From b1a660e01124d72862779fd56a979db87a0d1f8f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alejandro=20Gonz=C3=A1lez?= <me@alegon.dev>
Date: Sat, 15 Apr 2023 15:22:20 +0200
Subject: [PATCH] Gate dependency on `crossbeam-channel` behind the `parallel`
 feature

`crossbeam-channel` is only used if the `parallel` flag is enabled, so
it can be gated behind that feature flag to potentially reduce the size
of the build dependency tree for dependent projects.

While at it, I've fixed several warnings emmitted in tests/flags.rs.
---
 Cargo.toml     | 7 +++++--
 tests/flags.rs | 6 +++++-
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 3b0ce3fd..86ee3a4b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -30,10 +30,13 @@ indexmap = "1.9.1"
 libdeflater = "0.11.0"
 log = "0.4.17"
 stderrlog = { version = "0.5.3", optional = true, default-features = false }
-crossbeam-channel = "0.5.6"
 bitvec = "1.0.1"
 rustc-hash = "1.1.0"
 
+[dependencies.crossbeam-channel]
+optional = true
+version = "0.5.6"
+
 [dependencies.filetime]
 optional = true
 version = "0.2.17"
@@ -61,7 +64,7 @@ rustc_version = "0.4.0"
 [features]
 binary = ["clap", "wild", "stderrlog"]
 default = ["binary", "filetime", "parallel", "zopfli"]
-parallel = ["rayon", "indexmap/rayon"]
+parallel = ["rayon", "indexmap/rayon", "crossbeam-channel"]
 freestanding = ["libdeflater/freestanding"]
 
 [lib]
diff --git a/tests/flags.rs b/tests/flags.rs
index 6ff0ee85..38db85b7 100644
--- a/tests/flags.rs
+++ b/tests/flags.rs
@@ -4,6 +4,7 @@ use oxipng::{InFile, OutFile};
 #[cfg(feature = "filetime")]
 use std::cell::RefCell;
 use std::fs::remove_file;
+#[cfg(feature = "zopfli")]
 use std::num::NonZeroU8;
 #[cfg(feature = "filetime")]
 use std::ops::Deref;
@@ -95,9 +96,12 @@ fn test_it_converts(
 
 #[test]
 fn verbose_mode() {
+    #[cfg(feature = "parallel")]
     use crossbeam_channel::{unbounded, Sender};
     use log::{set_logger, set_max_level, Level, LevelFilter, Log, Metadata, Record};
     use std::cell::RefCell;
+    #[cfg(not(feature = "parallel"))]
+    use std::sync::mpsc::{channel as unbounded, Sender};
 
     // Rust runs tests in parallel by default.
     // We want to make sure that we verify only logs from our test.
@@ -169,7 +173,7 @@ fn verbose_mode() {
         thread_exec();
     });
 
-    let mut logs: Vec<_> = receiver.into_iter().collect();
+    let logs: Vec<_> = receiver.into_iter().collect();
     println!("logs={:?}", logs);
     assert_eq!(logs.len(), 9);
     let expected_logs = [