Compile serde_derive separately from serde

url/Cargo.toml

@@ -17,22 +17,24 @@ edition = "2018"
 rust-version = "1.56"
 
 [dev-dependencies]
-serde = { version = "1.0", features = ["derive"] }
+serde_crate = { package = "serde", version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 bencher = "0.1"
 
 [dependencies]
 form_urlencoded = { version = "1.2.0", path = "../form_urlencoded" }
 idna = { version = "0.4.0", path = "../idna" }
 percent-encoding = { version = "2.3.0", path = "../percent_encoding" }
-serde = { version = "1.0", optional = true, features = ["derive"] }
+serde_crate = { package = "serde", version = "1.0.186", optional = true }
+serde_derive = { version = "1.0", optional = true }
 
 [features]
 default = []
 # Enable to use the #[debugger_visualizer] attribute. This feature requires Rust >= 1.71.
 debugger_visualizer = []
 # Expose internal offsets of the URL.
 expose_internals = []
+serde = ["serde_crate", "serde_derive"]
 
 [[test]]
 name = "url_wpt"

url/src/host.rs

@@ -12,11 +12,15 @@ use std::net::{Ipv4Addr, Ipv6Addr};
 
 use percent_encoding::{percent_decode, utf8_percent_encode, CONTROLS};
 #[cfg(feature = "serde")]
-use serde::{Deserialize, Serialize};
+use serde_derive::{Deserialize, Serialize};
 
 use crate::parser::{ParseError, ParseResult};
 
-#[cfg_attr(feature = "serde", derive(Deserialize, Serialize))]
+#[cfg_attr(
+    feature = "serde",
+    derive(Deserialize, Serialize),
+    serde(crate = "serde"),
+)]
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
 pub(crate) enum HostInternal {
     None,
@@ -37,7 +41,11 @@ impl From<Host<String>> for HostInternal {
 }
 
 /// The host name of an URL.
-#[cfg_attr(feature = "serde", derive(Deserialize, Serialize))]
+#[cfg_attr(
+    feature = "serde",
+    derive(Deserialize, Serialize),
+    serde(crate = "serde"),
+)]
 #[derive(Clone, Debug, Eq, Ord, PartialOrd, Hash)]
 pub enum Host<S = String> {
     /// A DNS domain name, as '.' dot-separated labels.

url/src/lib.rs

@@ -143,7 +143,7 @@ url = { version = "2", features = ["debugger_visualizer"] }
 pub use form_urlencoded;
 
 #[cfg(feature = "serde")]
-extern crate serde;
+extern crate serde_crate as serde;
 
 use crate::host::HostInternal;
 use crate::parser::{to_u32, Context, Parser, SchemeType, PATH_SEGMENT, USERINFO};

url/tests/wpt.rs

@@ -8,6 +8,8 @@
 
 //! Data-driven tests imported from web-platform-tests
 
+extern crate serde_crate as serde;
+
 use std::collections::HashMap;
 use std::fmt::Write;
 use std::panic;
@@ -16,6 +18,7 @@ use serde_json::Value;
 use url::Url;
 
 #[derive(Debug, serde::Deserialize)]
+#[serde(crate = "serde")]
 struct UrlTest {
     input: String,
     base: Option<String>,
@@ -24,14 +27,15 @@ struct UrlTest {
 }
 
 #[derive(Debug, serde::Deserialize)]
-#[serde(untagged)]
+#[serde(crate = "serde", untagged)]
 #[allow(clippy::large_enum_variant)]
 enum UrlTestResult {
     Ok(UrlTestOk),
     Fail(UrlTestFail),
 }
 
 #[derive(Debug, serde::Deserialize)]
+#[serde(crate = "serde")]
 struct UrlTestOk {
     href: String,
     protocol: String,
@@ -46,18 +50,21 @@ struct UrlTestOk {
 }
 
 #[derive(Debug, serde::Deserialize)]
+#[serde(crate = "serde")]
 struct UrlTestFail {
     failure: bool,
 }
 
 #[derive(Debug, serde::Deserialize)]
+#[serde(crate = "serde")]
 struct SetterTest {
     href: String,
     new_value: String,
     expected: SetterTestExpected,
 }
 
 #[derive(Debug, serde::Deserialize)]
+#[serde(crate = "serde")]
 struct SetterTestExpected {
     href: Option<String>,
     protocol: Option<String>,