Migrate custom error trait impls to thiserror (#1856)

* Migrate to thiserror

* missing bits

* review comment

* Apply suggestions from code review

Co-authored-by: Niklas Adolfsson <niklasadolfsson1@gmail.com>

* From<scale_decode::visitor::Error> to remove Into::intos

* scale crates for core::error::Error

* bump msrv 1.81

* make signer crate compile

---------

Co-authored-by: Niklas Adolfsson <niklasadolfsson1@gmail.com>
Co-authored-by: James Wilson <james.wilson@parity.io>

Cargo.toml

@@ -35,7 +35,7 @@ resolver = "2"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2021"
 version = "0.38.0"
-rust-version = "1.74.0"
+rust-version = "1.81.0"
 license = "Apache-2.0 OR GPL-3.0"
 repository = "https://github.com/paritytech/subxt"
 documentation = "https://docs.rs/subxt"
@@ -94,16 +94,16 @@ proc-macro2 = "1.0.86"
 quote = "1.0.37"
 regex = { version = "1.11.0", default-features = false }
 scale-info = { version = "2.11.4", default-features = false }
-scale-value = { version = "0.17.0", default-features = false }
+scale-value = { version = "0.18.0", default-features = false }
-scale-bits = { version = "0.6.0", default-features = false }
+scale-bits = { version = "0.7.0", default-features = false }
-scale-decode = { version = "0.14.0", default-features = false }
+scale-decode = { version = "0.16.0", default-features = false }
-scale-encode = { version = "0.8.0", default-features = false }
+scale-encode = { version = "0.10.0", default-features = false }
-scale-typegen = "0.9.0"
+scale-typegen = "0.10.0"
-scale-typegen-description = "0.9.0"
+scale-typegen-description = "0.10.0"
 serde = { version = "1.0.210", default-features = false, features = ["derive"] }
 serde_json = { version = "1.0.128", default-features = false }
 syn = { version = "2.0.77", features = ["full", "extra-traits"] }
-thiserror = "1.0.64"
+thiserror = { version = "2.0.0", default-features = false }
 tokio = { version = "1.40", default-features = false }
 tracing = { version = "0.1.40", default-features = false }
 tracing-wasm = "0.2.1"

core/Cargo.toml

@@ -19,10 +19,6 @@ default = ["std"]
 std = [
     "codec/std",
     "scale-info/std",
-    "scale-value/std",
-    "scale-bits/std",
-    "scale-decode/std",
-    "scale-encode/std",
     "frame-metadata/std",
     "subxt-metadata/std",
     "hex/std",
@@ -49,6 +45,8 @@ hex = { workspace = true, default-features = false, features = ["alloc"] }
 serde = { workspace = true, default-features = false, features = ["derive"] }
 serde_json = { workspace = true, default-features = false, features = ["raw_value", "alloc"] }
 hashbrown = { workspace = true }
+thiserror = { workspace = true, default-features = false }
+
 
 # For ss58 encoding AccountId32 to serialize them properly:
 base58 = { workspace = true }
@@ -82,4 +80,4 @@ rustdoc-args = ["--cfg", "docsrs"]
 default-features = true
 
 [lints]
-workspace = true
+workspace = true

core/src/error.rs

@@ -4,61 +4,56 @@
 
 //! The errors that can be emitted in this crate.
 
-use core::fmt::Display;
-
 use alloc::boxed::Box;
 use alloc::string::String;
 use subxt_metadata::StorageHasher;
+use thiserror::Error as DeriveError;
 
 /// The error emitted when something goes wrong.
-#[derive(Debug)]
+#[derive(Debug, DeriveError)]
 pub enum Error {
     /// Codec error.
+    #[error("Codec error: {0}")]
     Codec(codec::Error),
     /// Metadata error.
-    Metadata(MetadataError),
+    #[error(transparent)]
+    Metadata(#[from] MetadataError),
     /// Storage address error.
-    StorageAddress(StorageAddressError),
+    #[error(transparent)]
+    StorageAddress(#[from] StorageAddressError),
     /// Error decoding to a [`crate::dynamic::Value`].
-    Decode(scale_decode::Error),
+    #[error("Error decoding into dynamic value: {0}")]
+    Decode(#[from] scale_decode::Error),
     /// Error encoding from a [`crate::dynamic::Value`].
-    Encode(scale_encode::Error),
+    #[error("Error encoding from dynamic value: {0}")]
+    Encode(#[from] scale_encode::Error),
     /// Error constructing the appropriate extrinsic params.
-    ExtrinsicParams(ExtrinsicParamsError),
+    #[error(transparent)]
+    ExtrinsicParams(#[from] ExtrinsicParamsError),
     /// Block body error.
-    Block(BlockError),
+    #[error("Error working with block_body: {0}")]
+    Block(#[from] BlockError),
 }
 
-impl core::fmt::Display for Error {
+impl From<scale_decode::visitor::DecodeError> for Error {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+    fn from(err: scale_decode::visitor::DecodeError) -> Error {
-        match self {
+        Error::Decode(err.into())
-            Error::Codec(e) => write!(f, "Scale codec error: {e}"),
-            Error::Metadata(e) => write!(f, "Metadata Error: {e}"),
-            Error::StorageAddress(e) => write!(f, "Storage Error: {e}"),
-            Error::Decode(e) => write!(f, "Error decoding into dynamic value: {e}"),
-            Error::Encode(e) => write!(f, "Error encoding from dynamic value: {e}"),
-            Error::ExtrinsicParams(e) => write!(f, "Extrinsic params error: {e}"),
-            Error::Block(e) => write!(f, "Error working with block_body: {}", e),
-        }
     }
 }
 
-#[cfg(feature = "std")]
+// TODO: when `codec::Error` implements `core::Error`
-impl std::error::Error for Error {}
+// remove this impl and replace it by thiserror #[from]
-
+impl From<codec::Error> for Error {
-impl_from!(ExtrinsicParamsError => Error::ExtrinsicParams);
+    fn from(err: codec::Error) -> Error {
-impl_from!(BlockError => Error::Block);
+        Error::Codec(err)
-impl_from!(MetadataError => Error::Metadata);
+    }
-impl_from!(scale_decode::Error => Error::Decode);
+}
-impl_from!(scale_decode::visitor::DecodeError => Error::Decode);
-impl_from!(scale_encode::Error => Error::Encode);
-impl_from!(StorageAddressError => Error::StorageAddress);
-impl_from!(codec::Error => Error::Codec);
 
 /// Block error
-#[derive(Debug)]
+#[derive(Debug, DeriveError)]
 pub enum BlockError {
     /// Leftover bytes found after decoding the extrinsic.
+    #[error("After decoding the extrinsic at index {extrinsic_index}, {num_leftover_bytes} bytes were left, suggesting that decoding may have failed")]
     LeftoverBytes {
         /// Index of the extrinsic that failed to decode.
         extrinsic_index: usize,
@@ -66,6 +61,7 @@ pub enum BlockError {
         num_leftover_bytes: usize,
     },
     /// Something went wrong decoding the extrinsic.
+    #[error("Failed to decode extrinsic at index {extrinsic_index}: {error}")]
     ExtrinsicDecodeError {
         /// Index of the extrinsic that failed to decode.
         extrinsic_index: usize,
@@ -73,121 +69,74 @@ pub enum BlockError {
         error: ExtrinsicDecodeError,
     },
 }
-impl Display for BlockError {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        match self {
-            BlockError::LeftoverBytes {
-                extrinsic_index,
-                num_leftover_bytes,
-            } => {
-                write!(
-                    f,
-                    "After decoding the extrinsic at index {extrinsic_index}, {num_leftover_bytes} bytes were left, suggesting that decoding may have failed"
-                )
-            }
-            BlockError::ExtrinsicDecodeError {
-                extrinsic_index,
-                error,
-            } => {
-                write!(
-                    f,
-                    "Failed to decode extrinsic at index {extrinsic_index}: {error}"
-                )
-            }
-        }
-    }
-}
 
 /// An alias for [`frame_decode::extrinsics::ExtrinsicDecodeError`].
 ///
 pub type ExtrinsicDecodeError = frame_decode::extrinsics::ExtrinsicDecodeError;
 
 /// Something went wrong trying to access details in the metadata.
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, DeriveError)]
 #[non_exhaustive]
 pub enum MetadataError {
     /// The DispatchError type isn't available in the metadata
+    #[error("The DispatchError type isn't available")]
     DispatchErrorNotFound,
     /// Type not found in metadata.
+    #[error("Type with ID {0} not found")]
     TypeNotFound(u32),
     /// Pallet not found (index).
+    #[error("Pallet with index {0} not found")]
     PalletIndexNotFound(u8),
     /// Pallet not found (name).
+    #[error("Pallet with name {0} not found")]
     PalletNameNotFound(String),
     /// Variant not found.
+    #[error("Variant with index {0} not found")]
     VariantIndexNotFound(u8),
     /// Constant not found.
+    #[error("Constant with name {0} not found")]
     ConstantNameNotFound(String),
     /// Call not found.
+    #[error("Call with name {0} not found")]
     CallNameNotFound(String),
     /// Runtime trait not found.
+    #[error("Runtime trait with name {0} not found")]
     RuntimeTraitNotFound(String),
     /// Runtime method not found.
+    #[error("Runtime method with name {0} not found")]
     RuntimeMethodNotFound(String),
     /// Call type not found in metadata.
+    #[error("Call type not found in pallet with index {0}")]
     CallTypeNotFoundInPallet(u8),
     /// Event type not found in metadata.
+    #[error("Event type not found in pallet with index {0}")]
     EventTypeNotFoundInPallet(u8),
     /// Storage details not found in metadata.
+    #[error("Storage details not found in pallet with name {0}")]
     StorageNotFoundInPallet(String),
     /// Storage entry not found.
+    #[error("Storage entry {0} not found")]
     StorageEntryNotFound(String),
     /// The generated interface used is not compatible with the node.
+    #[error("The generated code is not compatible with the node")]
     IncompatibleCodegen,
     /// Custom value not found.
+    #[error("Custom value with name {0} not found")]
     CustomValueNameNotFound(String),
 }
-impl Display for MetadataError {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        match self {
-            MetadataError::DispatchErrorNotFound => {
-                write!(f, "The DispatchError type isn't available")
-            }
-            MetadataError::TypeNotFound(e) => write!(f, "Type with ID {e} not found"),
-            MetadataError::PalletIndexNotFound(e) => write!(f, "Pallet with index {e} not found"),
-            MetadataError::PalletNameNotFound(e) => write!(f, "Pallet with name {e} not found"),
-            MetadataError::VariantIndexNotFound(e) => write!(f, "Variant with index {e} not found"),
-            MetadataError::ConstantNameNotFound(e) => write!(f, "Constant with name {e} not found"),
-            MetadataError::CallNameNotFound(e) => write!(f, "Call with name {e} not found"),
-            MetadataError::RuntimeTraitNotFound(e) => {
-                write!(f, "Runtime trait with name {e} not found")
-            }
-            MetadataError::RuntimeMethodNotFound(e) => {
-                write!(f, "Runtime method with name {e} not found")
-            }
-            MetadataError::CallTypeNotFoundInPallet(e) => {
-                write!(f, "Call type not found in pallet with index {e}")
-            }
-            MetadataError::EventTypeNotFoundInPallet(e) => {
-                write!(f, "Event type not found in pallet with index {e}")
-            }
-            MetadataError::StorageNotFoundInPallet(e) => {
-                write!(f, "Storage details not found in pallet with name {e}")
-            }
-            MetadataError::StorageEntryNotFound(e) => write!(f, "Storage entry {e} not found"),
-            MetadataError::IncompatibleCodegen => {
-                write!(f, "The generated code is not compatible with the node")
-            }
-            MetadataError::CustomValueNameNotFound(e) => {
-                write!(f, "Custom value with name {e} not found")
-            }
-        }
-    }
-}
-
-#[cfg(feature = "std")]
-impl std::error::Error for MetadataError {}
 
 /// Something went wrong trying to encode or decode a storage address.
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, DeriveError)]
 #[non_exhaustive]
 pub enum StorageAddressError {
     /// Storage lookup does not have the expected number of keys.
+    #[error("Storage lookup requires {expected} keys but more keys have been provided.")]
     TooManyKeys {
         /// The number of keys provided in the storage address.
         expected: usize,
     },
     /// This storage entry in the metadata does not have the correct number of hashers to fields.
+    #[error("Storage entry in metadata does not have the correct number of hashers to fields")]
     WrongNumberOfHashers {
         /// The number of hashers in the metadata for this storage entry.
         hashers: usize,
@@ -195,12 +144,16 @@ pub enum StorageAddressError {
         fields: usize,
     },
     /// We weren't given enough bytes to decode the storage address/key.
+    #[error("Not enough remaining bytes to decode the storage address/key")]
     NotEnoughBytes,
     /// We have leftover bytes after decoding the storage address.
+    #[error("We have leftover bytes after decoding the storage address")]
     TooManyBytes,
     /// The bytes of a storage address are not the expected address for decoding the storage keys of the address.
+    #[error("Storage address bytes are not the expected format. Addresses need to be at least 16 bytes (pallet ++ entry) and follow a structure given by the hashers defined in the metadata")]
     UnexpectedAddressBytes,
     /// An invalid hasher was used to reconstruct a value from a chunk of bytes that is part of a storage address. Hashers where the hash does not contain the original value are invalid for this purpose.
+    #[error("An invalid hasher was used to reconstruct a value with type ID {ty_id} from a hash formed by a {hasher:?} hasher. This is only possible for concat-style hashers or the identity hasher")]
     HasherCannotReconstructKey {
         /// Type id of the key's type.
         ty_id: u32,
@@ -209,47 +162,14 @@ pub enum StorageAddressError {
     },
 }
 
-impl Display for StorageAddressError {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        match self {
-            StorageAddressError::TooManyKeys { expected } => write!(
-                f,
-                "Storage lookup requires {expected} keys but more keys have been provided."
-            ),
-            StorageAddressError::WrongNumberOfHashers { .. } => write!(
-                f,
-                "Storage entry in metadata does not have the correct number of hashers to fields"
-            ),
-            StorageAddressError::NotEnoughBytes => write!(
-                f,
-                "Not enough remaining bytes to decode the storage address/key"
-            ),
-            StorageAddressError::TooManyBytes => write!(
-                f,
-                "We have leftover bytes after decoding the storage address"
-            ),
-            StorageAddressError::UnexpectedAddressBytes => write!(
-                f,
-                "Storage address bytes are not the expected format. Addresses need to be at least 16 bytes (pallet ++ entry) and follow a structure given by the hashers defined in the metadata"
-            ),
-            StorageAddressError::HasherCannotReconstructKey { ty_id, hasher } => write!(
-                f,
-                "An invalid hasher was used to reconstruct a value with type ID {ty_id} from a hash formed by a {hasher:?} hasher. This is only possible for concat-style hashers or the identity hasher"
-            ),
-        }
-    }
-}
-
-#[cfg(feature = "std")]
-impl std::error::Error for StorageAddressError {}
-
 /// An error that can be emitted when trying to construct an instance of [`crate::config::ExtrinsicParams`],
 /// encode data from the instance, or match on signed extensions.
-#[derive(Debug)]
+#[derive(Debug, DeriveError)]
 #[non_exhaustive]
 pub enum ExtrinsicParamsError {
     /// Cannot find a type id in the metadata. The context provides some additional
     /// information about the source of the error (eg the signed extension name).
+    #[error("Cannot find type id '{type_id} in the metadata (context: {context})")]
     MissingTypeId {
         /// Type ID.
         type_id: u32,
@@ -257,29 +177,13 @@ pub enum ExtrinsicParamsError {
         context: &'static str,
     },
     /// A signed extension in use on some chain was not provided.
+    #[error("The chain expects a signed extension with the name {0}, but we did not provide one")]
     UnknownSignedExtension(String),
     /// Some custom error.
+    #[error("Error constructing extrinsic parameters: {0}")]
     Custom(Box<dyn CustomError>),
 }
 
-impl Display for ExtrinsicParamsError {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        match self {
-            ExtrinsicParamsError::MissingTypeId { type_id, context } => write!(
-                f,
-                "Cannot find type id '{type_id} in the metadata (context: {context})"
-            ),
-            ExtrinsicParamsError::UnknownSignedExtension(e) => write!(
-                f,
-                "The chain expects a signed extension with the name {e}, but we did not provide one"
-            ),
-            ExtrinsicParamsError::Custom(e) => {
-                write!(f, "Error constructing extrinsic parameters: {e}")
-            }
-        }
-    }
-}
-
 /// Anything implementing this trait can be used in [`ExtrinsicParamsError::Custom`].
 #[cfg(feature = "std")]
 pub trait CustomError: std::error::Error + Send + Sync + 'static {}
@@ -292,9 +196,6 @@ pub trait CustomError: core::fmt::Debug + core::fmt::Display + Send + Sync + 'st
 #[cfg(not(feature = "std"))]
 impl<T: core::fmt::Debug + core::fmt::Display + Send + Sync + 'static> CustomError for T {}
 
-#[cfg(feature = "std")]
-impl std::error::Error for ExtrinsicParamsError {}
-
 impl From<core::convert::Infallible> for ExtrinsicParamsError {
     fn from(value: core::convert::Infallible) -> Self {
         match value {}

core/src/macros.rs

@@ -18,14 +18,4 @@ macro_rules! cfg_substrate_compat {
 	};
 }
 
-macro_rules! impl_from {
-    ($module_path:path => $delegate_ty:ident :: $variant:ident) => {
-        impl From<$module_path> for $delegate_ty {
-            fn from(val: $module_path) -> Self {
-                $delegate_ty::$variant(val.into())
-            }
-        }
-    };
-}
-
 pub(crate) use {cfg_feature, cfg_substrate_compat};

core/src/storage/storage_key.rs

@@ -265,6 +265,7 @@ impl StorageKey for Vec<scale_value::Value> {
                 Some(value_bytes) => {
                     let value =
                         scale_value::scale::decode_as_type(&mut &*value_bytes, ty_id, types)?;
+
                     result.push(value.remove_context());
                 }
                 None => {

core/src/utils/account_id.rs

@@ -6,14 +6,13 @@
 //! This doesn't contain much functionality itself, but is easy to convert to/from an `sp_core::AccountId32`
 //! for instance, to gain functionality without forcing a dependency on Substrate crates here.
 
-use core::fmt::Display;
-
 use alloc::format;
 use alloc::string::String;
 use alloc::vec;
 use alloc::vec::Vec;
 use codec::{Decode, Encode};
 use serde::{Deserialize, Serialize};
+use thiserror::Error as DeriveError;
 
 /// A 32-byte cryptographic identifier. This is a simplified version of Substrate's
 /// `sp_core::crypto::AccountId32`. To obtain more functionality, convert this into
@@ -106,29 +105,19 @@ impl AccountId32 {
 }
 
 /// An error obtained from trying to interpret an SS58 encoded string into an AccountId32
-#[derive(Clone, Copy, Eq, PartialEq, Debug)]
+#[derive(Clone, Copy, Eq, PartialEq, Debug, DeriveError)]
 #[allow(missing_docs)]
 pub enum FromSs58Error {
+    #[error("Base 58 requirement is violated")]
     BadBase58,
+    #[error("Length is bad")]
     BadLength,
+    #[error("Invalid checksum")]
     InvalidChecksum,
+    #[error("Invalid SS58 prefix byte.")]
     InvalidPrefix,
 }
 
-impl Display for FromSs58Error {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        match self {
-            FromSs58Error::BadBase58 => write!(f, "Base 58 requirement is violated"),
-            FromSs58Error::BadLength => write!(f, "Length is bad"),
-            FromSs58Error::InvalidChecksum => write!(f, "Invalid checksum"),
-            FromSs58Error::InvalidPrefix => write!(f, "Invalid SS58 prefix byte."),
-        }
-    }
-}
-
-#[cfg(feature = "std")]
-impl std::error::Error for FromSs58Error {}
-
 // We do this just to get a checksum to help verify the validity of the address in to_ss58check
 fn ss58hash(data: &[u8]) -> Vec<u8> {
     use blake2::{Blake2b512, Digest};

core/src/utils/account_id20.rs

@@ -4,13 +4,12 @@
 
 //! `AccountId20` is a representation of Ethereum address derived from hashing the public key.
 
-use core::fmt::Display;
-
 use alloc::format;
 use alloc::string::String;
 use codec::{Decode, Encode};
 use keccak_hash::keccak;
 use serde::{Deserialize, Serialize};
+use thiserror::Error as DeriveError;
 
 #[derive(
     Copy,
@@ -72,27 +71,17 @@ impl AccountId20 {
 }
 
 /// An error obtained from trying to interpret a hex encoded string into an AccountId20
-#[derive(Clone, Copy, Eq, PartialEq, Debug)]
+#[derive(Clone, Copy, Eq, PartialEq, Debug, DeriveError)]
 #[allow(missing_docs)]
 pub enum FromChecksumError {
+    #[error("Length is bad")]
     BadLength,
+    #[error("Invalid checksum")]
     InvalidChecksum,
+    #[error("Invalid checksum prefix byte.")]
     InvalidPrefix,
 }
 
-impl Display for FromChecksumError {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        match self {
-            FromChecksumError::BadLength => write!(f, "Length is bad"),
-            FromChecksumError::InvalidChecksum => write!(f, "Invalid checksum"),
-            FromChecksumError::InvalidPrefix => write!(f, "Invalid checksum prefix byte."),
-        }
-    }
-}
-
-#[cfg(feature = "std")]
-impl std::error::Error for FromChecksumError {}
-
 impl Serialize for AccountId20 {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where

metadata/Cargo.toml

@@ -24,6 +24,7 @@ frame-metadata = { workspace = true, default-features = false, features = ["curr
 codec = { package = "parity-scale-codec", workspace = true, default-features = false, features = ["derive"] }
 polkadot-sdk = { workspace = true, features = ["sp-crypto-hashing"] }
 hashbrown = { workspace = true }
+thiserror = { workspace = true, default-features = false }
 
 [dev-dependencies]
 bitvec = { workspace = true, features = ["alloc"] }

metadata/src/from_into/mod.rs

@@ -2,56 +2,33 @@
 // This file is dual-licensed as Apache-2.0 or GPL-3.0.
 // see LICENSE for license details.
 
-use core::fmt::Display;
-
 use alloc::string::String;
-
+use thiserror::Error as DeriveError;
 mod v14;
 mod v15;
 
 /// An error emitted if something goes wrong converting [`frame_metadata`]
 /// types into [`crate::Metadata`].
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq, Eq, DeriveError)]
 #[non_exhaustive]
 pub enum TryFromError {
     /// Type missing from type registry
+    #[error("Type id {0} is expected but not found in the type registry")]
     TypeNotFound(u32),
     /// Type was not a variant/enum type
+    #[error("Type {0} was not a variant/enum type, but is expected to be one")]
     VariantExpected(u32),
     /// An unsupported metadata version was provided.
+    #[error("Cannot convert v{0} metadata into Metadata type")]
     UnsupportedMetadataVersion(u32),
     /// Type name missing from type registry
+    #[error("Type name {0} is expected but not found in the type registry")]
     TypeNameNotFound(String),
     /// Invalid type path.
+    #[error("Type has an invalid path {0}")]
     InvalidTypePath(String),
 }
 
-impl Display for TryFromError {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        match self {
-            TryFromError::TypeNotFound(e) => write!(
-                f,
-                "Type id {e} is expected but not found in the type registry"
-            ),
-            TryFromError::VariantExpected(e) => write!(
-                f,
-                "Type {e} was not a variant/enum type, but is expected to be one"
-            ),
-            TryFromError::UnsupportedMetadataVersion(e) => {
-                write!(f, "Cannot convert v{e} metadata into Metadata type")
-            }
-            TryFromError::TypeNameNotFound(e) => write!(
-                f,
-                "Type name {e} is expected but not found in the type registry"
-            ),
-            TryFromError::InvalidTypePath(e) => write!(f, "Type has an invalid path {e}"),
-        }
-    }
-}
-
-#[cfg(feature = "std")]
-impl std::error::Error for TryFromError {}
-
 impl From<crate::Metadata> for frame_metadata::RuntimeMetadataPrefixed {
     fn from(value: crate::Metadata) -> Self {
         let m: frame_metadata::v15::RuntimeMetadataV15 = value.into();

signer/Cargo.toml

@@ -72,6 +72,7 @@ secp256k1 = { workspace = true, optional = true, features = [
     "recovery",
 ] }
 keccak-hash = { workspace = true, optional = true }
+thiserror = { workspace = true, default-features = false }
 
 # These are used if the polkadot-js-compat feature is enabled
 serde = { workspace = true, optional = true }

signer/src/crypto/secret_uri.rs

@@ -2,13 +2,13 @@
 // This file is dual-licensed as Apache-2.0 or GPL-3.0.
 // see LICENSE for license details.
 
-use core::fmt::Display;
-
 use super::DeriveJunction;
 use alloc::{string::ToString, vec::Vec};
 use regex::Regex;
 use secrecy::SecretString;
 
+use thiserror::Error as DeriveError;
+
 // This code is taken from sp_core::crypto::DeriveJunction. The logic should be identical,
 // though the code is tweaked a touch!
 
@@ -116,23 +116,13 @@ impl core::str::FromStr for SecretUri {
 }
 
 /// This is returned if `FromStr` cannot parse a string into a `SecretUri`.
-#[derive(Debug, Copy, Clone, PartialEq)]
+#[derive(Debug, Copy, Clone, PartialEq, DeriveError)]
 pub enum SecretUriError {
     /// Parsing the secret URI from a string failed; wrong format.
+    #[error("Invalid secret phrase format")]
     InvalidFormat,
 }
 
-impl Display for SecretUriError {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        match self {
-            SecretUriError::InvalidFormat => write!(f, "Invalid secret phrase format"),
-        }
-    }
-}
-
-#[cfg(feature = "std")]
-impl std::error::Error for SecretUriError {}
-
 once_static_cloned! {
     /// Interpret a phrase like:
     ///

signer/src/ecdsa.rs

@@ -7,11 +7,13 @@ use codec::Encode;
 use polkadot_sdk::sp_crypto_hashing;
 
 use crate::crypto::{seed_from_entropy, DeriveJunction, SecretUri};
-use core::{fmt::Display, str::FromStr};
+use core::str::FromStr;
 use hex::FromHex;
 use secp256k1::{ecdsa::RecoverableSignature, Message, Secp256k1, SecretKey};
 use secrecy::ExposeSecret;
 
+use thiserror::Error as DeriveError;
+
 const SECRET_KEY_LENGTH: usize = 32;
 
 /// Seed bytes used to generate a key pair.
@@ -222,33 +224,33 @@ pub(crate) mod internal {
 }
 
 /// An error handed back if creating a keypair fails.
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, DeriveError)]
 pub enum Error {
     /// Invalid seed.
+    #[error("Invalid seed (was it the wrong length?)")]
     InvalidSeed,
     /// Invalid seed.
+    #[error("Invalid seed for ECDSA, contained soft junction")]
     SoftJunction,
     /// Invalid phrase.
+    #[error("Cannot parse phrase: {0}")]
     Phrase(bip39::Error),
     /// Invalid hex.
+    #[error("Cannot parse hex string: {0}")]
     Hex(hex::FromHexError),
 }
-impl Display for Error {
+
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+impl From<hex::FromHexError> for Error {
-        match self {
+    fn from(err: hex::FromHexError) -> Self {
-            Error::InvalidSeed => write!(f, "Invalid seed (was it the wrong length?)"),
+        Error::Hex(err)
-            Error::SoftJunction => write!(f, "Invalid seed for ECDSA, contained soft junction"),
-            Error::Phrase(e) => write!(f, "Cannot parse phrase: {e}"),
-            Error::Hex(e) => write!(f, "Cannot parse hex string: {e}"),
-        }
     }
 }
 
-impl_from!(bip39::Error => Error::Phrase);
+impl From<bip39::Error> for Error {
-impl_from!(hex::FromHexError => Error::Hex);
+    fn from(err: bip39::Error) -> Self {
-
+        Error::Phrase(err)
-#[cfg(feature = "std")]
+    }
-impl std::error::Error for Error {}
+}
 
 /// Dev accounts, helpful for testing but not to be used in production,
 /// since the secret keys are known.

signer/src/eth.rs

@@ -6,11 +6,12 @@
 
 use crate::ecdsa;
 use alloc::format;
-use core::fmt::{Display, Formatter};
 use core::str::FromStr;
 use keccak_hash::keccak;
 use secp256k1::Message;
 
+use thiserror::Error as DeriveError;
+
 const SECRET_KEY_LENGTH: usize = 32;
 
 /// Bytes representing a private key.
@@ -201,29 +202,16 @@ pub fn verify<M: AsRef<[u8]>>(sig: &Signature, message: M, pubkey: &PublicKey) -
 }
 
 /// An error handed back if creating a keypair fails.
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, DeriveError)]
 pub enum Error {
     /// Invalid seed.
+    #[error("Invalid seed (was it the wrong length?)")]
     InvalidSeed,
     /// Invalid derivation path.
+    #[error("Could not derive from path; some values in the path may have been >= 2^31?")]
     DeriveFromPath,
 }
 
-impl Display for Error {
-    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
-        match self {
-            Error::InvalidSeed => write!(f, "Invalid seed (was it the wrong length?)"),
-            Error::DeriveFromPath => write!(
-                f,
-                "Could not derive from path; some values in the path may have been >= 2^31?"
-            ),
-        }
-    }
-}
-
-#[cfg(feature = "std")]
-impl std::error::Error for Error {}
-
 /// Dev accounts, helpful for testing but not to be used in production,
 /// since the secret keys are known.
 pub mod dev {

signer/src/polkadot_js_compat.rs

@@ -5,7 +5,6 @@
 //! A Polkadot-JS account loader.
 
 use base64::Engine;
-use core::fmt::Display;
 use crypto_secretbox::{
     aead::{Aead, KeyInit},
     Key, Nonce, XSalsa20Poly1305,
@@ -13,6 +12,8 @@ use crypto_secretbox::{
 use serde::Deserialize;
 use subxt_core::utils::AccountId32;
 
+use thiserror::Error as DeriveError;
+
 use crate::sr25519;
 
 /// Given a JSON keypair as exported from Polkadot-JS, this returns an [`sr25519::Keypair`]
@@ -22,15 +23,19 @@ pub fn decrypt_json(json: &str, password: &str) -> Result<sr25519::Keypair, Erro
 }
 
 /// Error
-#[derive(Debug)]
+#[derive(Debug, DeriveError)]
 pub enum Error {
     /// Error decoding JSON.
-    Json(serde_json::Error),
+    #[error("Invalid JSON: {0}")]
+    Json(#[from] serde_json::Error),
     /// The keypair has an unsupported encoding.
+    #[error("Unsupported encoding.")]
     UnsupportedEncoding,
     /// Base64 decoding error.
-    Base64(base64::DecodeError),
+    #[error("Base64 decoding error: {0}")]
+    Base64(#[from] base64::DecodeError),
     /// Wrong Scrypt parameters
+    #[error("Unsupported Scrypt parameters: N: {n}, p: {p}, r: {r}")]
     UnsupportedScryptParameters {
         /// N
         n: u32,
@@ -40,37 +45,16 @@ pub enum Error {
         r: u32,
     },
     /// Decryption error.
-    Secretbox(crypto_secretbox::Error),
+    #[error("Decryption error: {0}")]
+    Secretbox(#[from] crypto_secretbox::Error),
     /// sr25519 keypair error.
-    Sr25519(sr25519::Error),
+    #[error(transparent)]
+    Sr25519(#[from] sr25519::Error),
     /// The decrypted keys are not valid.
+    #[error("The decrypted keys are not valid.")]
     InvalidKeys,
 }
 
-impl_from!(serde_json::Error => Error::Json);
-impl_from!(base64::DecodeError => Error::Base64);
-impl_from!(crypto_secretbox::Error => Error::Secretbox);
-impl_from!(sr25519::Error => Error::Sr25519);
-
-impl Display for Error {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        match self {
-            Error::Json(e) => write!(f, "Invalid JSON: {e}"),
-            Error::UnsupportedEncoding => write!(f, "Unsupported encoding."),
-            Error::Base64(e) => write!(f, "Base64 decoding error: {e}"),
-            Error::UnsupportedScryptParameters { n, p, r } => {
-                write!(f, "Unsupported Scrypt parameters: N: {n}, p: {p}, r: {r}")
-            }
-            Error::Secretbox(e) => write!(f, "Decryption error: {e}"),
-            Error::Sr25519(e) => write!(f, "{e}"),
-            Error::InvalidKeys => write!(f, "The decrypted keys are not valid."),
-        }
-    }
-}
-
-#[cfg(feature = "std")]
-impl std::error::Error for Error {}
-
 #[derive(Deserialize)]
 struct EncryptionMetadata {
     /// Descriptor for the content

signer/src/sr25519.rs

@@ -4,7 +4,7 @@
 
 //! An sr25519 keypair implementation.
 
-use core::{fmt::Display, str::FromStr};
+use core::str::FromStr;
 
 use crate::crypto::{seed_from_entropy, DeriveJunction, SecretUri};
 
@@ -15,6 +15,8 @@ use schnorrkel::{
 };
 use secrecy::ExposeSecret;
 
+use thiserror::Error as DeriveError;
+
 const SECRET_KEY_LENGTH: usize = schnorrkel::keys::MINI_SECRET_KEY_LENGTH;
 const SIGNING_CTX: &[u8] = b"substrate";
 
@@ -203,35 +205,39 @@ pub fn verify<M: AsRef<[u8]>>(sig: &Signature, message: M, pubkey: &PublicKey) -
 }
 
 /// An error handed back if creating a keypair fails.
-#[derive(Debug)]
+#[derive(Debug, DeriveError)]
 pub enum Error {
     /// Invalid seed.
+    #[error("Invalid seed (was it the wrong length?)")]
     InvalidSeed,
     /// Invalid phrase.
+    #[error("Cannot parse phrase: {0}")]
     Phrase(bip39::Error),
     /// Invalid hex.
+    #[error("Cannot parse hex string: {0}")]
     Hex(hex::FromHexError),
     /// Signature error.
+    #[error("Signature error: {0}")]
     Signature(schnorrkel::SignatureError),
 }
 
-impl_from!(bip39::Error => Error::Phrase);
+impl From<schnorrkel::SignatureError> for Error {
-impl_from!(hex::FromHexError => Error::Hex);
+    fn from(value: schnorrkel::SignatureError) -> Self {
-impl_from!(schnorrkel::SignatureError => Error::Signature);
+        Error::Signature(value)
-
-impl Display for Error {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        match self {
-            Error::InvalidSeed => write!(f, "Invalid seed (was it the wrong length?)"),
-            Error::Phrase(e) => write!(f, "Cannot parse phrase: {e}"),
-            Error::Hex(e) => write!(f, "Cannot parse hex string: {e}"),
-            Error::Signature(e) => write!(f, "Signature error: {e}"),
-        }
     }
 }
 
-#[cfg(feature = "std")]
+impl From<hex::FromHexError> for Error {
-impl std::error::Error for Error {}
+    fn from(err: hex::FromHexError) -> Self {
+        Error::Hex(err)
+    }
+}
+
+impl From<bip39::Error> for Error {
+    fn from(err: bip39::Error) -> Self {
+        Error::Phrase(err)
+    }
+}
 
 /// Dev accounts, helpful for testing but not to be used in production,
 /// since the secret keys are known.

signer/src/utils.rs

@@ -35,13 +35,3 @@ macro_rules! once_static_cloned {
         )+
     };
 }
-
-macro_rules! impl_from {
-    ($module_path:path => $delegate_ty:ident :: $variant:ident) => {
-        impl From<$module_path> for $delegate_ty {
-            fn from(val: $module_path) -> Self {
-                $delegate_ty::$variant(val.into())
-            }
-        }
-    };
-}