Bug 1785002 - Update tower-service to 0.3.2. r=emilio,supply-chain-reviewers

Differential Revision: https://phabricator.services.mozilla.com/D154756

Cargo.lock

@@ -5423,9 +5423,9 @@ checksum = "aa7c7f42dea4b1b99439786f5633aeb9c14c1b53f75e282803c2ec2ad545873c"
 
 [[package]]
 name = "tower-service"
-version = "0.3.1"
+version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "360dfd1d6d30e05fda32ace2c8c70e9c0a9da713275777f5a4dbb8a1893930c6"
+checksum = "b6bc1c9ce2b5135ac7f93c72918fc37feb872bdc6a5533a8b85eb4b86bfdae52"
 
 [[package]]
 name = "tracing"

supply-chain/audits.toml

@@ -655,6 +655,11 @@ criteria = "safe-to-deploy"
 version = "0.1.0"
 notes = "Simple algorithm crate with no unsafe code or capability usage."
 
+[[audits.tower-service]]
+who = "Mike Hommey <mh+mozilla@glandium.org>"
+criteria = "safe-to-run"
+delta = "0.3.1 -> 0.3.2"
+
 [[audits.tracy-rs]]
 who = "Glenn Watson <git@intuitionlibrary.com>"
 criteria = "safe-to-deploy"

third_party/rust/tower-service/.cargo-checksum.json

@@ -1 +1 @@
-{"files":{"CHANGELOG.md":"a202a1d257e8b3def187b371f26a47161afae5804040d7ad43d344809d1d1674","Cargo.toml":"09b0ebd19eac7f2185ac817da8d3877dea0725502d1ad1bbb96ea4fdf2621b42","LICENSE":"4249c8e6c5ebb85f97c77e6457c6fafc1066406eb8f1ef61e796fbdc5ff18482","README.md":"da9cb4815bf06e0991df6bf4e9f46272e26115dcc4e2c8f9ffc05e11d486179e","src/lib.rs":"d24ae2a7f7e075372839fddd13f833268d8e9ff8ffa3ca7aa1bf00e18fb57b80"},"package":"360dfd1d6d30e05fda32ace2c8c70e9c0a9da713275777f5a4dbb8a1893930c6"}
+{"files":{"CHANGELOG.md":"961cd98312a75f437e0dcd51eeb3bb61f0bbe778d5fb9203ab8a287bd9cfc84b","Cargo.toml":"81b3940c5bd437f362f4c52d442e49750263eae37b3188202c475340b7255f36","LICENSE":"4249c8e6c5ebb85f97c77e6457c6fafc1066406eb8f1ef61e796fbdc5ff18482","README.md":"da9cb4815bf06e0991df6bf4e9f46272e26115dcc4e2c8f9ffc05e11d486179e","src/lib.rs":"0acd9a6540ea50c0c60c212ba7ef89a7dd7542e99cc6854db2fdd1d5db63a715"},"package":"b6bc1c9ce2b5135ac7f93c72918fc37feb872bdc6a5533a8b85eb4b86bfdae52"}

third_party/rust/tower-service/CHANGELOG.md

@@ -1,5 +1,21 @@
 # Unreleased
 
+- None
+
+# 0.3.2 (June 17, 2022)
+
+## Added
+
+- **docs**: Clarify subtlety around cloning and readiness in the `Service` docs
+  ([#548])
+- **docs**: Clarify details around shared resource consumption in `poll_ready()`
+  ([#662])
+
+
+[#548]: https://github.com/tower-rs/tower/pull/548
+[#662]: https://github.com/tower-rs/tower/pull/662
+
+
 # 0.3.1 (November 29, 2019)
 
 - Improve example in `Service` docs. ([#510])

third_party/rust/tower-service/Cargo.toml

@@ -3,27 +3,32 @@
 # When uploading crates to the registry Cargo will automatically
 # "normalize" Cargo.toml files for maximal compatibility
 # with all versions of Cargo and also rewrite `path` dependencies
-# to registry (e.g., crates.io) dependencies
+# to registry (e.g., crates.io) dependencies.
 #
-# If you believe there's an error in this file please file an
+# If you are reading this file be aware that the original Cargo.toml
-# issue against the rust-lang/cargo repository. If you're
+# will likely look very different (and much more reasonable).
-# editing this file be aware that the upstream Cargo.toml
+# See Cargo.toml.orig for the original contents.
-# will likely look very different (and much more reasonable)
 
 [package]
 edition = "2018"
 name = "tower-service"
-version = "0.3.1"
+version = "0.3.2"
 authors = ["Tower Maintainers <team@tower-rs.com>"]
-description = "Trait representing an asynchronous, request / response based, client or server.\n"
+description = """
+Trait representing an asynchronous, request / response based, client or server.
+"""
 homepage = "https://github.com/tower-rs/tower"
-documentation = "https://docs.rs/tower-service/0.3.1"
+documentation = "https://docs.rs/tower-service/0.3.2"
 readme = "README.md"
-categories = ["asynchronous", "network-programming"]
+categories = [
+    "asynchronous",
+    "network-programming",
+]
 license = "MIT"
 repository = "https://github.com/tower-rs/tower"
 
 [dependencies]
+
 [dev-dependencies.futures]
 version = "0.3"
 
@@ -32,6 +37,10 @@ version = "0.2"
 
 [dev-dependencies.tokio]
 version = "1"
+features = [
+    "macros",
+    "time",
+]
 
 [dev-dependencies.tower-layer]
 version = "0.3"

third_party/rust/tower-service/src/lib.rs

@@ -1,11 +1,11 @@
-#![doc(html_root_url = "https://docs.rs/tower-service/0.3.1")]
 #![warn(
     missing_debug_implementations,
     missing_docs,
     rust_2018_idioms,
     unreachable_pub
 )]
-#![deny(broken_intra_doc_links)]
+#![forbid(unsafe_code)]
+// `rustdoc::broken_intra_doc_links` is checked on CI
 
 //! Definition of the core `Service` trait to Tower
 //!
@@ -231,6 +231,83 @@ use std::task::{Context, Poll};
 /// `Service` provides a mechanism by which the caller is able to coordinate
 /// readiness. `Service::poll_ready` returns `Ready` if the service expects that
 /// it is able to process a request.
+///
+/// # Be careful when cloning inner services
+///
+/// Services are permitted to panic if `call` is invoked without obtaining `Poll::Ready(Ok(()))`
+/// from `poll_ready`. You should therefore be careful when cloning services for example to move
+/// them into boxed futures. Even though the original service is ready, the clone might not be.
+///
+/// Therefore this kind of code is wrong and might panic:
+///
+/// ```rust
+/// # use std::pin::Pin;
+/// # use std::task::{Poll, Context};
+/// # use std::future::Future;
+/// # use tower_service::Service;
+/// #
+/// struct Wrapper<S> {
+///     inner: S,
+/// }
+///
+/// impl<R, S> Service<R> for Wrapper<S>
+/// where
+///     S: Service<R> + Clone + 'static,
+///     R: 'static,
+/// {
+///     type Response = S::Response;
+///     type Error = S::Error;
+///     type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>>>>;
+///
+///     fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+///         Poll::Ready(Ok(()))
+///     }
+///
+///     fn call(&mut self, req: R) -> Self::Future {
+///         let mut inner = self.inner.clone();
+///         Box::pin(async move {
+///             // `inner` might not be ready since its a clone
+///             inner.call(req).await
+///         })
+///     }
+/// }
+/// ```
+///
+/// You should instead use [`std::mem::replace`] to take the service that was ready:
+///
+/// ```rust
+/// # use std::pin::Pin;
+/// # use std::task::{Poll, Context};
+/// # use std::future::Future;
+/// # use tower_service::Service;
+/// #
+/// struct Wrapper<S> {
+///     inner: S,
+/// }
+///
+/// impl<R, S> Service<R> for Wrapper<S>
+/// where
+///     S: Service<R> + Clone + 'static,
+///     R: 'static,
+/// {
+///     type Response = S::Response;
+///     type Error = S::Error;
+///     type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>>>>;
+///
+///     fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+///         Poll::Ready(Ok(()))
+///     }
+///
+///     fn call(&mut self, req: R) -> Self::Future {
+///         let clone = self.inner.clone();
+///         // take the service that was ready
+///         let mut inner = std::mem::replace(&mut self.inner, clone);
+///         Box::pin(async move {
+///             inner.call(req).await
+///         })
+///     }
+/// }
+/// ```
 pub trait Service<Request> {
     /// Responses given by the service.
     type Response;
@@ -254,6 +331,12 @@ pub trait Service<Request> {
     /// Once `poll_ready` returns `Poll::Ready(Ok(()))`, a request may be dispatched to the
     /// service using `call`. Until a request is dispatched, repeated calls to
     /// `poll_ready` must return either `Poll::Ready(Ok(()))` or `Poll::Ready(Err(_))`.
+    ///
+    /// Note that `poll_ready` may reserve shared resources that are consumed in a subsequent
+    /// invocation of `call`. Thus, it is critical for implementations to not assume that `call`
+    /// will always be invoked and to ensure that such resources are released if the service is
+    /// dropped before `call` is invoked or the future returned by `call` is dropped before it
+    /// is polled.
     fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>>;
 
     /// Process the request and return the response asynchronously.