*/Cargo.toml: Update to 2021 edition (prometheus#65)

As suggested in prometheus#64,
this commit update edition key of manifest file into 2021.

As documented in 2021 edition guide(https://doc.rust-lang.org/edition-guide/rust-2021/IntoIterator-for-arrays.html),
array.into_iter() now returns owned value instead of references,
This commit changes previous doc comments to utilize new behavior.

Signed-off-by: Doehyun Baek <doehyunbaek@gmail.com>

CHANGELOG.md

@@ -4,6 +4,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.17.0] - unreleased
+
+### Changed
+
+- Updates to Rust 2021 Edition. See [PR 65].
+
+[PR 65]: https://github.com/prometheus/client_rust/pull/65
+
 ## [0.16.0]
 
 ### Changed

Cargo.toml

@@ -1,8 +1,8 @@
 [package]
 name = "prometheus-client"
-version = "0.16.0"
+version = "0.17.0"
 authors = ["Max Inden <mail@max-inden.de>"]
-edition = "2018"
+edition = "2021"
 description = "Open Metrics client library allowing users to natively instrument applications."
 license = "Apache-2.0 OR MIT"
 keywords = ["openmetrics", "prometheus", "metrics", "instrumentation", "monitoring"]
@@ -17,7 +17,7 @@ members = ["derive-text-encode"]
 dtoa = "1.0"
 itoa = "1.0"
 owning_ref = "0.4"
-prometheus-client-derive-text-encode = { version = "0.2.0", path = "derive-text-encode" }
+prometheus-client-derive-text-encode = { version = "0.3.0", path = "derive-text-encode" }
 
 [dev-dependencies]
 async-std = { version = "1", features = ["attributes"] }

derive-text-encode/Cargo.toml

@@ -1,8 +1,8 @@
 [package]
 name = "prometheus-client-derive-text-encode"
-version = "0.2.0"
+version = "0.3.0"
 authors = ["Max Inden <mail@max-inden.de>"]
-edition = "2018"
+edition = "2021"
 description = "Auxiliary crate to derive text Encode trait from prometheus-client."
 license = "Apache-2.0 OR MIT"
 repository = "https://github.com/prometheus/client_rust"

src/metrics/family.rs

@@ -144,9 +144,9 @@ pub trait MetricConstructor<M> {
 /// ```
 /// # use prometheus_client::metrics::family::{Family};
 /// # use prometheus_client::metrics::histogram::Histogram;
-/// let custom_buckets = vec![0.0, 10.0, 100.0];
+/// let custom_buckets = [0.0, 10.0, 100.0];
 /// let metric = Family::<(), Histogram, _>::new_with_constructor(|| {
-///     Histogram::new(custom_buckets.clone().into_iter())
+///     Histogram::new(custom_buckets.into_iter())
 /// });
 /// # metric.get_or_create(&());
 /// ```

src/metrics/histogram.rs

@@ -23,9 +23,10 @@ use std::sync::{Arc, Mutex, MutexGuard};
 /// ```
 /// # use prometheus_client::metrics::histogram::Histogram;
 /// // Default values from go client(https://github.com/prometheus/client_golang/blob/5d584e2717ef525673736d72cd1d12e304f243d7/prometheus/histogram.go#L68)
-/// let histogram = Histogram::new(IntoIterator::into_iter([
+/// let custom_buckets = [
 ///    0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, 10.0,
-/// ]));
+/// ];
+/// let histogram = Histogram::new(custom_buckets.into_iter());
 /// histogram.observe(4.2);
 /// ```
 // TODO: Consider using atomics. See