pyln.proto.message.*: add type annotations.

Other changes along the way:

1. In a couple of places we passed None as a dummy for for
   `otherfields` where {} is just as good.
2. Turned bytes into hex for errors.
3. Remove nonsensical (unused) get_tlv_by_number() function from MessageNamespace
4. Renamed unrelated-but-overlapping `field_from_csv` and
   `type_from_csv` static methods, since mypy thought they should have
   the same type.
5. Unknown tlv fields are placed in dict as strings, not ints, for
   type simplicity.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

.gitignore

@@ -11,6 +11,7 @@
 *.po
 *.pyc
 .cppcheck-suppress
+.mypy_cache
 TAGS
 tags
 ccan/tools/configurator/configurator

contrib/pyln-proto/pyln/proto/message/array_types.py

@@ -1,4 +1,8 @@
 from .fundamental_types import FieldType, IntegerType, split_field
+from typing import List, Optional, Dict, Tuple, TYPE_CHECKING, Any
+from io import BufferedIOBase
+if TYPE_CHECKING:
+    from .message import SubtypeType, TlvStreamType
 
 
 class ArrayType(FieldType):
@@ -8,11 +12,11 @@ These are not in the namespace, but generated when a message says it
 wants an array of some type.
 
     """
-    def __init__(self, outer, name, elemtype):
+    def __init__(self, outer: 'SubtypeType', name: str, elemtype: FieldType):
         super().__init__("{}.{}".format(outer.name, name))
         self.elemtype = elemtype
 
-    def val_from_str(self, s):
+    def val_from_str(self, s: str) -> Tuple[List[Any], str]:
         # Simple arrays of bytes don't need commas
         if self.elemtype.name == 'byte':
             a, b = split_field(s)
@@ -30,20 +34,20 @@ wants an array of some type.
                 s = s[1:]
         return ret, s[1:]
 
-    def val_to_str(self, v, otherfields):
+    def val_to_str(self, v: List[Any], otherfields: Dict[str, Any]) -> str:
         if self.elemtype.name == 'byte':
             return bytes(v).hex()
 
         s = ','.join(self.elemtype.val_to_str(i, otherfields) for i in v)
         return '[' + s + ']'
 
-    def write(self, io_out, v, otherfields):
+    def write(self, io_out: BufferedIOBase, v: List[Any], otherfields: Dict[str, Any]) -> None:
         for i in v:
             self.elemtype.write(io_out, i, otherfields)
 
-    def read_arr(self, io_in, otherfields, arraysize):
+    def read_arr(self, io_in: BufferedIOBase, otherfields: Dict[str, Any], arraysize: Optional[int]) -> List[Any]:
         """arraysize None means take rest of io entirely and exactly"""
-        vals = []
+        vals: List[Any] = []
         while arraysize is None or len(vals) < arraysize:
             # Throws an exception on partial read, so None means completely empty.
             val = self.elemtype.read(io_in, otherfields)
@@ -60,65 +64,65 @@ wants an array of some type.
 
 class SizedArrayType(ArrayType):
     """A fixed-size array"""
-    def __init__(self, outer, name, elemtype, arraysize):
+    def __init__(self, outer: 'SubtypeType', name: str, elemtype: FieldType, arraysize: int):
         super().__init__(outer, name, elemtype)
         self.arraysize = arraysize
 
-    def val_to_str(self, v, otherfields):
+    def val_to_str(self, v: List[Any], otherfields: Dict[str, Any]) -> str:
         if len(v) != self.arraysize:
             raise ValueError("Length of {} != {}", v, self.arraysize)
         return super().val_to_str(v, otherfields)
 
-    def val_from_str(self, s):
+    def val_from_str(self, s: str) -> Tuple[List[Any], str]:
         a, b = super().val_from_str(s)
         if len(a) != self.arraysize:
             raise ValueError("Length of {} != {}", s, self.arraysize)
         return a, b
 
-    def write(self, io_out, v, otherfields):
+    def write(self, io_out: BufferedIOBase, v: List[Any], otherfields: Dict[str, Any]) -> None:
         if len(v) != self.arraysize:
             raise ValueError("Length of {} != {}", v, self.arraysize)
         return super().write(io_out, v, otherfields)
 
-    def read(self, io_in, otherfields):
+    def read(self, io_in: BufferedIOBase, otherfields: Dict[str, Any]) -> List[Any]:
         return super().read_arr(io_in, otherfields, self.arraysize)
 
 
 class EllipsisArrayType(ArrayType):
     """This is used for ... fields at the end of a tlv: the array ends
 when the tlv ends"""
-    def __init__(self, tlv, name, elemtype):
+    def __init__(self, tlv: 'TlvStreamType', name: str, elemtype: FieldType):
         super().__init__(tlv, name, elemtype)
 
-    def read(self, io_in, otherfields):
+    def read(self, io_in: BufferedIOBase, otherfields: Dict[str, Any]) -> List[Any]:
         """Takes rest of bytestream"""
         return super().read_arr(io_in, otherfields, None)
 
-    def only_at_tlv_end(self):
+    def only_at_tlv_end(self) -> bool:
         """These only make sense at the end of a TLV"""
         return True
 
 
 class LengthFieldType(FieldType):
     """Special type to indicate this serves as a length field for others"""
-    def __init__(self, inttype):
+    def __init__(self, inttype: IntegerType):
         if type(inttype) is not IntegerType:
             raise ValueError("{} cannot be a length; not an integer!"
                              .format(self.name))
         super().__init__(inttype.name)
         self.underlying_type = inttype
         # You can be length for more than one field!
-        self.len_for = []
+        self.len_for: List[DynamicArrayType] = []
 
-    def is_optional(self):
+    def is_optional(self) -> bool:
         """This field value is always implies, never specified directly"""
         return True
 
-    def add_length_for(self, field):
+    def add_length_for(self, field: 'DynamicArrayType') -> None:
         assert isinstance(field.fieldtype, DynamicArrayType)
         self.len_for.append(field)
 
-    def calc_value(self, otherfields):
+    def calc_value(self, otherfields: Dict[str, Any]) -> int:
         """Calculate length value from field(s) themselves"""
         if self.len_fields_bad('', otherfields):
             raise ValueError("Lengths of fields {} not equal!"
@@ -126,7 +130,7 @@ class LengthFieldType(FieldType):
 
         return len(otherfields[self.len_for[0].name])
 
-    def _maybe_calc_value(self, fieldname, otherfields):
+    def _maybe_calc_value(self, fieldname: str, otherfields: Dict[str, Any]) -> int:
         # Perhaps we're just demarshalling from binary now, so we actually
         # stored it.  Remove, and we'll calc from now on.
         if fieldname in otherfields:
@@ -135,27 +139,27 @@ class LengthFieldType(FieldType):
             return v
         return self.calc_value(otherfields)
 
-    def val_to_str(self, _, otherfields):
+    def val_to_str(self, _, otherfields: Dict[str, Any]) -> str:
         return self.underlying_type.val_to_str(self.calc_value(otherfields),
                                                otherfields)
 
-    def name_and_val(self, name, v):
+    def name_and_val(self, name: str, v: int) -> str:
         """We don't print out length fields when printing out messages:
 they're implied by the length of other fields"""
         return ''
 
-    def read(self, io_in, otherfields):
+    def read(self, io_in: BufferedIOBase, otherfields: Dict[str, Any]) -> None:
         """We store this, but it'll be removed from the fields as soon as it's used (i.e. by DynamicArrayType's val_from_bin)"""
         return self.underlying_type.read(io_in, otherfields)
 
-    def write(self, io_out, _, otherfields):
+    def write(self, io_out: BufferedIOBase, _, otherfields: Dict[str, Any]) -> None:
         self.underlying_type.write(io_out, self.calc_value(otherfields),
                                    otherfields)
 
-    def val_from_str(self, s):
+    def val_from_str(self, s: str):
         raise ValueError('{} is implied, cannot be specified'.format(self))
 
-    def len_fields_bad(self, fieldname, otherfields):
+    def len_fields_bad(self, fieldname: str, otherfields: Dict[str, Any]) -> List[str]:
         """fieldname is the name to return if this length is bad"""
         mylen = None
         for lens in self.len_for:
@@ -170,11 +174,11 @@ they're implied by the length of other fields"""
 
 class DynamicArrayType(ArrayType):
     """This is used for arrays where another field controls the size"""
-    def __init__(self, outer, name, elemtype, lenfield):
+    def __init__(self, outer: 'SubtypeType', name: str, elemtype: FieldType, lenfield: LengthFieldType):
         super().__init__(outer, name, elemtype)
         assert type(lenfield.fieldtype) is LengthFieldType
         self.lenfield = lenfield
 
-    def read(self, io_in, otherfields):
+    def read(self, io_in: BufferedIOBase, otherfields: Dict[str, Any]) -> List[Any]:
         return super().read_arr(io_in, otherfields,
                                 self.lenfield.fieldtype._maybe_calc_value(self.lenfield.name, otherfields))

contrib/pyln-proto/pyln/proto/message/fundamental_types.py

@@ -1,11 +1,11 @@
 import struct
-import io
+from io import BufferedIOBase
 import sys
-from typing import Optional
+from typing import Dict, Optional, Tuple, List, Any
 
 
 def try_unpack(name: str,
-               io_out: io.BufferedIOBase,
+               io_out: BufferedIOBase,
                structfmt: str,
                empty_ok: bool) -> Optional[int]:
     """Unpack a single value using struct.unpack.
@@ -20,7 +20,7 @@ If need_all, never return None, otherwise returns None if EOF."""
     return struct.unpack(structfmt, b)[0]
 
 
-def split_field(s):
+def split_field(s: str) -> Tuple[str, str]:
     """Helper to split string into first part and remainder"""
     def len_without(s, delim):
         pos = s.find(delim)
@@ -37,25 +37,28 @@ class FieldType(object):
 These are further specialized.
 
     """
-    def __init__(self, name):
+    def __init__(self, name: str):
         self.name = name
 
-    def only_at_tlv_end(self):
+    def only_at_tlv_end(self) -> bool:
         """Some types only make sense inside a tlv, at the end"""
         return False
 
-    def name_and_val(self, name, v):
+    def name_and_val(self, name: str, v: Any) -> str:
         """This is overridden by LengthFieldType to return nothing"""
-        return " {}={}".format(name, self.val_to_str(v, None))
+        return " {}={}".format(name, self.val_to_str(v, {}))
 
-    def is_optional(self):
+    def is_optional(self) -> bool:
         """Overridden for tlv fields and optional fields"""
         return False
 
-    def len_fields_bad(self, fieldname, fieldvals):
+    def len_fields_bad(self, fieldname: str, fieldvals: Dict[str, Any]) -> List[str]:
         """Overridden by length fields for arrays"""
         return []
 
+    def val_to_str(self, v: Any, otherfields: Dict[str, Any]) -> str:
+        raise NotImplementedError()
+
     def __str__(self):
         return self.name
 
@@ -64,22 +67,22 @@ These are further specialized.
 
 
 class IntegerType(FieldType):
-    def __init__(self, name, bytelen, structfmt):
+    def __init__(self, name: str, bytelen: int, structfmt: str):
         super().__init__(name)
         self.bytelen = bytelen
         self.structfmt = structfmt
 
-    def val_to_str(self, v, otherfields):
+    def val_to_str(self, v: int, otherfields: Dict[str, Any]):
         return "{}".format(int(v))
 
-    def val_from_str(self, s):
+    def val_from_str(self, s: str) -> Tuple[int, str]:
         a, b = split_field(s)
         return int(a), b
 
-    def write(self, io_out, v, otherfields):
+    def write(self, io_out: BufferedIOBase, v: int, otherfields: Dict[str, Any]) -> None:
         io_out.write(struct.pack(self.structfmt, v))
 
-    def read(self, io_in, otherfields):
+    def read(self, io_in: BufferedIOBase, otherfields: Dict[str, Any]) -> Optional[int]:
         return try_unpack(self.name, io_in, self.structfmt, empty_ok=True)
 
 
@@ -91,11 +94,11 @@ basically a u64.
     def __init__(self, name):
         super().__init__(name, 8, '>Q')
 
-    def val_to_str(self, v, otherfields):
+    def val_to_str(self, v: int, otherfields: Dict[str, Any]) -> str:
         # See BOLT #7: ## Definition of `short_channel_id`
         return "{}x{}x{}".format(v >> 40, (v >> 16) & 0xFFFFFF, v & 0xFFFF)
 
-    def val_from_str(self, s):
+    def val_from_str(self, s: str) -> Tuple[int, str]:
         a, b = split_field(s)
         parts = a.split('x')
         if len(parts) != 3:
@@ -107,25 +110,25 @@ basically a u64.
 
 class TruncatedIntType(FieldType):
     """Truncated integer types"""
-    def __init__(self, name, maxbytes):
+    def __init__(self, name: str, maxbytes: int):
         super().__init__(name)
         self.maxbytes = maxbytes
 
-    def val_to_str(self, v, otherfields):
+    def val_to_str(self, v: int, otherfields: Dict[str, Any]) -> str:
         return "{}".format(int(v))
 
-    def only_at_tlv_end(self):
+    def only_at_tlv_end(self) -> bool:
         """These only make sense at the end of a TLV"""
         return True
 
-    def val_from_str(self, s):
+    def val_from_str(self, s: str) -> Tuple[int, str]:
         a, b = split_field(s)
         if int(a) >= (1 << (self.maxbytes * 8)):
             raise ValueError('{} exceeds maximum {} capacity'
                              .format(a, self.name))
         return int(a), b
 
-    def write(self, io_out, v, otherfields):
+    def write(self, io_out: BufferedIOBase, v: int, otherfields: Dict[str, Any]) -> None:
         binval = struct.pack('>Q', v)
         while len(binval) != 0 and binval[0] == 0:
             binval = binval[1:]
@@ -134,41 +137,41 @@ class TruncatedIntType(FieldType):
                              .format(v, self.name))
         io_out.write(binval)
 
-    def read(self, io_in, otherfields):
+    def read(self, io_in: BufferedIOBase, otherfields: Dict[str, Any]) -> None:
         binval = io_in.read()
         if len(binval) > self.maxbytes:
-            raise ValueError('{} is too long for {}'.format(binval, self.name))
+            raise ValueError('{} is too long for {}'.format(binval.hex(), self.name))
         if len(binval) > 0 and binval[0] == 0:
             raise ValueError('{} encoding is not minimal: {}'
-                             .format(self.name, binval))
+                             .format(self.name, binval.hex()))
         # Pad with zeroes and convert as u64
         return struct.unpack_from('>Q', bytes(8 - len(binval)) + binval)[0]
 
 
 class FundamentalHexType(FieldType):
     """The remaining fundamental types are simply represented as hex strings"""
-    def __init__(self, name, bytelen):
+    def __init__(self, name: str, bytelen: int):
         super().__init__(name)
         self.bytelen = bytelen
 
-    def val_to_str(self, v, otherfields):
+    def val_to_str(self, v: bytes, otherfields: Dict[str, Any]) -> str:
         if len(bytes(v)) != self.bytelen:
             raise ValueError("Length of {} != {}", v, self.bytelen)
         return v.hex()
 
-    def val_from_str(self, s):
+    def val_from_str(self, s: str) -> Tuple[bytes, str]:
         a, b = split_field(s)
         ret = bytes.fromhex(a)
         if len(ret) != self.bytelen:
             raise ValueError("Length of {} != {}", a, self.bytelen)
         return ret, b
 
-    def write(self, io_out, v, otherfields):
+    def write(self, io_out: BufferedIOBase, v: bytes, otherfields: Dict[str, Any]) -> None:
         if len(bytes(v)) != self.bytelen:
             raise ValueError("Length of {} != {}", v, self.bytelen)
         io_out.write(v)
 
-    def read(self, io_in, otherfields):
+    def read(self, io_in: BufferedIOBase, otherfields: Dict[str, Any]) -> Optional[bytes]:
         val = io_in.read(self.bytelen)
         if len(val) == 0:
             return None
@@ -182,13 +185,13 @@ class BigSizeType(FieldType):
     def __init__(self, name):
         super().__init__(name)
 
-    def val_from_str(self, s):
+    def val_from_str(self, s: str) -> Tuple[int, str]:
         a, b = split_field(s)
         return int(a), b
 
     # For the convenience of TLV header parsing
     @staticmethod
-    def write(io_out, v, otherfields=None):
+    def write(io_out: BufferedIOBase, v: int, otherfields: Dict[str, Any] = {}) -> None:
         if v < 253:
             io_out.write(bytes([v]))
         elif v < 2**16:
@@ -199,7 +202,7 @@ class BigSizeType(FieldType):
             io_out.write(bytes([255]) + struct.pack('>Q', v))
 
     @staticmethod
-    def read(io_in, otherfields=None):
+    def read(io_in: BufferedIOBase, otherfields: Dict[str, Any] = {}) -> Optional[int]:
         "Returns value, or None on EOF"
         b = io_in.read(1)
         if len(b) == 0:
@@ -213,7 +216,7 @@ class BigSizeType(FieldType):
         else:
             return try_unpack('BigSize', io_in, '>Q', empty_ok=False)
 
-    def val_to_str(self, v, otherfields):
+    def val_to_str(self, v: int, otherfields: Dict[str, Any]) -> str:
         return "{}".format(int(v))
 
 

contrib/pyln-proto/pyln/proto/message/message.py

@@ -1,19 +1,20 @@
 import struct
-import io
-from .fundamental_types import fundamental_types, BigSizeType, split_field, try_unpack
+from io import BufferedIOBase, BytesIO
+from .fundamental_types import fundamental_types, BigSizeType, split_field, try_unpack, FieldType
 from .array_types import (
     SizedArrayType, DynamicArrayType, LengthFieldType, EllipsisArrayType
 )
+from typing import Dict, List, Optional, Tuple, Any, cast
 
 
 class MessageNamespace(object):
     """A class which contains all FieldTypes and Messages in a particular
 domain, such as within a given BOLT"""
-    def __init__(self, csv_lines=[]):
-        self.subtypes = {}
-        self.fundamentaltypes = {}
-        self.tlvtypes = {}
-        self.messagetypes = {}
+    def __init__(self, csv_lines: List[str] = []):
+        self.subtypes: Dict[str, SubtypeType] = {}
+        self.fundamentaltypes: Dict[str, SubtypeType] = {}
+        self.tlvtypes: Dict[str, TlvStreamType] = {}
+        self.messagetypes: Dict[str, MessageType] = {}
 
         # For convenience, basic types go in every namespace
         for t in fundamental_types():
@@ -21,7 +22,7 @@ domain, such as within a given BOLT"""
 
         self.load_csv(csv_lines)
 
-    def __add__(self, other):
+    def __add__(self, other: 'MessageNamespace'):
         ret = MessageNamespace()
         ret.subtypes = self.subtypes.copy()
         for v in other.subtypes.values():
@@ -34,57 +35,57 @@ domain, such as within a given BOLT"""
             ret.add_messagetype(v)
         return ret
 
-    def add_subtype(self, t):
+    def add_subtype(self, t: 'SubtypeType') -> None:
         prev = self.get_type(t.name)
         if prev:
-            return ValueError('Already have {}'.format(prev))
+            raise ValueError('Already have {}'.format(prev))
         self.subtypes[t.name] = t
 
-    def add_fundamentaltype(self, t):
+    def add_fundamentaltype(self, t: 'SubtypeType') -> None:
         assert not self.get_type(t.name)
         self.fundamentaltypes[t.name] = t
 
-    def add_tlvtype(self, t):
+    def add_tlvtype(self, t: 'TlvStreamType') -> None:
         prev = self.get_type(t.name)
         if prev:
-            return ValueError('Already have {}'.format(prev))
+            raise ValueError('Already have {}'.format(prev))
         self.tlvtypes[t.name] = t
 
-    def add_messagetype(self, m):
+    def add_messagetype(self, m: 'MessageType') -> None:
         if self.get_msgtype(m.name):
-            return ValueError('{}: message already exists'.format(m.name))
+            raise ValueError('{}: message already exists'.format(m.name))
         if self.get_msgtype_by_number(m.number):
-            return ValueError('{}: message {} already number {}'.format(
-                m.name, self.get_msg_by_number(m.number), m.number))
+            raise ValueError('{}: message {} already number {}'.format(
+                m.name, self.get_msgtype_by_number(m.number), m.number))
         self.messagetypes[m.name] = m
 
-    def get_msgtype(self, name):
+    def get_msgtype(self, name: str) -> Optional['MessageType']:
         if name in self.messagetypes:
             return self.messagetypes[name]
         return None
 
-    def get_msgtype_by_number(self, num):
+    def get_msgtype_by_number(self, num: int) -> Optional['MessageType']:
         for m in self.messagetypes.values():
             if m.number == num:
                 return m
         return None
 
-    def get_fundamentaltype(self, name):
+    def get_fundamentaltype(self, name: str) -> Optional['SubtypeType']:
         if name in self.fundamentaltypes:
             return self.fundamentaltypes[name]
         return None
 
-    def get_subtype(self, name):
+    def get_subtype(self, name: str) -> Optional['SubtypeType']:
         if name in self.subtypes:
             return self.subtypes[name]
         return None
 
-    def get_tlvtype(self, name):
+    def get_tlvtype(self, name: str) -> Optional['TlvStreamType']:
         if name in self.tlvtypes:
             return self.tlvtypes[name]
         return None
 
-    def get_type(self, name):
+    def get_type(self, name: str) -> Optional['SubtypeType']:
         t = self.get_fundamentaltype(name)
         if t is None:
             t = self.get_subtype(name)
@@ -92,15 +93,9 @@ domain, such as within a given BOLT"""
             t = self.get_tlvtype(name)
         return t
 
-    def get_tlv_by_number(self, num):
-        for t in self.tlvtypes:
-            if t.number == num:
-                return t
-        return None
-
-    def load_csv(self, lines):
+    def load_csv(self, lines: List[str]) -> None:
         """Load a series of comma-separate-value lines into the namespace"""
-        vals = {'msgtype': [],
+        vals: Dict[str, List[List[str]]] = {'msgtype': [],
                                             'msgdata': [],
                                             'tlvtype': [],
                                             'tlvdata': [],
@@ -114,39 +109,39 @@ domain, such as within a given BOLT"""
 
         # Types can refer to other types, so add data last.
         for parts in vals['msgtype']:
-            self.add_messagetype(MessageType.type_from_csv(parts))
+            self.add_messagetype(MessageType.msgtype_from_csv(parts))
 
         for parts in vals['subtype']:
-            self.add_subtype(SubtypeType.type_from_csv(parts))
+            self.add_subtype(SubtypeType.subtype_from_csv(parts))
 
         for parts in vals['tlvtype']:
-            TlvStreamType.type_from_csv(self, parts)
+            TlvStreamType.tlvtype_from_csv(self, parts)
 
         for parts in vals['msgdata']:
-            MessageType.field_from_csv(self, parts)
+            MessageType.msgfield_from_csv(self, parts)
 
         for parts in vals['subtypedata']:
-            SubtypeType.field_from_csv(self, parts)
+            SubtypeType.subfield_from_csv(self, parts)
 
         for parts in vals['tlvdata']:
-            TlvStreamType.field_from_csv(self, parts)
+            TlvStreamType.tlvfield_from_csv(self, parts)
 
 
 class MessageTypeField(object):
     """A field within a particular message type or subtype"""
-    def __init__(self, ownername, name, fieldtype, option=None):
+    def __init__(self, ownername: str, name: str, fieldtype: FieldType, option: Optional[str] = None):
         self.full_name = "{}.{}".format(ownername, name)
         self.name = name
         self.fieldtype = fieldtype
         self.option = option
 
-    def missing_fields(self, fields):
+    def missing_fields(self, fieldvals: Dict[str, Any]):
         """Return this field if it's not in fields"""
-        if self.name not in fields and not self.option and not self.fieldtype.is_optional():
+        if self.name not in fieldvals and not self.option and not self.fieldtype.is_optional():
             return [self]
         return []
 
-    def len_fields_bad(self, fieldname, otherfields):
+    def len_fields_bad(self, fieldname: str, otherfields: Dict[str, Any]) -> List[str]:
         return self.fieldtype.len_fields_bad(fieldname, otherfields)
 
     def __str__(self):
@@ -163,17 +158,17 @@ other types.  Since 'msgtype' and 'tlvtype' are almost identical, they
 inherit from this too.
 
     """
-    def __init__(self, name):
+    def __init__(self, name: str):
         self.name = name
-        self.fields = []
+        self.fields: List[FieldType] = []
 
-    def find_field(self, fieldname):
+    def find_field(self, fieldname: str):
         for f in self.fields:
             if f.name == fieldname:
                 return f
         return None
 
-    def add_field(self, field):
+    def add_field(self, field: FieldType):
         if self.find_field(field.name):
             raise ValueError("{}: duplicate field {}".format(self, field))
         self.fields.append(field)
@@ -181,8 +176,8 @@ inherit from this too.
     def __str__(self):
         return "subtype-{}".format(self.name)
 
-    def len_fields_bad(self, fieldname, otherfields):
-        bad_fields = []
+    def len_fields_bad(self, fieldname: str, otherfields: Dict[str, Any]) -> List[str]:
+        bad_fields: List[str] = []
         for f in self.fields:
             bad_fields += f.len_fields_bad('{}.{}'.format(fieldname, f.name),
                                            otherfields)
@@ -190,14 +185,14 @@ inherit from this too.
         return bad_fields
 
     @staticmethod
-    def type_from_csv(parts):
+    def subtype_from_csv(parts: List[str]) -> 'SubtypeType':
         """e.g subtype,channel_update_timestamps"""
         if len(parts) != 1:
             raise ValueError("subtype expected 2 CSV parts, not {}"
                              .format(parts))
         return SubtypeType(parts[0])
 
-    def _field_from_csv(self, namespace, parts, ellipsisok=False, option=None):
+    def _field_from_csv(self, namespace: MessageNamespace, parts: List[str], ellipsisok=False, option: str = None) -> MessageTypeField:
         """Takes msgdata/subtypedata after first two fields
         e.g. [...]timestamp_node_id_1,u32,
 
@@ -236,12 +231,12 @@ inherit from this too.
 
         return field
 
-    def val_from_str(self, s):
+    def val_from_str(self, s: str) -> Tuple[Dict[str, Any], str]:
         if not s.startswith('{'):
             raise ValueError("subtype {} must be wrapped in '{{}}': bad {}"
                              .format(self, s))
         s = s[1:]
-        ret = {}
+        ret: Dict[str, Any] = {}
         # FIXME: perhaps allow unlabelled fields to imply assign fields in order?
         while not s.startswith('}'):
             fieldname, s = s.split('=', 1)
@@ -259,7 +254,7 @@ inherit from this too.
 
         return ret, s[1:]
 
-    def _raise_if_badvals(self, v):
+    def _raise_if_badvals(self, v: Dict[str, Any]) -> None:
         # Every non-optional value must be specified, and no others.
         defined = set([f.name for f in self.fields])
         have = set(v)
@@ -272,7 +267,7 @@ inherit from this too.
             if not f.fieldtype.is_optional():
                 raise ValueError("Missing value for {}".format(f))
 
-    def val_to_str(self, v, otherfields):
+    def val_to_str(self, v: Dict[str, Any], otherfields: Dict[str, Any]) -> str:
         self._raise_if_badvals(v)
         s = ''
         sep = ''
@@ -283,13 +278,13 @@ inherit from this too.
 
         return '{' + s + '}'
 
-    def write(self, io_out, v, otherfields):
+    def write(self, io_out: BufferedIOBase, v: Dict[str, Any], otherfields: Dict[str, Any]) -> None:
         self._raise_if_badvals(v)
         for fname, val in v.items():
             field = self.find_field(fname)
             field.fieldtype.write(io_out, val, otherfields)
 
-    def read(self, io_in, otherfields):
+    def read(self, io_in: BufferedIOBase, otherfields: Dict[str, Any]) -> Dict[str, Any]:
         vals = {}
         for field in self.fields:
             val = field.fieldtype.read(io_in, otherfields)
@@ -302,7 +297,7 @@ inherit from this too.
         return vals
 
     @staticmethod
-    def field_from_csv(namespace, parts):
+    def subfield_from_csv(namespace: MessageNamespace, parts: List[str]) -> None:
         """e.g
 subtypedata,channel_update_timestamps,timestamp_node_id_1,u32,"""
         if len(parts) != 4:
@@ -330,12 +325,12 @@ class MessageType(SubtypeType):
                    'NODE': 0x2000,
                    'UPDATE': 0x1000}
 
-    def __init__(self, name, value, option=None):
+    def __init__(self, name: str, value: str, option: Optional[str] = None):
         super().__init__(name)
         self.number = self.parse_value(value)
         self.option = option
 
-    def parse_value(self, value):
+    def parse_value(self, value: str) -> int:
         result = 0
         for token in value.split('|'):
             if token in self.onion_types.keys():
@@ -349,7 +344,7 @@ class MessageType(SubtypeType):
         return "msgtype-{}".format(self.name)
 
     @staticmethod
-    def type_from_csv(parts):
+    def msgtype_from_csv(parts: List[str]) -> 'MessageType':
         """e.g msgtype,open_channel,32,option_foo"""
         option = None
         if len(parts) == 3:
@@ -360,7 +355,7 @@ class MessageType(SubtypeType):
         return MessageType(parts[0], parts[1], option)
 
     @staticmethod
-    def field_from_csv(namespace, parts):
+    def msgfield_from_csv(namespace: MessageNamespace, parts: List[str]) -> None:
         """e.g msgdata,open_channel,temporary_channel_id,byte,32[,opt]"""
         option = None
         if len(parts) == 5:
@@ -390,18 +385,18 @@ confusingly) refers to them.
     def __str__(self):
         return "tlvstreamtype-{}".format(self.name)
 
-    def find_field_by_number(self, num):
+    def find_field_by_number(self, num: int) -> Optional['TlvMessageType']:
         for f in self.fields:
             if f.number == num:
                 return f
         return None
 
-    def is_optional(self):
+    def is_optional(self) -> bool:
         """You can omit a tlvstream= altogether"""
         return True
 
     @staticmethod
-    def type_from_csv(namespace, parts):
+    def tlvtype_from_csv(namespace: MessageNamespace, parts: List[str]) -> None:
         """e.g tlvtype,reply_channel_range_tlvs,timestamps_tlv,1"""
         if len(parts) != 3:
             raise ValueError("tlvtype expected 4 CSV parts, not {}"
@@ -414,7 +409,7 @@ confusingly) refers to them.
         tlvstream.add_field(TlvMessageType(parts[1], parts[2]))
 
     @staticmethod
-    def field_from_csv(namespace, parts):
+    def tlvfield_from_csv(namespace: MessageNamespace, parts: List[str]) -> None:
         """e.g
 tlvdata,reply_channel_range_tlvs,timestamps_tlv,encoding_type,u8,
 
@@ -435,20 +430,21 @@ tlvdata,reply_channel_range_tlvs,timestamps_tlv,encoding_type,u8,
         subfield = field._field_from_csv(namespace, parts[2:], ellipsisok=True)
         field.add_field(subfield)
 
-    def val_from_str(self, s):
+    def val_from_str(self, s: str) -> Tuple[Dict[str, Any], str]:
         """{fieldname={...},...}.  Returns dict of fieldname->val"""
         if not s.startswith('{'):
             raise ValueError("tlvtype {} must be wrapped in '{{}}': bad {}"
                              .format(self, s))
         s = s[1:]
-        ret = {}
+        ret: Dict[str, Any] = {}
         while not s.startswith('}'):
             fieldname, s = s.split('=', 1)
             f = self.find_field(fieldname)
             if f is None:
                 # Unknown fields are number=hexstring
                 hexstring, s = split_field(s)
-                ret[int(fieldname)] = bytes.fromhex(hexstring)
+                # Make sure it is actually a valid int!
+                ret[str(int(fieldname))] = bytes.fromhex(hexstring)
             else:
                 ret[fieldname], s = f.val_from_str(s)
             if s[0] == ',':
@@ -456,7 +452,7 @@ tlvdata,reply_channel_range_tlvs,timestamps_tlv,encoding_type,u8,
 
         return ret, s[1:]
 
-    def val_to_str(self, v, otherfields):
+    def val_to_str(self, v: Dict[str, Any], otherfields: Dict[str, Any]) -> str:
         s = ''
         sep = ''
         for fieldname in v:
@@ -470,14 +466,14 @@ tlvdata,reply_channel_range_tlvs,timestamps_tlv,encoding_type,u8,
 
         return '{' + s + '}'
 
-    def write(self, iobuf, v, otherfields):
+    def write(self, io_out: BufferedIOBase, v: Optional[Dict[str, Any]], otherfields: Dict[str, Any]) -> None:
         # If they didn't specify this tlvstream, it's empty.
         if v is None:
             return
 
         # Make a tuple of (fieldnum, val_to_bin, val) so we can sort into
         # ascending order as TLV spec requires.
-        def write_raw_val(iobuf, val, otherfields):
+        def write_raw_val(iobuf, val, otherfields: Dict[str, Any]):
             iobuf.write(val)
 
         def get_value(tup):
@@ -496,14 +492,14 @@ tlvdata,reply_channel_range_tlvs,timestamps_tlv,encoding_type,u8,
         ordered.sort(key=get_value)
 
         for typenum, writefunc, val in ordered:
-            buf = io.BytesIO()
+            buf = BytesIO()
             writefunc(buf, val, otherfields)
-            BigSizeType.write(iobuf, typenum)
-            BigSizeType.write(iobuf, len(buf.getvalue()))
-            iobuf.write(buf.getvalue())
+            BigSizeType.write(io_out, typenum)
+            BigSizeType.write(io_out, len(buf.getvalue()))
+            io_out.write(buf.getvalue())
 
-    def read(self, io_in, otherfields):
-        vals = {}
+    def read(self, io_in: BufferedIOBase, otherfields: Dict[str, Any]) -> Dict[str, Any]:
+        vals: Dict[str, Any] = {}
 
         while True:
             tlv_type = BigSizeType.read(io_in)
@@ -522,17 +518,18 @@ tlvdata,reply_channel_range_tlvs,timestamps_tlv,encoding_type,u8,
                 # Raw fields are allowed, just index by number.
                 vals[tlv_type] = binval
             else:
-                vals[f.name] = f.read(io.BytesIO(binval), otherfields)
+                # FIXME: Why doesn't mypy think BytesIO is a valid BufferedIOBase?
+                vals[f.name] = f.read(cast(BufferedIOBase, BytesIO(binval)), otherfields)
 
-    def name_and_val(self, name, v):
+    def name_and_val(self, name: str, v: Dict[str, Any]) -> str:
         """This is overridden by LengthFieldType to return nothing"""
-        return " {}={}".format(name, self.val_to_str(v, None))
+        return " {}={}".format(name, self.val_to_str(v, {}))
 
 
 class TlvMessageType(MessageType):
     """A 'tlvtype' in BOLT-speak"""
 
-    def __init__(self, name, value):
+    def __init__(self, name: str, value: str):
         super().__init__(name, value)
 
     def __str__(self):
@@ -541,10 +538,10 @@ class TlvMessageType(MessageType):
 
 class Message(object):
     """A particular message instance"""
-    def __init__(self, messagetype, **kwargs):
+    def __init__(self, messagetype: MessageType, **kwargs):
         """MessageType is the type of this msg, with fields.  Fields can either be valid values for the type, or if they are strings they are converted according to the field type"""
         self.messagetype = messagetype
-        self.fields = {}
+        self.fields: Dict[str, Any] = {}
 
         # Convert arguments from strings to values if necessary.
         for field in kwargs:
@@ -564,16 +561,16 @@ class Message(object):
         if bad_lens:
             raise ValueError("Inconsistent length fields: {}".format(bad_lens))
 
-    def missing_fields(self):
+    def missing_fields(self) -> List[str]:
         """Are any required fields missing?"""
-        missing = []
+        missing: List[str] = []
         for ftype in self.messagetype.fields:
             missing += ftype.missing_fields(self.fields)
 
         return missing
 
     @staticmethod
-    def read(namespace, io_in):
+    def read(namespace: MessageNamespace, io_in: BufferedIOBase) -> Optional['Message']:
         """Read and decode a Message within that namespace.
 
 Returns None on EOF
@@ -587,7 +584,7 @@ Returns None on EOF
         if mtype is None:
             raise ValueError('Unknown message type number {}'.format(typenum))
 
-        fields = {}
+        fields: Dict[str, Any] = {}
         for f in mtype.fields:
             fields[f.name] = f.fieldtype.read(io_in, fields)
             if fields[f.name] is None:
@@ -598,7 +595,7 @@ Returns None on EOF
         return Message(mtype, **fields)
 
     @staticmethod
-    def from_str(namespace, s, incomplete_ok=False):
+    def from_str(namespace: MessageNamespace, s: str, incomplete_ok=False) -> 'Message':
         """Decode a string to a Message within that namespace.
 
 Format is msgname [ field=...]*.
@@ -624,7 +621,7 @@ Format is msgname [ field=...]*.
 
         return m
 
-    def write(self, io_out):
+    def write(self, io_out: BufferedIOBase) -> None:
         """Write a Message into its wire format.
 
 Must not have missing fields.
@@ -645,7 +642,7 @@ Must not have missing fields.
                 val = None
             f.fieldtype.write(io_out, val, self.fields)
 
-    def to_str(self):
+    def to_str(self) -> str:
         """Encode a Message into a string"""
         ret = "{}".format(self.messagetype.name)
         for f in self.messagetype.fields: