Fix no-default-features = true for non-nightly rust channels

.travis.yml

@@ -8,8 +8,8 @@ matrix:
       env: JOB=fuzz
       script: cargo build --features fuzz
     - rust: nightly
-      env: JOB=nostd
-      script: cargo build --no-default-features
+      env: JOB=test-nostd
+      script: cargo test --no-default-features --features alloc
     - rust: stable
       env: JOB=doc
       script: cargo doc

CHANGELOG.md

@@ -28,14 +28,27 @@ Released YYYY/MM/DD
 
 --------------------------------------------------------------------------------
 
+# 0.2.11
+
+Released 2018/08/09
+
+## Fixed
+
+* Fixed builds using `no-default-features = true` to not accidentally enable
+  `no_std` mode, which requires nightly rust, and break builds on non-nightly
+  channels. Enabling the `no_std` mode now requires disabling the `std` feature
+  *and* enabling the `alloc` feature.
+
+--------------------------------------------------------------------------------
+
 # 0.2.10
 
 Released 2018/08/08
 
 ## Added
 
-* Added support for `nostd`! This currently requires nightly Rust's `alloc`
-  feature to get access to `BTreeMap`. Enable `nostd` support by building
+* Added support for `no_std`! This currently requires nightly Rust's `alloc`
+  feature to get access to `BTreeMap`. Enable `no_std` support by building
   without the on-by-default `std` feature. [#148][]
 
 ## Fixed

Cargo.toml

@@ -30,26 +30,28 @@ required-features = ["afl"]
 [build-dependencies]
 glob = "0.2.11"
 
+[dependencies]
+cfg-if = "0.1.4"
+
 [dependencies.afl]
 optional = true
 version = "0.4"
 
-[dependencies.clap]
-optional = true
-version = "2.27.1"
-
 [dev-dependencies]
+clap = "2.27.1"
 diff = "0.1.10"
 
 [features]
 # Default features.
-default = ["cppfilt", "std"]
+default = ["std"]
 
-# Build using the `std` library. Disabling this feature enables `nostd` support.
+# Build using the `std` library. Disabling this and enabling the `alloc` feature
+# enables `no_std` support.
 std = []
 
-# Build the `c++filt` clone executable.
-cppfilt = ["clap"]
+# Use collections from the `alloc` crate rather than from `std`. Combined with
+# disabling `std`, this enables `no_std` support.
+alloc = []
 
 # Enable copious amounts of logging. This is for internal use only, and is only
 # useful for hacking on `cpp_demangle` itself.
@@ -62,10 +64,12 @@ run_libiberty_tests = []
 # Enable fuzzing support. This is for internal use only.
 fuzz = ["afl"]
 
-# DEPRECATED. Don't use this, it does nothing.
+# DEPRECATED. Don't use these features, they do nothing.
 #
 # TODO: remove on next breaking version bump.
 nightly = []
+cppfilt = []
+
 
 [profile.release]
 debug = true

README.md

@@ -34,7 +34,7 @@ Add `cpp_demangle` to your crate's `Cargo.toml`:
 
 ```toml
 [dependencies]
-cpp_demangle = "0.2.9"
+cpp_demangle = "0.2.11"
 ```
 
 And then demangle some C++ symbols!
@@ -53,13 +53,36 @@ let demangled = sym.to_string();
 assert_eq!(demangled, "space::foo(int, bool, char)");
 ```
 
+### `no_std` Support
+
+`cpp_demangle` may be configured for working in `no_std` environments that still
+have allocation support via the `alloc` crate. This is nightly rust only, at the
+moment, since the `alloc` crate's collections aren't stabilized.
+
+Disable the "std" feature, and enable the "alloc" feature:
+
+```tom
+[dependencies]
+cpp_demangle = {
+  version = "0.2.11",
+  default-features = false,
+  features = ["alloc"]
+}
+```
+
 ## Documentation
 
 [Documentation on docs.rs](https://docs.rs/cpp_demangle)
 
 Example programs:
 
-* [A `c++filt` clone](./src/bin/cppfilt.rs)
+* [A `c++filt` clone.](./src/bin/cppfilt.rs)
+
+  Install it locally with this command:
+
+  ```
+  cargo install cpp_demangle --example cppfilt
+  ```
 
 ## Implementation Status
 

src/lib.rs

@@ -30,41 +30,38 @@
 #![deny(missing_docs)]
 #![deny(missing_debug_implementations)]
 #![deny(unsafe_code)]
+
 // Clippy stuff.
 #![allow(unknown_lints)]
 #![allow(inline_always)]
 
-#![no_std]
-#![cfg_attr(not(feature = "std"), feature(alloc))]
-
-#[cfg(feature = "std")]
-#[macro_use]
-extern crate std;
-
-#[cfg(not(feature = "std"))]
-#[macro_use]
-extern crate core as std;
+#![cfg_attr(all(not(feature = "std"), feature = "alloc"), no_std)]
+#![cfg_attr(all(not(feature = "std"), feature = "alloc"), feature(alloc))]
 
-#[cfg(not(feature = "std"))]
 #[macro_use]
-extern crate alloc;
-
-#[cfg(feature = "std")]
-mod imports {
-    pub use std::boxed;
-    pub use std::vec;
-    pub use std::string;
-    pub use std::borrow;
-    pub use std::collections::btree_map;
-}
-
-#[cfg(not(feature = "std"))]
-mod imports {
-    pub use alloc::boxed;
-    pub use alloc::vec;
-    pub use alloc::string;
-    pub use alloc::borrow;
-    pub use alloc::collections::btree_map;
+extern crate cfg_if;
+
+cfg_if! {
+    if #[cfg(feature = "std")] {
+        mod imports {
+            pub use std::boxed;
+            pub use std::vec;
+            pub use std::string;
+            pub use std::borrow;
+            pub use std::collections::btree_map;
+        }
+    } else if #[cfg(feature = "alloc")] {
+        extern crate core as std;
+        #[macro_use]
+        extern crate alloc;
+        mod imports {
+            pub use alloc::boxed;
+            pub use alloc::vec;
+            pub use alloc::string;
+            pub use alloc::borrow;
+            pub use alloc::collections::btree_map;
+        }
+    }
 }
 
 use imports::*;