From 0f72d1a3888c14314133f56ea3b3617885a82338 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Mon, 10 Apr 2017 17:01:11 -0700
Subject: [PATCH] Put rc impls behind a cfg

---
 serde/Cargo.toml       |  5 +++++
 serde/src/de/impls.rs  | 12 ++++++------
 serde/src/ser/impls.rs | 12 ++++++------
 travis.sh              | 10 +++++-----
 4 files changed, 22 insertions(+), 17 deletions(-)

diff --git a/serde/Cargo.toml b/serde/Cargo.toml
index 0c3f0c3b..12020eeb 100644
--- a/serde/Cargo.toml
+++ b/serde/Cargo.toml
@@ -64,6 +64,11 @@ alloc = ["unstable"]
 #    https://doc.rust-lang.org/collections/
 collections = ["alloc"]
 
+# Opt into impls for Rc<T> and Arc<T>. Serializing and deserializing these types
+# does not preserve identity and may result in multiple copies of the same data.
+# Be sure that this is what you want before enabling this feature.
+rc = []
+
 # Get serde_derive picked up by the Integer 32 playground. Not public API.
 #
 #    http://play.integer32.com/
diff --git a/serde/src/de/impls.rs b/serde/src/de/impls.rs
index ffe3291c..5416fab8 100644
--- a/serde/src/de/impls.rs
+++ b/serde/src/de/impls.rs
@@ -28,14 +28,14 @@ use std::ffi::{CString, OsString};
 #[cfg(all(feature = "std", feature = "unstable"))]
 use std::ffi::CStr;
 
-#[cfg(feature = "std")]
+#[cfg(all(feature = "rc", feature = "std"))]
 use std::rc::Rc;
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(all(feature = "rc", feature = "alloc", not(feature = "std")))]
 use alloc::rc::Rc;
 
-#[cfg(feature = "std")]
+#[cfg(all(feature = "rc", feature = "std"))]
 use std::sync::Arc;
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(all(feature = "rc", feature = "alloc", not(feature = "std")))]
 use alloc::arc::Arc;
 
 #[cfg(all(feature = "alloc", not(feature = "std")))]
@@ -1141,7 +1141,7 @@ impl<'de> Deserialize<'de> for Box<str> {
     }
 }
 
-#[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
 impl<'de, T: Deserialize<'de>> Deserialize<'de> for Arc<T> {
     fn deserialize<D>(deserializer: D) -> Result<Arc<T>, D::Error>
         where D: Deserializer<'de>
@@ -1151,7 +1151,7 @@ impl<'de, T: Deserialize<'de>> Deserialize<'de> for Arc<T> {
     }
 }
 
-#[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
 impl<'de, T: Deserialize<'de>> Deserialize<'de> for Rc<T> {
     fn deserialize<D>(deserializer: D) -> Result<Rc<T>, D::Error>
         where D: Deserializer<'de>
diff --git a/serde/src/ser/impls.rs b/serde/src/ser/impls.rs
index d0a74b97..e51a2999 100644
--- a/serde/src/ser/impls.rs
+++ b/serde/src/ser/impls.rs
@@ -17,16 +17,16 @@ use core::hash::{Hash, BuildHasher};
 use std::{net, ops, path};
 #[cfg(feature = "std")]
 use std::ffi::{CString, CStr, OsString, OsStr};
-#[cfg(feature = "std")]
+#[cfg(all(feature = "rc", feature = "std"))]
 use std::rc::Rc;
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(all(feature = "rc", feature = "alloc", not(feature = "std")))]
 use alloc::rc::Rc;
 #[cfg(feature = "std")]
 use std::time::Duration;
 
-#[cfg(feature = "std")]
+#[cfg(all(feature = "rc", feature = "std"))]
 use std::sync::Arc;
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(all(feature = "rc", feature = "alloc", not(feature = "std")))]
 use alloc::arc::Arc;
 
 #[cfg(all(feature = "alloc", not(feature = "std")))]
@@ -555,7 +555,7 @@ impl<T: ?Sized> Serialize for Box<T>
     }
 }
 
-#[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
 impl<T> Serialize for Rc<T>
     where T: Serialize
 {
@@ -567,7 +567,7 @@ impl<T> Serialize for Rc<T>
     }
 }
 
-#[cfg(any(feature = "std", feature = "alloc"))]
+#[cfg(all(feature = "rc", any(feature = "std", feature = "alloc")))]
 impl<T> Serialize for Arc<T>
     where T: Serialize
 {
diff --git a/travis.sh b/travis.sh
index a4023469..0f49838f 100755
--- a/travis.sh
+++ b/travis.sh
@@ -29,7 +29,7 @@ if [ -n "${CLIPPY}" ]; then
     fi
 
     cd "$DIR/serde"
-    cargo clippy --features unstable -- -Dclippy
+    cargo clippy --features 'rc unstable' -- -Dclippy
 
     cd "$DIR/serde_derive"
     cargo clippy --features unstable -- -Dclippy
@@ -47,7 +47,7 @@ else
     channel build --no-default-features
     channel build --no-default-features --features alloc
     channel build --no-default-features --features collections
-    channel test --features unstable
+    channel test --features 'rc unstable'
     cd "$DIR/test_suite/deps"
     channel build
     cd "$DIR/test_suite"
@@ -58,19 +58,19 @@ else
     CHANNEL=beta
     cargo clean
     cd "$DIR/serde"
-    channel build
+    channel build --features rc
     cd "$DIR/test_suite"
     channel test
 
     CHANNEL=stable
     cargo clean
     cd "$DIR/serde"
-    channel build
+    channel build --features rc
     channel build --no-default-features
 
     CHANNEL=1.13.0
     cargo clean
     cd "$DIR/serde"
-    channel build
+    channel build --features rc
     channel build --no-default-features
 fi