fix(secp256k1): support libsecp256k1 v0.7 seckey symbol rename

bitcointx/core/secp256k1.py

@@ -199,8 +199,19 @@ def _add_function_definitions(lib: ctypes.CDLL) -> Secp256k1_Capabilities:
     lib.secp256k1_ec_pubkey_tweak_add.restype = ctypes.c_int
     lib.secp256k1_ec_pubkey_tweak_add.argtypes = [ctypes.c_void_p, ctypes.c_char_p, ctypes.c_char_p]
 
-    lib.secp256k1_ec_privkey_tweak_add.restype = ctypes.c_int
-    lib.secp256k1_ec_privkey_tweak_add.argtypes = [ctypes.c_void_p, ctypes.c_char_p, ctypes.c_char_p]
+    # libsecp256k1 v0.7.0 renamed `secp256k1_ec_privkey_*` to
+    # `secp256k1_ec_seckey_*`. Expose the function under both names on the
+    # library handle so callers can use either spelling regardless of which
+    # symbol the underlying library exports.
+    # See: https://github.com/Simplexum/python-bitcointx/issues/88
+    if getattr(lib, 'secp256k1_ec_seckey_tweak_add', None):
+        _tweak_add = lib.secp256k1_ec_seckey_tweak_add
+    else:
+        _tweak_add = lib.secp256k1_ec_privkey_tweak_add
+    _tweak_add.restype = ctypes.c_int
+    _tweak_add.argtypes = [ctypes.c_void_p, ctypes.c_char_p, ctypes.c_char_p]
+    lib.secp256k1_ec_privkey_tweak_add = _tweak_add  # type: ignore[attr-defined]
+    lib.secp256k1_ec_seckey_tweak_add = _tweak_add  # type: ignore[attr-defined]
 
     lib.secp256k1_ec_pubkey_serialize.restype = ctypes.c_int
     lib.secp256k1_ec_pubkey_serialize.argtypes = [ctypes.c_void_p, ctypes.c_char_p, ctypes.POINTER(ctypes.c_size_t), ctypes.c_char_p, ctypes.c_uint]
@@ -210,10 +221,18 @@ def _add_function_definitions(lib: ctypes.CDLL) -> Secp256k1_Capabilities:
         lib.secp256k1_ec_pubkey_negate.restype = ctypes.c_int
         lib.secp256k1_ec_pubkey_negate.argtypes = [ctypes.c_void_p, ctypes.c_char_p]
 
-    if getattr(lib, 'secp256k1_ec_privkey_negate', None):
+    # libsecp256k1 v0.7.0 renamed `secp256k1_ec_privkey_negate` to
+    # `secp256k1_ec_seckey_negate`. Expose under both names for compatibility.
+    _negate = (
+        getattr(lib, 'secp256k1_ec_seckey_negate', None)
+        or getattr(lib, 'secp256k1_ec_privkey_negate', None)
+    )
+    if _negate is not None:
         has_privkey_negate = True
-        lib.secp256k1_ec_privkey_negate.restype = ctypes.c_int
-        lib.secp256k1_ec_privkey_negate.argtypes = [ctypes.c_void_p, ctypes.c_char_p]
+        _negate.restype = ctypes.c_int
+        _negate.argtypes = [ctypes.c_void_p, ctypes.c_char_p]
+        lib.secp256k1_ec_privkey_negate = _negate  # type: ignore[attr-defined]
+        lib.secp256k1_ec_seckey_negate = _negate  # type: ignore[attr-defined]
 
     lib.secp256k1_ec_pubkey_combine.restype = ctypes.c_int
     lib.secp256k1_ec_pubkey_combine.argtypes = [ctypes.c_void_p, ctypes.c_char_p, ctypes.POINTER(ctypes.c_char_p), ctypes.c_int]

bitcointx/tests/test_secp256k1_compat.py

@@ -0,0 +1,124 @@
+# Copyright (C) 2026 The python-bitcointx developers
+#
+# This file is part of python-bitcointx.
+#
+# It is subject to the license terms in the LICENSE file found in the top-level
+# directory of this distribution.
+
+"""Unit tests for the libsecp256k1 v0.7 compatibility shim.
+
+These tests use a fake ``ctypes.CDLL``-like object so that we can verify the
+function-binding logic in :func:`_add_function_definitions` independently of
+which libsecp256k1 happens to be installed on the test runner. See
+https://github.com/Simplexum/python-bitcointx/issues/88.
+"""
+
+import ctypes
+import unittest
+from typing import Any
+
+from bitcointx.core.secp256k1 import _add_function_definitions
+
+
+class _FakeFunc:
+    """Minimal stand-in for a ctypes-bound C function."""
+
+    def __init__(self, name: str) -> None:
+        self.name = name
+        self.restype: Any = None
+        self.argtypes: Any = None
+
+
+class _FakeLib:
+    """Fake CDLL exporting only the symbols listed in ``exports``.
+
+    Attribute access to any other name returns ``None`` from :func:`getattr`
+    (mirroring how ``getattr(lib, 'unknown', None)`` behaves in the real code),
+    and a direct attribute access raises :class:`AttributeError`.
+    """
+
+    def __init__(self, exports: set[str]) -> None:
+        self._exports = exports
+        for name in exports:
+            object.__setattr__(self, name, _FakeFunc(name))
+
+    def __getattr__(self, name: str) -> Any:
+        raise AttributeError(name)
+
+
+# Minimum set of unconditional symbols that ``_add_function_definitions``
+# always assigns argtypes/restype to, regardless of libsecp256k1 version.
+_CORE_SYMBOLS = {
+    "secp256k1_context_create",
+    "secp256k1_context_randomize",
+    "secp256k1_context_set_illegal_callback",
+    "secp256k1_ecdsa_sign",
+    "secp256k1_ecdsa_signature_serialize_der",
+    "secp256k1_ec_pubkey_create",
+    "secp256k1_ec_seckey_verify",
+    "secp256k1_ecdsa_signature_parse_der",
+    "secp256k1_ecdsa_signature_parse_compact",
+    "secp256k1_ecdsa_signature_normalize",
+    "secp256k1_ecdsa_verify",
+    "secp256k1_ec_pubkey_parse",
+    "secp256k1_ec_pubkey_tweak_add",
+    "secp256k1_ec_pubkey_serialize",
+    "secp256k1_ec_pubkey_combine",
+}
+
+
+class Test_Secp256k1_v07_Compat(unittest.TestCase):
+    def test_legacy_privkey_symbol(self) -> None:
+        """Pre-v0.7 libsecp256k1 only exports `secp256k1_ec_privkey_tweak_add`."""
+        lib = _FakeLib(_CORE_SYMBOLS | {"secp256k1_ec_privkey_tweak_add"})
+
+        _add_function_definitions(lib)  # type: ignore[arg-type]
+
+        # Both spellings must resolve to the same underlying function and be
+        # fully typed.
+        self.assertIs(lib.secp256k1_ec_privkey_tweak_add, lib.secp256k1_ec_seckey_tweak_add)
+        self.assertEqual(lib.secp256k1_ec_privkey_tweak_add.restype, ctypes.c_int)
+
+    def test_modern_seckey_symbol(self) -> None:
+        """v0.7+ libsecp256k1 only exports `secp256k1_ec_seckey_tweak_add`."""
+        lib = _FakeLib(_CORE_SYMBOLS | {"secp256k1_ec_seckey_tweak_add"})
+
+        _add_function_definitions(lib)  # type: ignore[arg-type]
+
+        self.assertIs(lib.secp256k1_ec_privkey_tweak_add, lib.secp256k1_ec_seckey_tweak_add)
+        self.assertEqual(lib.secp256k1_ec_seckey_tweak_add.restype, ctypes.c_int)
+
+    def test_both_symbols_present_prefers_modern(self) -> None:
+        """If both spellings are exported, the modern `seckey` name wins."""
+        lib = _FakeLib(
+            _CORE_SYMBOLS
+            | {
+                "secp256k1_ec_privkey_tweak_add",
+                "secp256k1_ec_seckey_tweak_add",
+            }
+        )
+        modern = lib.secp256k1_ec_seckey_tweak_add
+
+        _add_function_definitions(lib)  # type: ignore[arg-type]
+
+        self.assertIs(lib.secp256k1_ec_privkey_tweak_add, modern)
+        self.assertIs(lib.secp256k1_ec_seckey_tweak_add, modern)
+
+    def test_seckey_negate_alias(self) -> None:
+        """`secp256k1_ec_seckey_negate` (v0.7+) is aliased to the privkey name."""
+        lib = _FakeLib(
+            _CORE_SYMBOLS
+            | {
+                "secp256k1_ec_privkey_tweak_add",
+                "secp256k1_ec_seckey_negate",
+            }
+        )
+
+        cap = _add_function_definitions(lib)  # type: ignore[arg-type]
+
+        self.assertTrue(cap.has_privkey_negate)
+        self.assertIs(lib.secp256k1_ec_privkey_negate, lib.secp256k1_ec_seckey_negate)
+
+
+if __name__ == "__main__":
+    unittest.main()