From 36a0a54423d0fba58e5da58e57c1c2cc5df00e7d Mon Sep 17 00:00:00 2001
From: Ashok Menon <ashok@mystenlabs.com>
Date: Mon, 11 Nov 2024 15:12:41 +0000
Subject: [PATCH] refactor(instant): Make instant an optional dependency

The `instant` crate is used by `backoff` to support the `Instant` type
when compiling to WASM, but it is currently unmaintained. This PR makes
the dependency optional, so that clients that do not need this feature
can avoid taking the dependency.

The feature is enabled by default so this change should not be breaking,
but it allows downstream packages to disable default features if they
don't need to take the dependency.

A separate PR is required to change the dependency to something like
`web-time` that is currently maintained.

## Test plan

Ran tests with and without the feature enabled:

```
cargo nextest run
cargo nextest run --no-default-features
cargo nextest run --no-default-features --features wasm-bindgen
cargo nextest run --features wasm-bindgen
```
---
 Cargo.toml           | 7 ++++---
 src/clock.rs         | 2 +-
 src/error.rs         | 2 +-
 src/exponential.rs   | 2 +-
 src/instant.rs       | 4 ++++
 src/lib.rs           | 1 +
 tests/exponential.rs | 3 +--
 7 files changed, 13 insertions(+), 8 deletions(-)
 create mode 100644 src/instant.rs

diff --git a/Cargo.toml b/Cargo.toml
index 52635ab..bcd79b4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,7 +19,7 @@ travis-ci = { repository = "ihrwein/backoff" }
 [dependencies]
 async_std_1 = { package = "async-std", version = "1.9", optional = true }
 futures-core = { version = "0.3.8", default-features = false, optional = true }
-instant = "0.1"
+instant = { version = "0.1", optional = true }
 pin-project-lite = { version = "0.2.7", optional = true }
 rand = "0.8"
 getrandom = "0.2"
@@ -32,8 +32,9 @@ tokio_1 = { package = "tokio", version = "1.0", features = ["macros", "time", "r
 futures-executor = "0.3"
 
 [features]
-default = []
-wasm-bindgen = ["instant/wasm-bindgen", "getrandom/js"]
+default = ["instant"]
+instant = ["dep:instant"]
+wasm-bindgen = ["instant", "instant/wasm-bindgen", "getrandom/js"]
 futures = ["futures-core", "pin-project-lite"]
 tokio = ["futures", "tokio_1"]
 async-std = ["futures", "async_std_1"]
diff --git a/src/clock.rs b/src/clock.rs
index f3ad9a0..23acac0 100644
--- a/src/clock.rs
+++ b/src/clock.rs
@@ -1,4 +1,4 @@
-use instant::Instant;
+use crate::instant::Instant;
 
 /// Clock returns the current time.
 pub trait Clock {
diff --git a/src/error.rs b/src/error.rs
index 5c32310..756ebf6 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -1,7 +1,7 @@
 use std::error;
 use std::fmt;
 
-use instant::Duration;
+use std::time::Duration;
 
 /// Error is the error value in an operation's
 /// result.
diff --git a/src/exponential.rs b/src/exponential.rs
index abaa28d..1c6b813 100644
--- a/src/exponential.rs
+++ b/src/exponential.rs
@@ -1,10 +1,10 @@
-use instant::Instant;
 use std::marker::PhantomData;
 use std::time::Duration;
 
 use crate::backoff::Backoff;
 use crate::clock::Clock;
 use crate::default;
+use crate::instant::Instant;
 
 #[derive(Debug)]
 pub struct ExponentialBackoff<C> {
diff --git a/src/instant.rs b/src/instant.rs
new file mode 100644
index 0000000..bdf8ff9
--- /dev/null
+++ b/src/instant.rs
@@ -0,0 +1,4 @@
+#[cfg(feature = "instant")]
+pub use instant::Instant;
+#[cfg(not(feature = "instant"))]
+pub use std::time::Instant;
diff --git a/src/lib.rs b/src/lib.rs
index 0196431..c89c2b0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -217,6 +217,7 @@ mod clock;
 pub mod default;
 mod error;
 pub mod exponential;
+pub mod instant;
 
 #[cfg(feature = "futures")]
 #[cfg_attr(docsrs, doc(cfg(feature = "futures")))]
diff --git a/tests/exponential.rs b/tests/exponential.rs
index 45bb9e9..57b138f 100644
--- a/tests/exponential.rs
+++ b/tests/exponential.rs
@@ -1,11 +1,10 @@
 extern crate backoff;
-extern crate instant;
 
 use backoff::backoff::Backoff;
 use backoff::exponential::ExponentialBackoff;
+use backoff::instant::Instant;
 use backoff::{Clock, SystemClock};
 
-use instant::Instant;
 use std::cell::RefCell;
 use std::time::Duration;