Bytes* fixed (allows to build from bytearrays) per #827

construct/core.py

@@ -801,6 +801,8 @@ class Bytes(Construct):
 
     Parses into a bytes (of given length). Builds into the stream directly (but checks that given object matches specified length). Can also build from an integer for convenience (although BytesInteger should be used instead). Size is the specified length.
 
+    Can also build from a bytearray.
+
     :param length: integer or context lambda
 
     :raises StreamError: requested reading negative amount, could not read enough bytes, requested writing different amount than actual data, or could not write all bytes
@@ -841,6 +843,7 @@ def _parse(self, stream, context, path):
     def _build(self, obj, stream, context, path):
         length = self.length(context) if callable(self.length) else self.length
         data = integer2bytes(obj, length) if isinstance(obj, int) else obj
+        data = bytes(data) if type(data) is bytearray else data
         stream_write(stream, data, length, path)
         return data
 
@@ -864,6 +867,8 @@ class GreedyBytes(Construct):
 
     Parses the stream to the end. Builds into the stream directly (without checks). Size is undefined.
 
+    Can also build from a bytearray.
+
     :raises StreamError: stream failed when reading until EOF
     :raises StringError: building from non-bytes value, perhaps unicode
 
@@ -879,7 +884,8 @@ def _parse(self, stream, context, path):
         return stream_read_entire(stream, path)
 
     def _build(self, obj, stream, context, path):
-        stream_write(stream, obj, len(obj), path)
+        data = bytes(obj) if type(obj) is bytearray else obj
+        stream_write(stream, data, len(data), path)
         return obj
 
     def _emitparse(self, code):

docs/transition210.rst

@@ -6,6 +6,8 @@ Transition to 2.10
 Overall
 ==========
 
+Bytes GreedyBytes can build from bytearrays (not just bytes)
+
 Embedded and EmbeddedSwitch were permanently removed
 
 Exceptions always display path information

tests/test_core.py

@@ -25,6 +25,12 @@ def test_bytes():
 def test_greedybytes():
     common(GreedyBytes, b"1234", b"1234", SizeofError)
 
+def test_bytes_issue_827():
+    d = Bytes(3)
+    assert d.build(bytearray(b'\x01\x02\x03')) == b'\x01\x02\x03'
+    d = GreedyBytes
+    assert d.build(bytearray(b'\x01\x02\x03')) == b'\x01\x02\x03'
+
 def test_bitwise():
     common(Bitwise(Bytes(8)), b"\xff", b"\x01\x01\x01\x01\x01\x01\x01\x01", 1)
     common(Bitwise(Array(8,Bit)), b"\xff", [1,1,1,1,1,1,1,1], 1)