Allow(unused_imports) on prelude imports
[rust-lightning] / lightning / src / util / ser_macros.rs
index 0a5c0b643dd0c315f2782d94b7caa469dcf4e46d..312fe7d9f98424ea2a0ad3dc3231cd765d50e624 100644 (file)
 //! [`Readable`]: crate::util::ser::Readable
 //! [`Writeable`]: crate::util::ser::Writeable
 
+// There are quite a few TLV serialization "types" which behave differently. We currently only
+// publicly document the `optional` and `required` types, not supporting anything else publicly and
+// changing them at will.
+//
+// Some of the other types include:
+//  * (default_value, $default) - reads optionally, reading $default if no TLV is present
+//  * (static_value, $value) - ignores any TLVs, always using $value
+//  * required_vec - reads into a Vec without a length prefix, failing if no TLV is present.
+//  * optional_vec - reads into an Option<Vec> without a length prefix, continuing if no TLV is
+//                   present. Writes from a Vec directly, only if any elements are present. Note
+//                   that the struct deserialization macros return a Vec, not an Option.
+//  * upgradable_option - reads via MaybeReadable.
+//  * upgradable_required - reads via MaybeReadable, requiring a TLV be present but may return None
+//                          if MaybeReadable::read() returns None.
+
 /// Implements serialization for a single TLV record.
 /// This is exported for use by other exported macros, do not use directly.
 #[doc(hidden)]
@@ -29,7 +44,7 @@ macro_rules! _encode_tlv {
                BigSize($field.serialized_length() as u64).write($stream)?;
                $field.write($stream)?;
        };
-       ($stream: expr, $type: expr, $field: expr, vec_type) => {
+       ($stream: expr, $type: expr, $field: expr, required_vec) => {
                $crate::_encode_tlv!($stream, $type, $crate::util::ser::WithoutLength(&$field), required);
        };
        ($stream: expr, $optional_type: expr, $optional_field: expr, option) => {
@@ -39,15 +54,27 @@ macro_rules! _encode_tlv {
                        field.write($stream)?;
                }
        };
-       ($stream: expr, $type: expr, $field: expr, ignorable) => {
+       ($stream: expr, $type: expr, $field: expr, optional_vec) => {
+               if !$field.is_empty() {
+                       $crate::_encode_tlv!($stream, $type, $field, required_vec);
+               }
+       };
+       ($stream: expr, $type: expr, $field: expr, upgradable_required) => {
                $crate::_encode_tlv!($stream, $type, $field, required);
        };
+       ($stream: expr, $type: expr, $field: expr, upgradable_option) => {
+               $crate::_encode_tlv!($stream, $type, $field, option);
+       };
        ($stream: expr, $type: expr, $field: expr, (option, encoding: ($fieldty: ty, $encoding: ident))) => {
                $crate::_encode_tlv!($stream, $type, $field.map(|f| $encoding(f)), option);
        };
        ($stream: expr, $type: expr, $field: expr, (option, encoding: $fieldty: ty)) => {
                $crate::_encode_tlv!($stream, $type, $field, option);
        };
+       ($stream: expr, $type: expr, $field: expr, (option: $trait: ident $(, $read_arg: expr)?)) => {
+               // Just a read-mapped type
+               $crate::_encode_tlv!($stream, $type, $field, option);
+       };
 }
 
 /// Panics if the last seen TLV type is not numerically less than the TLV type currently being checked.
@@ -105,7 +132,20 @@ macro_rules! _check_encoded_tlv_order {
 /// [`Writer`]: crate::util::ser::Writer
 #[macro_export]
 macro_rules! encode_tlv_stream {
+       ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}) => {
+               $crate::_encode_tlv_stream!($stream, {$(($type, $field, $fieldty)),*})
+       }
+}
+
+/// Implementation of [`encode_tlv_stream`].
+/// This is exported for use by other exported macros, do not use directly.
+#[doc(hidden)]
+#[macro_export]
+macro_rules! _encode_tlv_stream {
        ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}) => { {
+               $crate::_encode_tlv_stream!($stream, { $(($type, $field, $fieldty)),* }, &[])
+       } };
+       ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),* $(,)*}, $extra_tlvs: expr) => { {
                #[allow(unused_imports)]
                use $crate::{
                        ln::msgs::DecodeError,
@@ -117,6 +157,10 @@ macro_rules! encode_tlv_stream {
                $(
                        $crate::_encode_tlv!($stream, $type, $field, $fieldty);
                )*
+               for tlv in $extra_tlvs {
+                       let (typ, value): &(u64, Vec<u8>) = tlv;
+                       $crate::_encode_tlv!($stream, *typ, *value, required_vec);
+               }
 
                #[allow(unused_mut, unused_variables, unused_assignments)]
                #[cfg(debug_assertions)]
@@ -125,8 +169,12 @@ macro_rules! encode_tlv_stream {
                        $(
                                $crate::_check_encoded_tlv_order!(last_seen, $type, $fieldty);
                        )*
+                       for tlv in $extra_tlvs {
+                               let (typ, _): &(u64, Vec<u8>) = tlv;
+                               $crate::_check_encoded_tlv_order!(last_seen, *typ, required_vec);
+                       }
                }
-       } }
+       } };
 }
 
 /// Adds the length of the serialized field to a [`LengthCalculatingWriter`].
@@ -147,7 +195,7 @@ macro_rules! _get_varint_length_prefixed_tlv_length {
                BigSize(field_len as u64).write(&mut $len).expect("No in-memory data may fail to serialize");
                $len.0 += field_len;
        };
-       ($len: expr, $type: expr, $field: expr, vec_type) => {
+       ($len: expr, $type: expr, $field: expr, required_vec) => {
                $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $crate::util::ser::WithoutLength(&$field), required);
        };
        ($len: expr, $optional_type: expr, $optional_field: expr, option) => {
@@ -158,9 +206,23 @@ macro_rules! _get_varint_length_prefixed_tlv_length {
                        $len.0 += field_len;
                }
        };
-       ($len: expr, $type: expr, $field: expr, ignorable) => {
+       ($len: expr, $type: expr, $field: expr, optional_vec) => {
+               if !$field.is_empty() {
+                       $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, required_vec);
+               }
+       };
+       ($len: expr, $type: expr, $field: expr, (option: $trait: ident $(, $read_arg: expr)?)) => {
+               $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, option);
+       };
+       ($len: expr, $type: expr, $field: expr, (option, encoding: ($fieldty: ty, $encoding: ident))) => {
+               $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field.map(|f| $encoding(f)), option);
+       };
+       ($len: expr, $type: expr, $field: expr, upgradable_required) => {
                $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, required);
        };
+       ($len: expr, $type: expr, $field: expr, upgradable_option) => {
+               $crate::_get_varint_length_prefixed_tlv_length!($len, $type, $field, option);
+       };
 }
 
 /// See the documentation of [`write_tlv_fields`].
@@ -169,18 +231,27 @@ macro_rules! _get_varint_length_prefixed_tlv_length {
 #[macro_export]
 macro_rules! _encode_varint_length_prefixed_tlv {
        ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),*}) => { {
+               $crate::_encode_varint_length_prefixed_tlv!($stream, {$(($type, $field, $fieldty)),*}, &[])
+       } };
+       ($stream: expr, {$(($type: expr, $field: expr, $fieldty: tt)),*}, $extra_tlvs: expr) => { {
+               extern crate alloc;
                use $crate::util::ser::BigSize;
+               use alloc::vec::Vec;
                let len = {
                        #[allow(unused_mut)]
                        let mut len = $crate::util::ser::LengthCalculatingWriter(0);
                        $(
                                $crate::_get_varint_length_prefixed_tlv_length!(len, $type, $field, $fieldty);
                        )*
+                       for tlv in $extra_tlvs {
+                               let (typ, value): &(u64, Vec<u8>) = tlv;
+                               $crate::_get_varint_length_prefixed_tlv_length!(len, *typ, *value, required_vec);
+                       }
                        len.0
                };
                BigSize(len as u64).write($stream)?;
-               $crate::encode_tlv_stream!($stream, { $(($type, $field, $fieldty)),* });
-       } }
+               $crate::_encode_tlv_stream!($stream, { $(($type, $field, $fieldty)),* }, $extra_tlvs);
+       } };
 }
 
 /// Errors if there are missing required TLV types between the last seen type and the type currently being processed.
@@ -204,13 +275,22 @@ macro_rules! _check_decoded_tlv_order {
                        return Err(DecodeError::InvalidValue);
                }
        }};
+       ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
+               $crate::_check_decoded_tlv_order!($last_seen_type, $typ, $type, $field, required);
+       }};
        ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, option) => {{
                // no-op
        }};
-       ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, vec_type) => {{
+       ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, required_vec) => {{
+               $crate::_check_decoded_tlv_order!($last_seen_type, $typ, $type, $field, required);
+       }};
+       ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, optional_vec) => {{
                // no-op
        }};
-       ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, ignorable) => {{
+       ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, upgradable_required) => {{
+               _check_decoded_tlv_order!($last_seen_type, $typ, $type, $field, required)
+       }};
+       ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, upgradable_option) => {{
                // no-op
        }};
        ($last_seen_type: expr, $typ: expr, $type: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
@@ -243,13 +323,22 @@ macro_rules! _check_missing_tlv {
                        return Err(DecodeError::InvalidValue);
                }
        }};
-       ($last_seen_type: expr, $type: expr, $field: ident, vec_type) => {{
-               // no-op
+       ($last_seen_type: expr, $type: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
+               $crate::_check_missing_tlv!($last_seen_type, $type, $field, required);
+       }};
+       ($last_seen_type: expr, $type: expr, $field: ident, required_vec) => {{
+               $crate::_check_missing_tlv!($last_seen_type, $type, $field, required);
        }};
        ($last_seen_type: expr, $type: expr, $field: ident, option) => {{
                // no-op
        }};
-       ($last_seen_type: expr, $type: expr, $field: ident, ignorable) => {{
+       ($last_seen_type: expr, $type: expr, $field: ident, optional_vec) => {{
+               // no-op
+       }};
+       ($last_seen_type: expr, $type: expr, $field: ident, upgradable_required) => {{
+               _check_missing_tlv!($last_seen_type, $type, $field, required)
+       }};
+       ($last_seen_type: expr, $type: expr, $field: ident, upgradable_option) => {{
                // no-op
        }};
        ($last_seen_type: expr, $type: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
@@ -273,14 +362,34 @@ macro_rules! _decode_tlv {
        ($reader: expr, $field: ident, required) => {{
                $field = $crate::util::ser::Readable::read(&mut $reader)?;
        }};
-       ($reader: expr, $field: ident, vec_type) => {{
+       ($reader: expr, $field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {{
+               $field = $trait::read(&mut $reader $(, $read_arg)*)?;
+       }};
+       ($reader: expr, $field: ident, required_vec) => {{
                let f: $crate::util::ser::WithoutLength<Vec<_>> = $crate::util::ser::Readable::read(&mut $reader)?;
-               $field = Some(f.0);
+               $field = f.0;
        }};
        ($reader: expr, $field: ident, option) => {{
                $field = Some($crate::util::ser::Readable::read(&mut $reader)?);
        }};
-       ($reader: expr, $field: ident, ignorable) => {{
+       ($reader: expr, $field: ident, optional_vec) => {{
+               let f: $crate::util::ser::WithoutLength<Vec<_>> = $crate::util::ser::Readable::read(&mut $reader)?;
+               $field = Some(f.0);
+       }};
+       // `upgradable_required` indicates we're reading a required TLV that may have been upgraded
+       // without backwards compat. We'll error if the field is missing, and return `Ok(None)` if the
+       // field is present but we can no longer understand it.
+       // Note that this variant can only be used within a `MaybeReadable` read.
+       ($reader: expr, $field: ident, upgradable_required) => {{
+               $field = match $crate::util::ser::MaybeReadable::read(&mut $reader)? {
+                       Some(res) => res,
+                       _ => return Ok(None)
+               };
+       }};
+       // `upgradable_option` indicates we're reading an Option-al TLV that may have been upgraded
+       // without backwards compat. $field will be None if the TLV is missing or if the field is present
+       // but we can no longer understand it.
+       ($reader: expr, $field: ident, upgradable_option) => {{
                $field = $crate::util::ser::MaybeReadable::read(&mut $reader)?;
        }};
        ($reader: expr, $field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {{
@@ -494,7 +603,7 @@ macro_rules! impl_writeable_msg {
                impl $crate::util::ser::Writeable for $st {
                        fn write<W: $crate::util::ser::Writer>(&self, w: &mut W) -> Result<(), $crate::io::Error> {
                                $( self.$field.write(w)?; )*
-                               $crate::encode_tlv_stream!(w, {$(($type, self.$tlvfield, $fieldty)),*});
+                               $crate::encode_tlv_stream!(w, {$(($type, self.$tlvfield.as_ref(), $fieldty)),*});
                                Ok(())
                        }
                }
@@ -619,13 +728,22 @@ macro_rules! _init_tlv_based_struct_field {
        ($field: ident, option) => {
                $field
        };
-       ($field: ident, ignorable) => {
-               if $field.is_none() { return Ok(None); } else { $field.unwrap() }
+       ($field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {
+               $crate::_init_tlv_based_struct_field!($field, option)
+       };
+       ($field: ident, upgradable_required) => {
+               $field.0.unwrap()
+       };
+       ($field: ident, upgradable_option) => {
+               $field
        };
        ($field: ident, required) => {
                $field.0.unwrap()
        };
-       ($field: ident, vec_type) => {
+       ($field: ident, required_vec) => {
+               $field
+       };
+       ($field: ident, optional_vec) => {
                $field.unwrap()
        };
 }
@@ -637,31 +755,49 @@ macro_rules! _init_tlv_based_struct_field {
 #[macro_export]
 macro_rules! _init_tlv_field_var {
        ($field: ident, (default_value, $default: expr)) => {
-               let mut $field = $crate::util::ser::OptionDeserWrapper(None);
+               let mut $field = $crate::util::ser::RequiredWrapper(None);
        };
        ($field: ident, (static_value, $value: expr)) => {
                let $field;
        };
        ($field: ident, required) => {
-               let mut $field = $crate::util::ser::OptionDeserWrapper(None);
+               let mut $field = $crate::util::ser::RequiredWrapper(None);
        };
-       ($field: ident, vec_type) => {
-               let mut $field = Some(Vec::new());
+       ($field: ident, (required: $trait: ident $(, $read_arg: expr)?)) => {
+               $crate::_init_tlv_field_var!($field, required);
+       };
+       ($field: ident, required_vec) => {
+               let mut $field = Vec::new();
        };
        ($field: ident, option) => {
                let mut $field = None;
        };
-       ($field: ident, ignorable) => {
+       ($field: ident, optional_vec) => {
+               let mut $field = Some(Vec::new());
+       };
+       ($field: ident, (option, encoding: ($fieldty: ty, $encoding: ident))) => {
+               $crate::_init_tlv_field_var!($field, option);
+       };
+       ($field: ident, (option: $trait: ident $(, $read_arg: expr)?)) => {
+               $crate::_init_tlv_field_var!($field, option);
+       };
+       ($field: ident, upgradable_required) => {
+               let mut $field = $crate::util::ser::UpgradableRequired(None);
+       };
+       ($field: ident, upgradable_option) => {
                let mut $field = None;
        };
 }
 
 /// Equivalent to running [`_init_tlv_field_var`] then [`read_tlv_fields`].
 ///
+/// If any unused values are read, their type MUST be specified or else `rustc` will read them as an
+/// `i64`.
+///
 /// This is exported for use by other exported macros, do not use directly.
 #[doc(hidden)]
 #[macro_export]
-macro_rules! _init_and_read_tlv_fields {
+macro_rules! _init_and_read_len_prefixed_tlv_fields {
        ($reader: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
                $(
                        $crate::_init_tlv_field_var!($field, $fieldty);
@@ -673,11 +809,28 @@ macro_rules! _init_and_read_tlv_fields {
        }
 }
 
+/// Equivalent to running [`_init_tlv_field_var`] then [`decode_tlv_stream`].
+///
+/// If any unused values are read, their type MUST be specified or else `rustc` will read them as an
+/// `i64`.
+macro_rules! _init_and_read_tlv_stream {
+       ($reader: ident, {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}) => {
+               $(
+                       $crate::_init_tlv_field_var!($field, $fieldty);
+               )*
+
+               $crate::decode_tlv_stream!($reader, {
+                       $(($type, $field, $fieldty)),*
+               });
+       }
+}
+
 /// Implements [`Readable`]/[`Writeable`] for a struct storing it as a set of TLVs
 /// If `$fieldty` is `required`, then `$field` is a required field that is not an [`Option`] nor a [`Vec`].
 /// If `$fieldty` is `(default_value, $default)`, then `$field` will be set to `$default` if not present.
 /// If `$fieldty` is `option`, then `$field` is optional field.
-/// If `$fieldty` is `vec_type`, then `$field` is a [`Vec`], which needs to have its individual elements serialized.
+/// If `$fieldty` is `optional_vec`, then `$field` is a [`Vec`], which needs to have its individual elements serialized.
+///    Note that for `optional_vec` no bytes are written if the vec is empty
 ///
 /// For example,
 /// ```
@@ -693,7 +846,7 @@ macro_rules! _init_and_read_tlv_fields {
 ///    (0, tlv_integer, required),
 ///    (1, tlv_default_integer, (default_value, 7)),
 ///    (2, tlv_optional_integer, option),
-///    (3, tlv_vec_type_integer, vec_type),
+///    (3, tlv_vec_type_integer, optional_vec),
 /// });
 /// ```
 ///
@@ -729,7 +882,7 @@ macro_rules! impl_writeable_tlv_based {
 
                impl $crate::util::ser::Readable for $st {
                        fn read<R: $crate::io::Read>(reader: &mut R) -> Result<Self, $crate::ln::msgs::DecodeError> {
-                               $crate::_init_and_read_tlv_fields!(reader, {
+                               $crate::_init_and_read_len_prefixed_tlv_fields!(reader, {
                                        $(($type, $field, $fieldty)),*
                                });
                                Ok(Self {
@@ -764,7 +917,7 @@ macro_rules! tlv_stream {
 
                #[cfg_attr(test, derive(PartialEq))]
                #[derive(Debug)]
-               pub(super) struct $nameref<'a> {
+               pub(crate) struct $nameref<'a> {
                        $(
                                pub(super) $field: Option<tlv_record_ref_type!($fieldty)>,
                        )*
@@ -818,6 +971,8 @@ macro_rules! tlv_record_ref_type {
        ($type:ty) => { &'a $type };
 }
 
+#[doc(hidden)]
+#[macro_export]
 macro_rules! _impl_writeable_tlv_based_enum_common {
        ($st: ident, $(($variant_id: expr, $variant_name: ident) =>
                {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
@@ -829,7 +984,7 @@ macro_rules! _impl_writeable_tlv_based_enum_common {
                                        $($st::$variant_name { $(ref $field),* } => {
                                                let id: u8 = $variant_id;
                                                id.write(writer)?;
-                                               write_tlv_fields!(writer, {
+                                               $crate::write_tlv_fields!(writer, {
                                                        $(($type, *$field, $fieldty)),*
                                                });
                                        }),*
@@ -851,7 +1006,7 @@ macro_rules! _impl_writeable_tlv_based_enum_common {
 /// ```ignore
 /// impl_writeable_tlv_based_enum!(EnumName,
 ///   (0, StructVariantA) => {(0, required_variant_field, required), (1, optional_variant_field, option)},
-///   (1, StructVariantB) => {(0, variant_field_a, required), (1, variant_field_b, required), (2, variant_vec_field, vec_type)};
+///   (1, StructVariantB) => {(0, variant_field_a, required), (1, variant_field_b, required), (2, variant_vec_field, optional_vec)};
 ///   (2, TupleVariantA), (3, TupleVariantB),
 /// );
 /// ```
@@ -867,7 +1022,7 @@ macro_rules! impl_writeable_tlv_based_enum {
                {$(($type: expr, $field: ident, $fieldty: tt)),* $(,)*}
        ),* $(,)*;
        $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*) => {
-               _impl_writeable_tlv_based_enum_common!($st,
+               $crate::_impl_writeable_tlv_based_enum_common!($st,
                        $(($variant_id, $variant_name) => {$(($type, $field, $fieldty)),*}),*;
                        $(($tuple_variant_id, $tuple_variant_name)),*);
 
@@ -878,20 +1033,20 @@ macro_rules! impl_writeable_tlv_based_enum {
                                        $($variant_id => {
                                                // Because read_tlv_fields creates a labeled loop, we cannot call it twice
                                                // in the same function body. Instead, we define a closure and call it.
-                                               let f = || {
-                                                       _init_and_read_tlv_fields!(reader, {
+                                               let mut f = || {
+                                                       $crate::_init_and_read_len_prefixed_tlv_fields!(reader, {
                                                                $(($type, $field, $fieldty)),*
                                                        });
                                                        Ok($st::$variant_name {
                                                                $(
-                                                                       $field: _init_tlv_based_struct_field!($field, $fieldty)
+                                                                       $field: $crate::_init_tlv_based_struct_field!($field, $fieldty)
                                                                ),*
                                                        })
                                                };
                                                f()
                                        }),*
                                        $($tuple_variant_id => {
-                                               Ok($st::$tuple_variant_name(Readable::read(reader)?))
+                                               Ok($st::$tuple_variant_name($crate::util::ser::Readable::read(reader)?))
                                        }),*
                                        _ => {
                                                Err($crate::ln::msgs::DecodeError::UnknownRequiredFeature)
@@ -921,7 +1076,7 @@ macro_rules! impl_writeable_tlv_based_enum_upgradable {
        ),* $(,)*
        $(;
        $(($tuple_variant_id: expr, $tuple_variant_name: ident)),*  $(,)*)*) => {
-               _impl_writeable_tlv_based_enum_common!($st,
+               $crate::_impl_writeable_tlv_based_enum_common!($st,
                        $(($variant_id, $variant_name) => {$(($type, $field, $fieldty)),*}),*;
                        $($(($tuple_variant_id, $tuple_variant_name)),*)*);
 
@@ -932,13 +1087,13 @@ macro_rules! impl_writeable_tlv_based_enum_upgradable {
                                        $($variant_id => {
                                                // Because read_tlv_fields creates a labeled loop, we cannot call it twice
                                                // in the same function body. Instead, we define a closure and call it.
-                                               let f = || {
-                                                       _init_and_read_tlv_fields!(reader, {
+                                               let mut f = || {
+                                                       $crate::_init_and_read_len_prefixed_tlv_fields!(reader, {
                                                                $(($type, $field, $fieldty)),*
                                                        });
                                                        Ok(Some($st::$variant_name {
                                                                $(
-                                                                       $field: _init_tlv_based_struct_field!($field, $fieldty)
+                                                                       $field: $crate::_init_tlv_based_struct_field!($field, $fieldty)
                                                                ),*
                                                        }))
                                                };
@@ -948,7 +1103,7 @@ macro_rules! impl_writeable_tlv_based_enum_upgradable {
                                                Ok(Some($st::$tuple_variant_name(Readable::read(reader)?)))
                                        }),*)*
                                        _ if id % 2 == 1 => Ok(None),
-                                       _ => Err(DecodeError::UnknownRequiredFeature),
+                                       _ => Err($crate::ln::msgs::DecodeError::UnknownRequiredFeature),
                                }
                        }
                }
@@ -957,10 +1112,13 @@ macro_rules! impl_writeable_tlv_based_enum_upgradable {
 
 #[cfg(test)]
 mod tests {
-       use crate::io::{self, Cursor};
+       #[allow(unused_imports)]
        use crate::prelude::*;
+
+       use crate::io::{self, Cursor};
        use crate::ln::msgs::DecodeError;
        use crate::util::ser::{Writeable, HighZeroBytesDroppedBigSize, VecWriter};
+       use bitcoin::hashes::hex::FromHex;
        use bitcoin::secp256k1::PublicKey;
 
        // The BOLT TLV test cases don't include any tests which use our "required-value" logic since
@@ -978,7 +1136,7 @@ mod tests {
        #[test]
        fn tlv_v_short_read() {
                // We only expect a u32 for type 3 (which we are given), but the L says its 8 bytes.
-               if let Err(DecodeError::ShortRead) = tlv_reader(&::hex::decode(
+               if let Err(DecodeError::ShortRead) = tlv_reader(&<Vec<u8>>::from_hex(
                                concat!("0100", "0208deadbeef1badbeef", "0308deadbeef")
                                ).unwrap()[..]) {
                } else { panic!(); }
@@ -986,12 +1144,12 @@ mod tests {
 
        #[test]
        fn tlv_types_out_of_order() {
-               if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
+               if let Err(DecodeError::InvalidValue) = tlv_reader(&<Vec<u8>>::from_hex(
                                concat!("0100", "0304deadbeef", "0208deadbeef1badbeef")
                                ).unwrap()[..]) {
                } else { panic!(); }
                // ...even if its some field we don't understand
-               if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
+               if let Err(DecodeError::InvalidValue) = tlv_reader(&<Vec<u8>>::from_hex(
                                concat!("0208deadbeef1badbeef", "0100", "0304deadbeef")
                                ).unwrap()[..]) {
                } else { panic!(); }
@@ -1000,17 +1158,17 @@ mod tests {
        #[test]
        fn tlv_req_type_missing_or_extra() {
                // It's also bad if they included even fields we don't understand
-               if let Err(DecodeError::UnknownRequiredFeature) = tlv_reader(&::hex::decode(
+               if let Err(DecodeError::UnknownRequiredFeature) = tlv_reader(&<Vec<u8>>::from_hex(
                                concat!("0100", "0208deadbeef1badbeef", "0304deadbeef", "0600")
                                ).unwrap()[..]) {
                } else { panic!(); }
                // ... or if they're missing fields we need
-               if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
+               if let Err(DecodeError::InvalidValue) = tlv_reader(&<Vec<u8>>::from_hex(
                                concat!("0100", "0208deadbeef1badbeef")
                                ).unwrap()[..]) {
                } else { panic!(); }
                // ... even if that field is even
-               if let Err(DecodeError::InvalidValue) = tlv_reader(&::hex::decode(
+               if let Err(DecodeError::InvalidValue) = tlv_reader(&<Vec<u8>>::from_hex(
                                concat!("0304deadbeef", "0500")
                                ).unwrap()[..]) {
                } else { panic!(); }
@@ -1018,16 +1176,57 @@ mod tests {
 
        #[test]
        fn tlv_simple_good_cases() {
-               assert_eq!(tlv_reader(&::hex::decode(
+               assert_eq!(tlv_reader(&<Vec<u8>>::from_hex(
                                concat!("0208deadbeef1badbeef", "03041bad1dea")
                                ).unwrap()[..]).unwrap(),
                        (0xdeadbeef1badbeef, 0x1bad1dea, None));
-               assert_eq!(tlv_reader(&::hex::decode(
+               assert_eq!(tlv_reader(&<Vec<u8>>::from_hex(
                                concat!("0208deadbeef1badbeef", "03041bad1dea", "040401020304")
                                ).unwrap()[..]).unwrap(),
                        (0xdeadbeef1badbeef, 0x1bad1dea, Some(0x01020304)));
        }
 
+       #[derive(Debug, PartialEq)]
+       struct TestUpgradable {
+               a: u32,
+               b: u32,
+               c: Option<u32>,
+       }
+
+       fn upgradable_tlv_reader(s: &[u8]) -> Result<Option<TestUpgradable>, DecodeError> {
+               let mut s = Cursor::new(s);
+               let mut a = 0;
+               let mut b = 0;
+               let mut c: Option<u32> = None;
+               decode_tlv_stream!(&mut s, {(2, a, upgradable_required), (3, b, upgradable_required), (4, c, upgradable_option)});
+               Ok(Some(TestUpgradable { a, b, c, }))
+       }
+
+       #[test]
+       fn upgradable_tlv_simple_good_cases() {
+               assert_eq!(upgradable_tlv_reader(&<Vec<u8>>::from_hex(
+                       concat!("0204deadbeef", "03041bad1dea", "0404deadbeef")
+               ).unwrap()[..]).unwrap(),
+               Some(TestUpgradable { a: 0xdeadbeef, b: 0x1bad1dea, c: Some(0xdeadbeef) }));
+
+               assert_eq!(upgradable_tlv_reader(&<Vec<u8>>::from_hex(
+                       concat!("0204deadbeef", "03041bad1dea")
+               ).unwrap()[..]).unwrap(),
+               Some(TestUpgradable { a: 0xdeadbeef, b: 0x1bad1dea, c: None}));
+       }
+
+       #[test]
+       fn missing_required_upgradable() {
+               if let Err(DecodeError::InvalidValue) = upgradable_tlv_reader(&<Vec<u8>>::from_hex(
+                       concat!("0100", "0204deadbeef")
+                       ).unwrap()[..]) {
+               } else { panic!(); }
+               if let Err(DecodeError::InvalidValue) = upgradable_tlv_reader(&<Vec<u8>>::from_hex(
+                       concat!("0100", "03041bad1dea")
+               ).unwrap()[..]) {
+               } else { panic!(); }
+       }
+
        // BOLT TLV test cases
        fn tlv_reader_n1(s: &[u8]) -> Result<(Option<HighZeroBytesDroppedBigSize<u64>>, Option<u64>, Option<(PublicKey, u64, u64)>, Option<u16>), DecodeError> {
                let mut s = Cursor::new(s);
@@ -1043,7 +1242,7 @@ mod tests {
        fn bolt_tlv_bogus_stream() {
                macro_rules! do_test {
                        ($stream: expr, $reason: ident) => {
-                               if let Err(DecodeError::$reason) = tlv_reader_n1(&::hex::decode($stream).unwrap()[..]) {
+                               if let Err(DecodeError::$reason) = tlv_reader_n1(&<Vec<u8>>::from_hex($stream).unwrap()[..]) {
                                } else { panic!(); }
                        }
                }
@@ -1068,7 +1267,7 @@ mod tests {
        fn bolt_tlv_bogus_n1_stream() {
                macro_rules! do_test {
                        ($stream: expr, $reason: ident) => {
-                               if let Err(DecodeError::$reason) = tlv_reader_n1(&::hex::decode($stream).unwrap()[..]) {
+                               if let Err(DecodeError::$reason) = tlv_reader_n1(&<Vec<u8>>::from_hex($stream).unwrap()[..]) {
                                } else { panic!(); }
                        }
                }
@@ -1108,7 +1307,7 @@ mod tests {
        fn bolt_tlv_valid_n1_stream() {
                macro_rules! do_test {
                        ($stream: expr, $tlv1: expr, $tlv2: expr, $tlv3: expr, $tlv4: expr) => {
-                               if let Ok((tlv1, tlv2, tlv3, tlv4)) = tlv_reader_n1(&::hex::decode($stream).unwrap()[..]) {
+                               if let Ok((tlv1, tlv2, tlv3, tlv4)) = tlv_reader_n1(&<Vec<u8>>::from_hex($stream).unwrap()[..]) {
                                        assert_eq!(tlv1.map(|v| v.0), $tlv1);
                                        assert_eq!(tlv2, $tlv2);
                                        assert_eq!(tlv3, $tlv3);
@@ -1137,7 +1336,7 @@ mod tests {
                do_test!(concat!("02", "08", "0000000000000226"), None, Some((0 << 30) | (0 << 5) | (550 << 0)), None, None);
                do_test!(concat!("03", "31", "023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb00000000000000010000000000000002"),
                        None, None, Some((
-                               PublicKey::from_slice(&::hex::decode("023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb").unwrap()[..]).unwrap(), 1, 2)),
+                               PublicKey::from_slice(&<Vec<u8>>::from_hex("023da092f6980e58d2c037173180e9a465476026ee50f96695963e8efe436f54eb").unwrap()[..]).unwrap(), 1, 2)),
                        None);
                do_test!(concat!("fd00fe", "02", "0226"), None, None, None, Some(550));
        }
@@ -1147,27 +1346,27 @@ mod tests {
 
                stream.0.clear();
                _encode_varint_length_prefixed_tlv!(&mut stream, {(1, 1u8, required), (42, None::<u64>, option)});
-               assert_eq!(stream.0, ::hex::decode("03010101").unwrap());
+               assert_eq!(stream.0, <Vec<u8>>::from_hex("03010101").unwrap());
 
                stream.0.clear();
                _encode_varint_length_prefixed_tlv!(&mut stream, {(1, Some(1u8), option)});
-               assert_eq!(stream.0, ::hex::decode("03010101").unwrap());
+               assert_eq!(stream.0, <Vec<u8>>::from_hex("03010101").unwrap());
 
                stream.0.clear();
                _encode_varint_length_prefixed_tlv!(&mut stream, {(4, 0xabcdu16, required), (42, None::<u64>, option)});
-               assert_eq!(stream.0, ::hex::decode("040402abcd").unwrap());
+               assert_eq!(stream.0, <Vec<u8>>::from_hex("040402abcd").unwrap());
 
                stream.0.clear();
                _encode_varint_length_prefixed_tlv!(&mut stream, {(42, None::<u64>, option), (0xff, 0xabcdu16, required)});
-               assert_eq!(stream.0, ::hex::decode("06fd00ff02abcd").unwrap());
+               assert_eq!(stream.0, <Vec<u8>>::from_hex("06fd00ff02abcd").unwrap());
 
                stream.0.clear();
                _encode_varint_length_prefixed_tlv!(&mut stream, {(0, 1u64, required), (42, None::<u64>, option), (0xff, HighZeroBytesDroppedBigSize(0u64), required)});
-               assert_eq!(stream.0, ::hex::decode("0e00080000000000000001fd00ff00").unwrap());
+               assert_eq!(stream.0, <Vec<u8>>::from_hex("0e00080000000000000001fd00ff00").unwrap());
 
                stream.0.clear();
                _encode_varint_length_prefixed_tlv!(&mut stream, {(0, Some(1u64), option), (0xff, HighZeroBytesDroppedBigSize(0u64), required)});
-               assert_eq!(stream.0, ::hex::decode("0e00080000000000000001fd00ff00").unwrap());
+               assert_eq!(stream.0, <Vec<u8>>::from_hex("0e00080000000000000001fd00ff00").unwrap());
 
                Ok(())
        }