Debug Windows CI

.github/setup-rust-windows/action.yml

@@ -11,9 +11,9 @@ inputs:
 runs:
   using: composite
   steps:
-    - uses: dtolnay/rust-toolchain@ab40b01f54fe82bdf65693ea090a1e4942c136e7 # 1.91.1
+    - uses: dtolnay/rust-toolchain@f133eefe930d61f0d9371efd474daf0125ed3dd1 # 1.95.0
       with:
-        toolchain: 1.91.1
+        toolchain: 1.95.0
         targets: i686-pc-windows-msvc,x86_64-pc-windows-msvc,aarch64-pc-windows-msvc
     # LIBCLANG_PATH must be set explicitly so the vcxproj uses the LLVM we
     # install here rather than the VS-bundled LLVM whose clang headers have

.github/workflows/build.yml

@@ -353,9 +353,9 @@ jobs:
       - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           persist-credentials: false
-      - uses: dtolnay/rust-toolchain@ab40b01f54fe82bdf65693ea090a1e4942c136e7 # 1.91.1
+      - uses: dtolnay/rust-toolchain@f133eefe930d61f0d9371efd474daf0125ed3dd1 # 1.95.0
         with:
-          toolchain: 1.91.1
+          toolchain: 1.95.0
           targets: ${{ matrix.arch }}-linux-android
       - name: Build and test
         run: JAVA_HOME="${JAVA_HOME_21_X64:-$JAVA_HOME_21_arm64}" python3 Platforms/Android ci --fast-ci ${{ matrix.arch }}-linux-android
@@ -370,9 +370,9 @@ jobs:
       - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           persist-credentials: false
-      - uses: dtolnay/rust-toolchain@ab40b01f54fe82bdf65693ea090a1e4942c136e7 # 1.91.1
+      - uses: dtolnay/rust-toolchain@f133eefe930d61f0d9371efd474daf0125ed3dd1 # 1.95.0
         with:
-          toolchain: 1.91.1
+          toolchain: 1.95.0
           targets: aarch64-apple-ios-sim
       # GitHub recommends explicitly selecting the desired Xcode version:
       # https://github.com/actions/runner-images/issues/12541#issuecomment-3083850140

.github/workflows/reusable-wasi.yml

@@ -47,9 +47,9 @@ jobs:
       uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
       with:
         python-version: '3.x'
-    - uses: dtolnay/rust-toolchain@ab40b01f54fe82bdf65693ea090a1e4942c136e7 # 1.91.1
+    - uses: dtolnay/rust-toolchain@f133eefe930d61f0d9371efd474daf0125ed3dd1 # 1.95.0
       with:
-        toolchain: 1.91.1
+        toolchain: 1.95.0
         targets: wasm32-wasip1
     - name: "Runner image version"
       run: echo "IMAGE_OS_VERSION=${ImageOS}-${ImageVersion}" >> "$GITHUB_ENV"

.github/workflows/reusable-windows.yml

@@ -41,6 +41,7 @@ jobs:
       if: inputs.arch != 'Win32'
       run: echo "::add-matcher::.github/problem-matchers/msvc.json"
     - name: Build CPython
+      id: build_cpython
       # msvc::musttail is not supported for debug builds, so we have to
       # switch to release.
       run: >-
@@ -50,6 +51,20 @@ jobs:
         -p "${ARCH}"
         ${{ fromJSON(inputs.free-threading) && '--disable-gil' || '' }}
       shell: bash
+    - name: Upload Rust linker diagnostics
+      if: failure() && steps.build_cpython.outcome == 'failure'
+      uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
+      with:
+        name: windows-rust-link-diagnostics-${{ inputs.arch }}-${{ inputs.interpreter }}-${{ inputs.free-threading }}
+        if-no-files-found: warn
+        path: |
+          PCbuild/obj/**/_base64/cargo/**/build/cpython-sys-*/out/c_api.rs
+          PCbuild/obj/**/_base64/cargo/**/build/*/output
+          PCbuild/obj/**/_base64/cargo/**/.fingerprint/*/run-build-script-*.json
+          PCbuild/obj/**/_base64/cargo/**/deps/rustc*/
+          PCbuild/obj/**/pythoncore/pythoncore.tlog/link.*.tlog
+          PCbuild/**/python*.dll
+          PCbuild/**/python*.lib
     - name: Display build info
       run: .\\python.bat -m test.pythoninfo
     - name: Tests

Cargo.toml

@@ -4,3 +4,7 @@ members = [
     "Modules/_base64", "Modules/cpython-build-helper", "Modules/cpython-rust-staticlib",
     "Modules/cpython-sys"
 ]
+
+[workspace.package]
+# Make sure to also update the Rust toolchains in GitHub Actions whenever this version is modified
+rust-version = "1.95"

Modules/_base64/Cargo.toml

@@ -2,6 +2,7 @@
 name = "_base64"
 version = "0.1.0"
 edition = "2024"
+rust-version.workspace = true
 
 [dependencies]
 cpython-sys ={ path = "../cpython-sys" }

Modules/cpython-build-helper/Cargo.toml

@@ -2,6 +2,7 @@
 name = "cpython-build-helper"
 version = "0.1.0"
 edition = "2024"
+rust-version.workspace = true
 
 [dependencies]
 shlex = "1.3"

Modules/cpython-rust-staticlib/Cargo.toml

@@ -2,6 +2,7 @@
 name = "cpython-rust-staticlib"
 version = "0.1.0"
 edition = "2024"
+rust-version.workspace = true
 
 [dependencies]
 _base64 ={ path = "../_base64" }

Modules/cpython-sys/Cargo.toml

@@ -2,9 +2,12 @@
 name = "cpython-sys"
 version = "0.1.0"
 edition = "2024"
+rust-version.workspace = true
 
 [dependencies]
 
 [build-dependencies]
 bindgen = "0.72.1"
+prettyplease = "0.2.37"
 shlex = "1.3"
+syn = { version = "2.0.110", features = ["full", "parsing"] }

Modules/cpython-sys/build.rs

@@ -324,52 +324,24 @@ fn patch_windows_imported_pointer_globals(bindings: String, dll_name: &str) -> S
     // The fix: annotate pointer-valued extern statics with `raw-dylib` on
     // Windows so Rust generates the import thunk itself and handles the IAT
     // indirection correctly — two loads, matching `__declspec(dllimport)`.
-    let lines: Vec<_> = bindings.lines().collect();
-    let mut patched = String::with_capacity(bindings.len());
-    let mut index = 0;
-
-    while index < lines.len() {
-        if lines[index] == "unsafe extern \"C\" {"
-            && lines
-                .get(index + 1)
-                .and_then(|l| parse_pointer_static_decl(l))
-                .is_some()
-            && lines.get(index + 2).is_some_and(|l| l.trim() == "}")
-        {
-            patched.push_str(&format!(
-                "#[cfg_attr(windows, link(name = \"{dll_name}\", kind = \"raw-dylib\"))]\n"
-            ));
-            // Keep the original extern block unchanged.
-            for i in index..index + 3 {
-                patched.push_str(lines[i]);
-                patched.push('\n');
-            }
-            index += 3;
+    let mut file = syn::parse_file(&bindings).expect("bindgen emitted invalid Rust");
+
+    for item in &mut file.items {
+        let syn::Item::ForeignMod(foreign_mod) = item else {
+            continue;
+        };
+        let [syn::ForeignItem::Static(static_item)] = foreign_mod.items.as_slice() else {
+            continue;
+        };
+        if !matches!(*static_item.ty, syn::Type::Ptr(_)) {
             continue;
         }
-
-        patched.push_str(lines[index]);
-        patched.push('\n');
-        index += 1;
-    }
-
-    patched
-}
-
-fn parse_pointer_static_decl(line: &str) -> Option<(&str, bool, &str)> {
-    let mut decl = line.trim().strip_prefix("pub static ")?;
-    let is_mut = decl.starts_with("mut ");
-    if is_mut {
-        decl = decl.strip_prefix("mut ")?;
-    }
-
-    let (name, ty) = decl.split_once(':')?;
-    let ty = ty.trim().strip_suffix(';')?;
-    if !ty.starts_with('*') {
-        return None;
+        foreign_mod.attrs.push(syn::parse_quote!(
+            #[cfg_attr(windows, link(name = #dll_name, kind = "raw-dylib"))]
+        ));
     }
 
-    Some((name.trim(), is_mut, ty))
+    prettyplease::unparse(&file)
 }
 
 fn add_target_clang_args(