Use f string instead of percent formatting

setup.py

@@ -35,13 +35,13 @@
 if mo:
     verstr = mo.group(1)
 else:
-    raise RuntimeError("Unable to find version string in %s." % (VERSIONFILE,))
+    raise RuntimeError(f"Unable to find version string in {VERSIONFILE}.")
 VSRE = r"^__wolfssl_version__ = ['\"]([^'\"]*)['\"]"
 mo = re.search(VSRE, verstrline, re.M)
 if mo:
     wolfverstr = mo.group(1)
 else:
-    raise RuntimeError("Unable to find version string in %s." % (VERSIONFILE,))
+    raise RuntimeError(f"Unable to find version string in {VERSIONFILE}.")
 
 
 # long_description

tests/test_delete_descriptor_binding.py

@@ -105,10 +105,10 @@ def test_lib_fn_class_attr_is_staticmethod(cls, attr):
     """
     raw = inspect.getattr_static(cls, attr)
     assert isinstance(raw, staticmethod), (
-        "%s.%s must be wrapped in staticmethod(...) to prevent Python's "
+        f"{cls.__name__}.{attr} must be wrapped in staticmethod(...) to prevent Python's "
         "descriptor protocol from injecting `self` as an extra positional "
         "argument when the underlying callable is a plain Python function "
-        "(e.g. a test mock). Got %r." % (cls.__name__, attr, type(raw))
+        f"(e.g. a test mock). Got {type(raw)!r}."
     )
 
 
@@ -179,7 +179,7 @@ def recorder(*args, **kwargs):
         assert kwargs == {}
         assert args == (native,), (
             "Random.__del__ must call _delete with only native_object, "
-            "but got args=%r" % (args,)
+            f"but got {args=!r}"
         )
     finally:
         Random._delete = original

wolfcrypt/asn.py

@@ -55,7 +55,7 @@ def der_to_pem(der, pem_type):
         if pem_length <= 0:
             raise WolfCryptApiError("Error getting required PEM buffer length.", pem_length)
 
-        pem = _ffi.new("byte[%d]" % pem_length)
+        pem = _ffi.new(f"byte[{pem_length}]")
         pem_length = _lib.wc_DerToPemEx(der, len(der), pem, pem_length,
                                         _ffi.NULL, pem_type)
         if pem_length <= 0:
@@ -80,7 +80,7 @@ def make_signature(data, hash_cls, key=None):
         hash_obj.update(data)
         digest = hash_obj.digest()
 
-        plaintext_sig = _ffi.new("byte[%d]" % _lib.MAX_DER_DIGEST_SZ)
+        plaintext_sig = _ffi.new(f"byte[{_lib.MAX_DER_DIGEST_SZ}]")
         hash_oid = hash_oid_from_class(hash_cls)
         plaintext_len = _lib.wc_EncodeSignature(plaintext_sig, digest,
                                                 len(digest), hash_oid)

wolfcrypt/hashes.py

@@ -105,7 +105,7 @@ def digest(self):
         way by this function; you can continue updating the object
         after calling this function.
         """
-        result = _ffi.new("byte[%d]" % self.digest_size)
+        result = _ffi.new(f"byte[{self.digest_size}]")
 
         if self._native_object:
             obj = _ffi.new(self._native_type)

wolfcrypt/hkdf.py

@@ -56,7 +56,7 @@ def HKDF(hash_cls, in_key, salt=None, info=None, out_len=None):
         if out_len is None:
             out_len = hash_cls.digest_size
 
-        out = _ffi.new("byte[%d]" % out_len)
+        out = _ffi.new(f"byte[{out_len}]")
         ret = _lib.wc_HKDF(
             hash_cls._type,
             in_key,
@@ -92,7 +92,7 @@ def HKDF_Extract(hash_cls, salt, in_key):
         in_key = t2b(in_key)
 
         out_len = hash_cls.digest_size
-        out = _ffi.new("byte[%d]" % out_len)
+        out = _ffi.new(f"byte[{out_len}]")
 
         ret = _lib.wc_HKDF_Extract(hash_cls._type, salt, len(salt), in_key, len(in_key), out)
         if ret != 0:
@@ -122,7 +122,7 @@ def HKDF_Expand(hash_cls, prk, info, out_len):
         if out_len is None or out_len <= 0:
             raise ValueError("out_len must be a positive integer")
 
-        out = _ffi.new("byte[%d]" % out_len)
+        out = _ffi.new(f"byte[{out_len}]")
 
         ret = _lib.wc_HKDF_Expand(
             hash_cls._type, prk, len(prk), info, len(info), out, out_len

wolfcrypt/pwdbased.py

@@ -33,7 +33,7 @@ def PBKDF2(password, salt, iterations, key_length, hash_type):
         if isinstance(password, str):
             password = str.encode(password)
 
-        key = _ffi.new("byte[%d]" %key_length)
+        key = _ffi.new(f"byte[{key_length}]")
         ret = _lib.wc_PBKDF2(key, password, len(password), salt, len(salt),
                              iterations, key_length, hash_type)
 

wolfcrypt/random.py

@@ -69,7 +69,7 @@ def bytes(self, length: int) -> __builtins__.bytes:
         """
         Generate and return a random sequence of length bytes.
         """
-        result = _ffi.new("byte[%d]" % length)
+        result = _ffi.new(f"byte[{length}]")
 
         assert self.native_object is not None
         ret = _lib.wc_RNG_GenerateBlock(self.native_object, result, length)