Deprecation info support in RuntimeMetadataIR (paritytech#4851)

### Description: 
* Adds `DeprecationStatusIR` enum to sp_metadata_ir.
Deprecation info for simple items.
* Adds `DeprecationInfoIR` enum to sp_metadata_ir.
It is a deprecation info for an enums/errors/calls. Contains
`DeprecationStatusIR`.
Denotes full/partial deprecation of the type or its variants/calls
* Adds `deprecation_info` field to 
       - `RuntimeApiMetadataIR`
       - `RuntimeApiMethodMetadataIR`
       - `StorageEntryMetadataIR`
       - `PalletConstantMetadataIR`
       - `PalletCallMetadataIR`
       - `PalletMetadataIR`
       - `PalletEventMetadataIR`
       - `PalletErrorMetadataIR`

### Testing done: 
- Unit tests to check whether or not correct `note`/`since` texts are
getting propagated to the metadata structs.
- UI test to check for error message in case of incorrect attribute
usage.
There's also some test updates to make sure that deprecation attributes
are getting propagated to the relevant structs.

see: paritytech#4098, Solution: A

### Examples of produced deprecation info metadata
They can be found in:
 - Tests for `frame-support`
 - hackmd link https://hackmd.io/@Zett98/Bys0YgbcR

---------

Co-authored-by: GitHub Action <[email protected]>
Co-authored-by: command-bot <>
Co-authored-by: Bastian Köcher <[email protected]>

prdoc/pr_4851.prdoc

@@ -0,0 +1,40 @@
+# Schema: Polkadot SDK PRDoc Schema (prdoc) v1.0.0
+# See doc at https://raw.githubusercontent.com/paritytech/polkadot-sdk/master/prdoc/schema_user.json
+
+title: Add support for deprecation metadata in `RuntimeMetadataIr` entries.
+
+doc:
+  - audience: 
+      - Runtime dev
+      - Runtime user
+    description: |
+      Changes introduced are listed below.
+      Adds `DeprecationStatusIR` enum to sp_metadata_ir.
+        - Is a deprecation info for simple items.
+      Adds `DeprecationInfoIR` enum to sp_metadata_ir.
+        - It is a deprecation info for an enums/errors/calls. Contains `DeprecationStatusIR`.
+          Also denotes full/partial deprecation of the type or its variants/calls.
+      Adds `deprecation_info` field to 
+        - `RuntimeApiMetadataIR`
+        - `RuntimeApiMethodMetadataIR`
+        - `StorageEntryMetadataIR`
+        - `PalletConstantMetadataIR`
+        - `PalletCallMetadataIR`
+        - `PalletMetadataIR`
+        - `PalletEventMetadataIR`
+        - `PalletErrorMetadataIR`
+      Examples of the deprecation info produced can be seen inside
+        - Tests for `frame-support`
+        - hackmd link https://hackmd.io/@Zett98/Bys0YgbcR
+
+crates:
+  - name: frame-support-procedural
+    bump: patch
+  - name: frame-support
+    bump: major
+  - name: sp-api-proc-macro
+    bump: patch
+  - name: sp-api
+    bump: patch
+  - name: sp-metadata-ir
+    bump: major

substrate/frame/support/procedural/examples/proc_main/inject_runtime_type.rs

@@ -43,6 +43,7 @@ fn derive_impl_works_with_no_aggregated_types() {
 		type Block = super::Block;
 		type AccountId = super::AccountId;
 		type PalletInfo = super::PalletInfo;
+		type ExampleConstant = ();
 	}
 
 	assert_type_eq_all!(<DummyRuntime as Config>::RuntimeOrigin, ());

substrate/frame/support/procedural/examples/proc_main/runtime.rs

@@ -14,6 +14,7 @@
 // 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.
+#![allow(deprecated, clippy::deprecated_semver)]
 
 use super::{frame_system, Block};
 use crate::derive_impl;
@@ -121,6 +122,7 @@ mod runtime {
 	// Ensure that the runtime does not export the calls from the pallet
 	#[runtime::pallet_index(4)]
 	#[runtime::disable_call]
+	#[deprecated = "example"]
 	pub type PalletWithDisabledCall = pallet_with_disabled_call::Pallet<Runtime>;
 
 	// Ensure that the runtime does not export the unsigned calls from the pallet

substrate/frame/support/procedural/src/construct_runtime/expand/metadata.rs

@@ -46,7 +46,7 @@ pub fn expand_runtime_metadata(
 			let index = &decl.index;
 			let storage = expand_pallet_metadata_storage(&filtered_names, runtime, decl);
 			let calls = expand_pallet_metadata_calls(&filtered_names, runtime, decl);
-			let event = expand_pallet_metadata_events(&filtered_names, runtime, scrate, decl);
+			let event = expand_pallet_metadata_events(&filtered_names, runtime, decl);
 			let constants = expand_pallet_metadata_constants(runtime, decl);
 			let errors = expand_pallet_metadata_errors(runtime, decl);
 			let docs = expand_pallet_metadata_docs(runtime, decl);
@@ -58,7 +58,7 @@ pub fn expand_runtime_metadata(
 					#attr
 				}
 			});
-
+			let deprecation_info = expand_pallet_metadata_deprecation(runtime, decl);
 			quote! {
 				#attr
 				#scrate::__private::metadata_ir::PalletMetadataIR {
@@ -70,6 +70,7 @@ pub fn expand_runtime_metadata(
 					constants: #constants,
 					error: #errors,
 					docs: #docs,
+					deprecation_info: #deprecation_info,
 				}
 			}
 		})
@@ -200,7 +201,6 @@ fn expand_pallet_metadata_calls(
 fn expand_pallet_metadata_events(
 	filtered_names: &[&'static str],
 	runtime: &Ident,
-	scrate: &TokenStream,
 	decl: &Pallet,
 ) -> TokenStream {
 	if filtered_names.contains(&"Event") {
@@ -220,16 +220,21 @@ fn expand_pallet_metadata_events(
 
 		quote! {
 			Some(
-				#scrate::__private::metadata_ir::PalletEventMetadataIR {
-					ty: #scrate::__private::scale_info::meta_type::<#pallet_event>()
-				}
+				#pallet_event::event_metadata::<#pallet_event>()
 			)
 		}
 	} else {
 		quote!(None)
 	}
 }
 
+fn expand_pallet_metadata_deprecation(runtime: &Ident, decl: &Pallet) -> TokenStream {
+	let path = &decl.path;
+	let instance = decl.instance.as_ref().into_iter();
+
+	quote! { #path::Pallet::<#runtime #(, #path::#instance)*>::deprecation_info() }
+}
+
 fn expand_pallet_metadata_constants(runtime: &Ident, decl: &Pallet) -> TokenStream {
 	let path = &decl.path;
 	let instance = decl.instance.as_ref().into_iter();

substrate/frame/support/procedural/src/construct_runtime/parse.rs

@@ -130,9 +130,9 @@ impl Parse for WhereSection {
 			definitions.push(definition);
 			if !input.peek(Token![,]) {
 				if !input.peek(token::Brace) {
-					return Err(input.error("Expected `,` or `{`"))
+					return Err(input.error("Expected `,` or `{`"));
 				}
-				break
+				break;
 			}
 			input.parse::<Token![,]>()?;
 		}
@@ -144,7 +144,7 @@ impl Parse for WhereSection {
 				"`{:?}` was declared above. Please use exactly one declaration for `{:?}`.",
 				kind, kind
 			);
-			return Err(Error::new(*kind_span, msg))
+			return Err(Error::new(*kind_span, msg));
 		}
 		Ok(Self { span: input.span() })
 	}
@@ -173,7 +173,7 @@ impl Parse for WhereDefinition {
 		} else if lookahead.peek(keyword::UncheckedExtrinsic) {
 			(input.parse::<keyword::UncheckedExtrinsic>()?.span(), WhereKind::UncheckedExtrinsic)
 		} else {
-			return Err(lookahead.error())
+			return Err(lookahead.error());
 		};
 
 		let _: Token![=] = input.parse()?;
@@ -270,7 +270,7 @@ impl Parse for PalletDeclaration {
 		{
 			return Err(input.error(
 				"Unexpected tokens, expected one of `::{`, `exclude_parts`, `use_parts`, `=`, `,`",
-			))
+			));
 		} else {
 			is_expanded.then_some(extra_parts)
 		};
@@ -283,7 +283,7 @@ impl Parse for PalletDeclaration {
 			let _: keyword::use_parts = input.parse()?;
 			SpecifiedParts::Use(parse_pallet_parts_no_generic(input)?)
 		} else if !input.peek(Token![=]) && !input.peek(Token![,]) && !input.is_empty() {
-			return Err(input.error("Unexpected tokens, expected one of `exclude_parts`, `=`, `,`"))
+			return Err(input.error("Unexpected tokens, expected one of `exclude_parts`, `=`, `,`"));
 		} else {
 			SpecifiedParts::All
 		};
@@ -295,7 +295,7 @@ impl Parse for PalletDeclaration {
 			let index = index.base10_parse::<u8>()?;
 			Some(index)
 		} else if !input.peek(Token![,]) && !input.is_empty() {
-			return Err(input.error("Unexpected tokens, expected one of `=`, `,`"))
+			return Err(input.error("Unexpected tokens, expected one of `=`, `,`"));
 		} else {
 			None
 		};
@@ -339,7 +339,7 @@ impl Parse for PalletPath {
 			let ident = input.call(Ident::parse_any)?;
 			res.inner.segments.push(ident.into());
 		} else {
-			return Err(lookahead.error())
+			return Err(lookahead.error());
 		}
 
 		while input.peek(Token![::]) && input.peek3(Ident) {
@@ -370,7 +370,7 @@ fn parse_pallet_parts(input: ParseStream) -> Result<Vec<PalletPart>> {
 				"`{}` was already declared before. Please remove the duplicate declaration",
 				part.name(),
 			);
-			return Err(Error::new(part.keyword.span(), msg))
+			return Err(Error::new(part.keyword.span(), msg));
 		}
 	}
 
@@ -505,7 +505,7 @@ impl Parse for PalletPart {
 				keyword.name(),
 				valid_generics,
 			);
-			return Err(syn::Error::new(keyword.span(), msg))
+			return Err(syn::Error::new(keyword.span(), msg));
 		}
 
 		Ok(Self { keyword, generics })
@@ -566,7 +566,7 @@ fn parse_pallet_parts_no_generic(input: ParseStream) -> Result<Vec<PalletPartNoG
 				"`{}` was already declared before. Please remove the duplicate declaration",
 				part.keyword.name(),
 			);
-			return Err(Error::new(part.keyword.span(), msg))
+			return Err(Error::new(part.keyword.span(), msg));
 		}
 	}
 
@@ -592,6 +592,8 @@ pub struct Pallet {
 	pub cfg_pattern: Vec<cfg_expr::Expression>,
 	/// The doc literals
 	pub docs: Vec<syn::Expr>,
+	/// attributes
+	pub attrs: Vec<syn::Attribute>,
 }
 
 impl Pallet {
@@ -650,7 +652,7 @@ enum PalletsConversion {
 /// incrementally from last explicit or 0.
 fn convert_pallets(pallets: Vec<PalletDeclaration>) -> syn::Result<PalletsConversion> {
 	if pallets.iter().any(|pallet| pallet.pallet_parts.is_none()) {
-		return Ok(PalletsConversion::Implicit(pallets))
+		return Ok(PalletsConversion::Implicit(pallets));
 	}
 
 	let mut indices = HashMap::new();
@@ -678,15 +680,15 @@ fn convert_pallets(pallets: Vec<PalletDeclaration>) -> syn::Result<PalletsConver
 				);
 				let mut err = syn::Error::new(used_pallet.span(), &msg);
 				err.combine(syn::Error::new(pallet.name.span(), msg));
-				return Err(err)
+				return Err(err);
 			}
 
 			if let Some(used_pallet) = names.insert(pallet.name.clone(), pallet.name.span()) {
 				let msg = "Two pallets with the same name!";
 
 				let mut err = syn::Error::new(used_pallet, &msg);
 				err.combine(syn::Error::new(pallet.name.span(), &msg));
-				return Err(err)
+				return Err(err);
 			}
 
 			let mut pallet_parts = pallet.pallet_parts.expect("Checked above");
@@ -712,7 +714,7 @@ fn convert_pallets(pallets: Vec<PalletDeclaration>) -> syn::Result<PalletsConver
 									}
 								})
 							);
-							return Err(syn::Error::new(part.keyword.span(), msg))
+							return Err(syn::Error::new(part.keyword.span(), msg));
 						}
 					},
 				SpecifiedParts::All => (),
@@ -738,7 +740,7 @@ fn convert_pallets(pallets: Vec<PalletDeclaration>) -> syn::Result<PalletsConver
 					if attr.path().segments.first().map_or(false, |s| s.ident != "cfg") {
 						let msg = "Unsupported attribute, only #[cfg] is supported on pallet \
 						declarations in `construct_runtime`";
-						return Err(syn::Error::new(attr.span(), msg))
+						return Err(syn::Error::new(attr.span(), msg));
 					}
 
 					attr.parse_args_with(|input: syn::parse::ParseStream| {
@@ -762,6 +764,7 @@ fn convert_pallets(pallets: Vec<PalletDeclaration>) -> syn::Result<PalletsConver
 				cfg_pattern,
 				pallet_parts,
 				docs: vec![],
+				attrs: pallet.attrs.clone(),
 			})
 		})
 		.collect::<Result<Vec<_>>>()?;