pyo3-build-config: fix build for windows gnu targets

CHANGELOG.md

@@ -24,6 +24,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fix regression in 0.14.0 leading to incorrect code coverage being computed for `#[pyfunction]`s. [#1726](https://github.com/PyO3/pyo3/pull/1726)
 - Fix incorrect FFI definition of `Py_Buffer` on PyPy. [#1737](https://github.com/PyO3/pyo3/pull/1737)
 - Fix incorrect calculation of `dictoffset` on 32-bit Windows. [#1475](https://github.com/PyO3/pyo3/pull/1475)
+- Fix regression in 0.13.2 leading to linking to incorrect Python library on Windows "gnu" targets. [#1759](https://github.com/PyO3/pyo3/pull/1759)
 
 ## [0.14.1] - 2021-07-04
 

pyo3-build-config/src/impl_.rs

@@ -94,7 +94,7 @@ import os.path
 import platform
 import struct
 import sys
-from sysconfig import get_config_var
+from sysconfig import get_config_var, get_platform
 
 PYPY = platform.python_implementation() == "PyPy"
 
@@ -132,6 +132,7 @@ print_if_set("libdir", get_config_var("LIBDIR"))
 print_if_set("base_prefix", base_prefix)
 print("executable", sys.executable)
 print("calcsize_pointer", struct.calcsize("P"))
+print("mingw", get_platform() == "mingw")
 "#;
         let output = run_python_script(interpreter.as_ref(), SCRIPT)?;
         let map: HashMap<String, String> = parse_script_output(&output);
@@ -150,11 +151,7 @@ print("calcsize_pointer", struct.calcsize("P"))
         let implementation = map["implementation"].parse()?;
 
         let lib_name = if cfg!(windows) {
-            default_lib_name_windows(
+            default_lib_name_windows(version, abi3, map["mingw"].as_str() == "True")
-                version,
-                abi3,
-                &cargo_env_var("CARGO_CFG_TARGET_ENV").unwrap(),
-            )
         } else {
             default_lib_name_unix(
                 version,
@@ -899,7 +896,7 @@ fn windows_hardcoded_cross_compile(
         version,
         shared: true,
         abi3: is_abi3(),
-        lib_name: Some(default_lib_name_windows(version, false, "msvc")),
+        lib_name: Some(default_lib_name_windows(version, false, false)),
         lib_dir: cross_compile_config.lib_dir.to_str().map(String::from),
         executable: None,
         pointer_width: None,
@@ -936,10 +933,10 @@ fn load_cross_compile_config(
 // This contains only the limited ABI symbols.
 const WINDOWS_ABI3_LIB_NAME: &str = "python3";
 
-fn default_lib_name_windows(version: PythonVersion, abi3: bool, target_env: &str) -> String {
+fn default_lib_name_windows(version: PythonVersion, abi3: bool, mingw: bool) -> String {
     if abi3 {
         WINDOWS_ABI3_LIB_NAME.to_owned()
-    } else if target_env == "gnu" {
+    } else if mingw {
         // https://packages.msys2.org/base/mingw-w64-python
         format!("python{}.{}", version.major, version.minor)
     } else {
@@ -1278,19 +1275,19 @@ mod tests {
     #[test]
     fn default_lib_name_windows() {
         assert_eq!(
-            super::default_lib_name_windows(PythonVersion { major: 3, minor: 6 }, false, "mvsc"),
+            super::default_lib_name_windows(PythonVersion { major: 3, minor: 6 }, false, false),
             "python36",
         );
         assert_eq!(
-            super::default_lib_name_windows(PythonVersion { major: 3, minor: 6 }, true, "mvsc"),
+            super::default_lib_name_windows(PythonVersion { major: 3, minor: 6 }, true, false),
             "python3",
         );
         assert_eq!(
-            super::default_lib_name_windows(PythonVersion { major: 3, minor: 6 }, false, "gnu"),
+            super::default_lib_name_windows(PythonVersion { major: 3, minor: 6 }, false, true),
             "python3.6",
         );
         assert_eq!(
-            super::default_lib_name_windows(PythonVersion { major: 3, minor: 6 }, true, "gnu"),
+            super::default_lib_name_windows(PythonVersion { major: 3, minor: 6 }, true, true),
             "python3",
         );
     }