Add macos-system-configuration feature flag

Cargo.toml

@@ -27,7 +27,7 @@ features = [
 ]
 
 [features]
-default = ["default-tls", "http2"]
+default = ["default-tls", "http2", "macos-system-configuration"]
 
 # Note: this doesn't enable the 'native-tls' feature, which adds specific
 # functionality for it.
@@ -67,6 +67,9 @@ stream = ["tokio/fs", "dep:tokio-util", "dep:wasm-streams"]
 
 socks = ["dep:tokio-socks"]
 
+# Use the system's proxy configuration.
+macos-system-configuration = ["dep:system-configuration"]
+
 # Experimental HTTP/3 client.
 # Disabled while waiting for quinn to upgrade.
 #http3 = ["rustls-tls-manual-roots", "dep:h3", "dep:h3-quinn", "dep:quinn", "dep:futures-channel"]
@@ -170,7 +173,7 @@ futures-util = { version = "0.3.0", default-features = false, features = ["std",
 winreg = "0.50.0"
 
 [target.'cfg(target_os = "macos")'.dependencies]
-system-configuration = "0.5.1"
+system-configuration = { version = "0.5.1", optional = true }
 
 # wasm
 

src/proxy.rs

@@ -13,7 +13,7 @@ use std::collections::HashMap;
 use std::env;
 use std::error::Error;
 use std::net::IpAddr;
-#[cfg(target_os = "macos")]
+#[cfg(all(target_os = "macos", feature = "macos-system-configuration"))]
 use system_configuration::{
     core_foundation::{
         base::CFType,
@@ -947,7 +947,7 @@ fn get_from_platform_impl() -> Result<Option<String>, Box<dyn Error>> {
     Ok((proxy_enable == 1).then_some(proxy_server))
 }
 
-#[cfg(target_os = "macos")]
+#[cfg(all(target_os = "macos", feature = "macos-system-configuration"))]
 fn parse_setting_from_dynamic_store(
     proxies_map: &CFDictionary<CFString, CFType>,
     enabled_key: CFStringRef,
@@ -985,7 +985,7 @@ fn parse_setting_from_dynamic_store(
     None
 }
 
-#[cfg(target_os = "macos")]
+#[cfg(all(target_os = "macos", feature = "macos-system-configuration"))]
 fn get_from_platform_impl() -> Result<Option<String>, Box<dyn Error>> {
     let store = SCDynamicStoreBuilder::new("reqwest").build();
 
@@ -1016,12 +1016,18 @@ fn get_from_platform_impl() -> Result<Option<String>, Box<dyn Error>> {
     }
 }
 
-#[cfg(any(target_os = "windows", target_os = "macos"))]
+#[cfg(any(
+    target_os = "windows",
+    all(target_os = "macos", feature = "macos-system-configuration")
+))]
 fn get_from_platform() -> Option<String> {
     get_from_platform_impl().ok().flatten()
 }
 
-#[cfg(not(any(target_os = "windows", target_os = "macos")))]
+#[cfg(not(any(
+    target_os = "windows",
+    all(target_os = "macos", feature = "macos-system-configuration")
+)))]
 fn get_from_platform() -> Option<String> {
     None
 }