add regression tests for GIL ordering bug (issue #370)

.github/workflows/ci.yml

@@ -23,7 +23,7 @@ jobs:
       fail-fast: false
       matrix:
         go-version: [1.25.x, 1.24.x, 1.22.x, 1.21.x]
-        platform: [ubuntu-latest, windows-latest]
+        platform: [ubuntu-latest, windows-latest, macos-13]
         #platform: [ubuntu-latest, macos-latest, windows-latest]
     runs-on: ${{ matrix.platform }}
     steps:
@@ -59,6 +59,13 @@ jobs:
         # install goimports
         go install golang.org/x/tools/cmd/goimports@latest
 
+    - name: Install macOS packages
+      if: matrix.platform == 'macos-13'
+      run: |
+        # install pybindgen
+        python3 -m pip install --user -U pybindgen
+        # install goimports
+        go install golang.org/x/tools/cmd/goimports@latest
 
     - name: Build-Linux
       if: matrix.platform == 'ubuntu-latest'
@@ -77,6 +84,15 @@ jobs:
       if: matrix.platform == 'windows-latest'
       run: |
         go test -v ./...
+
+    - name: Build-macOS
+      if: matrix.platform == 'macos-13'
+      run: |
+        make
+    - name: Test macOS
+      if: matrix.platform == 'macos-13'
+      run: |
+        make test
     - name: Upload-Coverage
       if: matrix.platform == 'ubuntu-latest'
       uses: codecov/codecov-action@v4

SUPPORT_MATRIX.md

@@ -11,6 +11,7 @@ _examples/consts | yes
 _examples/cstrings | yes
 _examples/empty | yes
 _examples/funcs | yes
+_examples/gilstring | yes
 _examples/gobytes | yes
 _examples/gopygc | yes
 _examples/gostrings | yes

_examples/cgo/cgo.go

@@ -9,7 +9,7 @@ package cgo
 //#include <string.h>
 //#include <stdlib.h>
 //const char* cpkg_sprintf(const char *str) {
-//  char *o = (char*)malloc(strlen(str));
+//  char *o = (char*)malloc(strlen(str) + 1);
 //	sprintf(o, "%s", str);
 //	return o;
 //}

_examples/cgo/test.py

@@ -11,4 +11,12 @@
 print("cgo.Hi()= %s" % repr(cgo.Hi()).lstrip('u'))
 print("cgo.Hello(you)= %s" % repr(cgo.Hello("you")).lstrip('u'))
 
+# Regression test for GIL ordering bug (issue #370 / PR #386):
+# go functions returning string (go2py=C.CString) previously called C.CString
+# without holding the GIL, causing crashes under repeated calls.
+for _ in range(5000):
+    assert cgo.Hi() == 'hi from go\n'
+    assert cgo.Hello("world") == 'hello world from go\n'
+print("stress OK")
+
 print("OK")

_examples/gilstring/gilstring.go

@@ -0,0 +1,38 @@
+// Copyright 2026 The go-python Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package gilstring is a regression test for the GIL ordering bug (issue #370).
+// It exercises go2py string conversion through functions, struct fields,
+// slice elements, and map values — all of which previously ran C.CString
+// without holding the GIL, causing crashes under repeated calls.
+package gilstring
+
+import "fmt"
+
+// Add returns the sum of its arguments, mirroring simple.Add from the issue
+// report reproduction script.
+func Add(i, j int) int { return i + j }
+
+// Hello returns a greeting string, mirroring hi.Hello from the issue report
+// reproduction script. Returning a non-trivial string stresses go2py
+// string conversion (C.CString) on every call.
+func Hello(s string) string { return fmt.Sprintf("Hello, %s!", s) }
+
+// Item is a struct with a string field to exercise struct member string getters.
+type Item struct {
+	Label string
+	Count int
+}
+
+// MakeItem returns an Item with the given label.
+func MakeItem(s string) Item { return Item{Label: s, Count: len(s)} }
+
+// GetLabel returns the Label field of an Item.
+func GetLabel(i Item) string { return i.Label }
+
+// StringSlice returns a slice of strings.
+func StringSlice() []string { return []string{"alpha", "beta", "gamma"} }
+
+// StringMap returns a map with string values.
+func StringMap() map[string]string { return map[string]string{"key": "value"} }

_examples/gilstring/test.py

@@ -0,0 +1,37 @@
+# Copyright 2026 The go-python Authors.  All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+## py2/py3 compat
+from __future__ import print_function
+
+import gilstring
+
+# Regression test for GIL ordering bug (issue #370 / PR #386).
+# Mirrors the exact reproduction script from the issue report:
+#   for _ in range(5000):
+#       Add(2, 2)
+#       Hello('hi')
+# Integer arithmetic (Add) interleaved with string-returning calls (Hello)
+# stresses the go2py C.CString path that previously ran without the GIL held.
+N = 5000
+
+for _ in range(N):
+    assert gilstring.Add(2, 2) == 4
+    assert gilstring.Hello("hi") == "Hello, hi!"
+
+# Struct string fields, slice elements, and map values exercise additional
+# go2py string conversion paths from the same bug.
+for _ in range(N):
+    item = gilstring.MakeItem("hello")
+    assert item.Label == "hello", item.Label
+
+for _ in range(N):
+    s = gilstring.StringSlice()
+    assert s[0] == "alpha", s[0]
+
+for _ in range(N):
+    m = gilstring.StringMap()
+    assert m["key"] == "value", m["key"]
+
+print("OK")

main_test.go

@@ -49,6 +49,7 @@ var (
 		"_examples/cstrings":    []string{"py3"},
 		"_examples/pkgconflict": []string{"py3"},
 		"_examples/variadic":    []string{"py3"},
+		"_examples/gilstring":   []string{"py3"},
 	}
 
 	testEnvironment = os.Environ()
@@ -316,7 +317,6 @@ OK
 }
 
 func TestBindSimple(t *testing.T) {
-	t.Skip("Skipping due to Go 1.21+ CGO issue (see https://github.com/go-python/gopy/issues/370)")
 	// t.Parallel()
 	path := "_examples/simple"
 	testPkg(t, pkg{
@@ -546,7 +546,6 @@ OK
 }
 
 func TestBindCgoPackage(t *testing.T) {
-	t.Skip("Skipping due to Go 1.21+ CGO issue (see https://github.com/go-python/gopy/issues/370)")
 	// t.Parallel()
 	path := "_examples/cgo"
 	testPkg(t, pkg{
@@ -557,6 +556,7 @@ func TestBindCgoPackage(t *testing.T) {
 		want: []byte(`cgo.doc: '\nPackage cgo tests bindings of CGo-based packages.\n\n'
 cgo.Hi()= 'hi from go\n'
 cgo.Hello(you)= 'hello you from go\n'
+stress OK
 OK
 `),
 	})
@@ -785,6 +785,18 @@ OK
 	})
 }
 
+func TestGilString(t *testing.T) {
+	// t.Parallel()
+	path := "_examples/gilstring"
+	testPkg(t, pkg{
+		path:   path,
+		lang:   features[path],
+		cmd:    "build",
+		extras: nil,
+		want:   []byte("OK\n"),
+	})
+}
+
 func TestPackagePrefix(t *testing.T) {
 	// t.Parallel()
 	path := "_examples/package/mypkg"