From ff2ed51ca2078af63d934ed7c42316c671779dae Mon Sep 17 00:00:00 2001
From: messense <messense@icloud.com>
Date: Mon, 11 Jul 2022 15:02:13 +0800
Subject: [PATCH] Use `cargo rustc --crate-type cdylib` on Rust nightly/dev

---
 Changelog.md   |  1 +
 src/compile.rs | 41 ++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/Changelog.md b/Changelog.md
index efe8c34b8..3273ce58e 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Add support for invoking with `python3 -m maturin` in [#1008](https://github.com/PyO3/maturin/pull/1008)
 * Fix detection of optional dependencies when declaring `features` in `pyproject.toml` in [#1014](https://github.com/PyO3/maturin/pull/1014)
 * Respect user specified Rust target in `maturin develop` in [#1016](https://github.com/PyO3/maturin/pull/1016)
+* Use `cargo rustc --crate-type cdylib` on Rust nightly/dev channel in [#1020](https://github.com/PyO3/maturin/pull/1020)
 
 ## [0.13.0] - 2022-07-09
 
diff --git a/src/compile.rs b/src/compile.rs
index df766fc7d..413267bda 100644
--- a/src/compile.rs
+++ b/src/compile.rs
@@ -14,6 +14,9 @@ use std::str;
 /// without `PYO3_NO_PYTHON` environment variable
 const PYO3_ABI3_NO_PYTHON_VERSION: (u64, u64, u64) = (0, 16, 4);
 
+/// crate types excluding `bin`, `cdylib` and `proc-macro`
+const LIB_CRATE_TYPES: [&str; 4] = ["lib", "dylib", "rlib", "staticlib"];
+
 /// Builds the rust crate into a native module (i.e. an .so or .dll) for a
 /// specific python version. Returns a mapping from crate type (e.g. cdylib)
 /// to artifact location.
@@ -23,7 +26,7 @@ pub fn compile(
     bindings_crate: &BridgeModel,
 ) -> Result<Vec<HashMap<String, PathBuf>>> {
     let root_pkg = context.cargo_metadata.root_package().unwrap();
-    let targets: Vec<_> = root_pkg
+    let mut targets: Vec<_> = root_pkg
         .targets
         .iter()
         .filter(|target| match bindings_crate {
@@ -31,6 +34,23 @@ pub fn compile(
             _ => target.kind.contains(&"cdylib".to_string()),
         })
         .collect();
+    if targets.is_empty() && !bindings_crate.is_bin() {
+        // No `crate-type = ["cdylib"]` in `Cargo.toml`
+        // Let's try compile one of the target with `--crate-type cdylib`
+        let lib_target = root_pkg
+            .targets
+            .iter()
+            .filter(|target| {
+                target
+                    .kind
+                    .iter()
+                    .any(|k| LIB_CRATE_TYPES.contains(&k.as_str()))
+            })
+            .next();
+        if let Some(target) = lib_target {
+            targets.push(target);
+        }
+    }
     if context.target.is_macos() && context.universal2 {
         compile_universal2(context, python_interpreter, bindings_crate, &targets)
     } else {
@@ -148,6 +168,25 @@ fn compile_target(
         cargo_rustc.release = true;
     }
 
+    // Add `--crate-type cdylib` if avaiable
+    if binding_target
+        .kind
+        .iter()
+        .any(|k| LIB_CRATE_TYPES.contains(&k.as_str()))
+    {
+        if let Ok(channel) = rustc_version::version_meta().map(|x| x.channel) {
+            if matches!(
+                channel,
+                rustc_version::Channel::Nightly | rustc_version::Channel::Dev
+            ) {
+                cargo_rustc
+                    .unstable_flags
+                    .push("unstable-options".to_string());
+                cargo_rustc.crate_type = vec!["cdylib".to_string()];
+            }
+        }
+    }
+
     let mut rust_flags = env::var_os("RUSTFLAGS");
 
     // We need to pass --bin / --lib