.
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if the number of `config.stores` does not match the number of `stores`, or if `config.stores` is empty.
     pub fn new(
         config: &nativelink_config::stores::ShardStore,
         stores: Vec<Store>,

nativelink-util/src/buf_channel.rs

@@ -275,6 +275,14 @@ impl DropCloserReadHalf {
     ///
     /// On error the state of the stream is undefined and the caller should not
     /// attempt to use the stream again.
+    /// # Panics
+    ///
+    /// This function will panic if the `recent_data` is not empty after draining it.
+    /// Specifically, it panics with the message `"Recent_data should be empty"`.
+    ///
+    /// # Errors
+    ///
+    /// Returns an error if `bytes_received` exceeds `max_recent_data_size`.
     pub fn try_reset_stream(&mut self) -> Result<(), Error> {
         if self.bytes_received > self.max_recent_data_size {
             return Err(make_err!(
@@ -313,6 +321,11 @@ impl DropCloserReadHalf {
     }
 
     /// Peek the next set of bytes in the stream without consuming them.
+    ///
+    /// # Panics
+    ///
+    /// This function will panic if `queued_data` is empty after attempting to receive data.
+    /// The panic occurs with the message `"Should have data in the queue"`.
     pub async fn peek(&mut self) -> &Result<Bytes, Error> {
         if self.queued_data.is_empty() {
             let chunk = self.recv().await;

nativelink-util/src/evicting_map.rs

@@ -210,6 +210,11 @@ where
     /// and return the number of items that were processed.
     /// The `handler` function should return `true` to continue processing the next item
     /// or `false` to stop processing.
+    ///
+    /// # Panics
+    ///
+    /// This function will panic if the `btree` index is not properly initialized and is `None` after attempting to rebuild it.
+    /// The panic occurs due to calling `unwrap()` on a `None` value.
     pub async fn range<F, Q>(&self, prefix_range: impl RangeBounds<Q>, mut handler: F) -> u64
     where
         F: FnMut(&K, &T) -> bool,

nativelink-util/src/fastcdc.rs

@@ -51,6 +51,13 @@ pub struct FastCDC {
 }
 
 impl FastCDC {
+    /// Creates a new instance with the specified minimum, average, and maximum sizes.
+    ///
+    /// # Panics
+    ///
+    /// This function will panic if:
+    /// - `min_size` is not less than `avg_size`, in which case it panics with the message `"Expected {min_size} < {avg_size}"`.
+    /// - `avg_size` is not less than `max_size`, in which case it panics with the message `"Expected {avg_size} < {max_size}"`.
     pub fn new(min_size: usize, avg_size: usize, max_size: usize) -> Self {
         assert!(min_size < avg_size, "Expected {min_size} < {avg_size}");
         assert!(avg_size < max_size, "Expected {avg_size} < {max_size}");

nativelink-util/src/metrics_utils.rs

@@ -324,6 +324,13 @@ pub struct CounterWithTime {
 
 impl CounterWithTime {
     #[inline]
+    /// Increments the counter and updates the last time to the current system time.
+    ///
+    /// # Panics
+    ///
+    /// This function will panic if the system time is earlier than the Unix epoch.
+    /// This happens because `SystemTime::now().duration_since(UNIX_EPOCH).unwrap()` is called,
+    /// which panics if the system clock is incorrect or misconfigured.
     pub fn inc(&self) {
         if !metrics_enabled() {
             return;

nativelink-util/src/origin_context.rs

@@ -319,6 +319,12 @@ impl<T> ContextAwareFuture<T> {
     /// active context.
     #[must_use = "futures do nothing unless you `.await` or poll them"]
     #[inline]
+    /// Creates a new `ContextAwareFuture` from the active origin context.
+    ///
+    /// # Panics
+    ///
+    /// This function will panic if the `ActiveOriginContext` is not set (i.e., it returns `None`).
+    /// The panic occurs with the message `"OriginContext must be set"`.
     pub fn new_from_active(inner: Instrumented<T>) -> ContextAwareFuture<T> {
         match ActiveOriginContext::get() {
             Some(ctx) => ContextAwareFuture::new(Some(ctx), inner),

nativelink-worker/src/worker_utils.rs

@@ -26,6 +26,19 @@ use nativelink_proto::com::github::trace_machina::nativelink::remote_execution::
 use tokio::process;
 use tracing::{event, Level};
 
+/// Creates a `SupportedProperties` object based on the provided worker properties.
+///
+/// # Panics
+///
+/// This function will panic if the process fails and the exit status code cannot be retrieved
+/// (i.e., `process_output.status.code().unwrap()` returns `None`). This might happen if the process was terminated by a signal and no exit code was available.
+///
+/// # Errors
+///
+/// Returns an error if:
+/// - A worker property query command cannot be parsed.
+/// - A worker property query command fails to execute.
+/// - The process output cannot be converted to UTF-8.
 pub async fn make_supported_properties<S: BuildHasher>(
     worker_properties: &HashMap<String, WorkerProperty, S>,
 ) -> Result<SupportedProperties, Error> {