support python3-dll-a free-threaded generation (#4749)

newsfragments/4749.fixed.md

@@ -0,0 +1 @@
+Fix failure to link on Windows free-threaded Python when using the `generate-import-lib` feature.

newsfragments/4749.packaging.md

@@ -0,0 +1 @@
+Bump optional `python3-dll-a` dependency to 0.2.11.

pyo3-build-config/Cargo.toml

@@ -13,11 +13,11 @@ rust-version = "1.63"
 
 [dependencies]
 once_cell = "1"
-python3-dll-a = { version = "0.2.6", optional = true }
+python3-dll-a = { version = "0.2.11", optional = true }
 target-lexicon = "0.12.14"
 
 [build-dependencies]
-python3-dll-a = { version = "0.2.6", optional = true }
+python3-dll-a = { version = "0.2.11", optional = true }
 target-lexicon = "0.12.14"
 
 [features]

pyo3-build-config/src/impl_.rs

@@ -554,8 +554,17 @@ print("gil_disabled", get_config_var("Py_GIL_DISABLED"))
         if self.lib_dir.is_none() {
             let target = target_triple_from_env();
             let py_version = if self.abi3 { None } else { Some(self.version) };
-            self.lib_dir =
-                import_lib::generate_import_lib(&target, self.implementation, py_version)?;
+            let abiflags = if self.is_free_threaded() {
+                Some("t")
+            } else {
+                None
+            };
+            self.lib_dir = import_lib::generate_import_lib(
+                &target,
+                self.implementation,
+                py_version,
+                abiflags,
+            )?;
         }
         Ok(())
     }
@@ -1521,6 +1530,7 @@ fn default_cross_compile(cross_compile_config: &CrossCompileConfig) -> Result<In
                 .implementation
                 .unwrap_or(PythonImplementation::CPython),
             py_version,
+            None,
         )?;
     }
 
@@ -1889,6 +1899,7 @@ pub fn make_interpreter_config() -> Result<InterpreterConfig> {
             &host,
             interpreter_config.implementation,
             py_version,
+            None,
         )?;
     }
 

pyo3-build-config/src/import_lib.rs

@@ -19,6 +19,7 @@ pub(super) fn generate_import_lib(
     target: &Triple,
     py_impl: PythonImplementation,
     py_version: Option<PythonVersion>,
+    abiflags: Option<&str>,
 ) -> Result<Option<String>> {
     if target.operating_system != OperatingSystem::Windows {
         return Ok(None);
@@ -50,6 +51,7 @@ pub(super) fn generate_import_lib(
     ImportLibraryGenerator::new(&arch, &env)
         .version(py_version.map(|v| (v.major, v.minor)))
         .implementation(implementation)
+        .abiflags(abiflags)
         .generate(&out_lib_dir)
         .context("failed to generate python3.dll import library")?;