Implement #[pallet::composite_enum] (#13722)

* Implement #[pallet::hold_reason] * Appease clippy * cargo fmt * Update test expectations * Update test expectations * Support composite_enum attribute instead * Update test expectations * Change hold_reason to composite_enum * Add UI test for unsupported identifier when using composite_enum * Fix comment * Add documentation for pallet::composable_enum * More docs * cargo fmt
2026-06-22 01:01:03 +00:00 · 2023-04-04 20:28:46 +08:00
parent c268f3d3c8
commit 1a55f961c6
26 changed files with 682 additions and 11 deletions
@@ -0,0 +1,139 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use quote::ToTokens;
+use syn::spanned::Spanned;
+
+pub mod keyword {
+	use super::*;
+
+	syn::custom_keyword!(FreezeReason);
+	syn::custom_keyword!(HoldReason);
+	syn::custom_keyword!(LockId);
+	syn::custom_keyword!(SlashReason);
+	pub enum CompositeKeyword {
+		FreezeReason(FreezeReason),
+		HoldReason(HoldReason),
+		LockId(LockId),
+		SlashReason(SlashReason),
+	}
+
+	impl Spanned for CompositeKeyword {
+		fn span(&self) -> proc_macro2::Span {
+			use CompositeKeyword::*;
+			match self {
+				FreezeReason(inner) => inner.span(),
+				HoldReason(inner) => inner.span(),
+				LockId(inner) => inner.span(),
+				SlashReason(inner) => inner.span(),
+			}
+		}
+	}
+
+	impl syn::parse::Parse for CompositeKeyword {
+		fn parse(input: syn::parse::ParseStream) -> syn::Result<Self> {
+			let lookahead = input.lookahead1();
+			if lookahead.peek(FreezeReason) {
+				Ok(Self::FreezeReason(input.parse()?))
+			} else if lookahead.peek(HoldReason) {
+				Ok(Self::HoldReason(input.parse()?))
+			} else if lookahead.peek(LockId) {
+				Ok(Self::LockId(input.parse()?))
+			} else if lookahead.peek(SlashReason) {
+				Ok(Self::SlashReason(input.parse()?))
+			} else {
+				Err(lookahead.error())
+			}
+		}
+	}
+
+	impl std::fmt::Display for CompositeKeyword {
+		fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+			use CompositeKeyword::*;
+			write!(
+				f,
+				"{}",
+				match self {
+					FreezeReason(_) => "FreezeReason",
+					HoldReason(_) => "HoldReason",
+					LockId(_) => "LockId",
+					SlashReason(_) => "SlashReason",
+				}
+			)
+		}
+	}
+}
+
+pub struct CompositeDef {
+	/// The index of the HoldReason item in the pallet module.
+	pub index: usize,
+	/// The composite keyword used (contains span).
+	pub composite_keyword: keyword::CompositeKeyword,
+	/// The span of the pallet::composite_enum attribute.
+	pub attr_span: proc_macro2::Span,
+}
+
+impl CompositeDef {
+	pub fn try_from(
+		attr_span: proc_macro2::Span,
+		index: usize,
+		scrate: &proc_macro2::Ident,
+		item: &mut syn::Item,
+	) -> syn::Result<Self> {
+		let item = if let syn::Item::Enum(item) = item {
+			item
+		} else {
+			return Err(syn::Error::new(
+				item.span(),
+				"Invalid pallet::composite_enum, expected enum item",
+			))
+		};
+
+		if !matches!(item.vis, syn::Visibility::Public(_)) {
+			let msg = format!("Invalid pallet::composite_enum, `{}` must be public", item.ident);
+			return Err(syn::Error::new(item.span(), msg))
+		}
+
+		let has_derive_attr = item.attrs.iter().any(|attr| {
+			attr.parse_meta()
+				.ok()
+				.map(|meta| match meta {
+					syn::Meta::List(syn::MetaList { path, .. }) =>
+						path.get_ident().map(|ident| ident == "derive").unwrap_or(false),
+					_ => false,
+				})
+				.unwrap_or(false)
+		});
+
+		if !has_derive_attr {
+			let derive_attr: syn::Attribute = syn::parse_quote! {
+				#[derive(
+					Copy, Clone, Eq, PartialEq, Ord, PartialOrd,
+					#scrate::codec::Encode, #scrate::codec::Decode, #scrate::codec::MaxEncodedLen,
+					#scrate::scale_info::TypeInfo,
+					#scrate::RuntimeDebug,
+				)]
+			};
+			item.attrs.push(derive_attr);
+		}
+
+		let composite_keyword =
+			syn::parse2::<keyword::CompositeKeyword>(item.ident.to_token_stream())?;
+
+		Ok(CompositeDef { index, composite_keyword, attr_span })
+	}
+}