[fix lint warnings: NFTs pallet] fix clippy::missing_errors_doc lint …

…warnings (#14648)

* fix missing errors doc warnings

* cargo +nightly fmt

* Update frame/nfts/src/features/create_delete_item.rs

* Update frame/nfts/src/features/create_delete_item.rs

* Update frame/nfts/src/features/transfer.rs

* Update frame/nfts/src/features/create_delete_collection.rs

* add intra doc linking for errors

* fmt

* Apply suggestions from code review

Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

---------

Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

frame/nfts/src/common_functions.rs

@@ -31,7 +31,12 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 		Collection::<T, I>::get(collection).map(|i| i.owner)
 	}
 
-	/// Validate the `data` was signed by `signer` and the `signature` is correct.
+	/// Validates the signature of the given data with the provided signer's account ID.
+	///
+	/// # Errors
+	///
+	/// This function returns a [`WrongSignature`](crate::Error::WrongSignature) error if the
+	/// signature is invalid or the verification process fails.
 	pub fn validate_signature(
 		data: &Vec<u8>,
 		signature: &T::OffchainSignature,

frame/nfts/src/features/attributes.rs

@@ -381,21 +381,36 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 		Ok(result)
 	}
 
-	/// A helper method to construct attribute's key.
+	/// A helper method to construct an attribute's key.
+	///
+	/// # Errors
+	///
+	/// This function returns an [`IncorrectData`](crate::Error::IncorrectData) error if the
+	/// provided attribute `key` is too long.
 	pub fn construct_attribute_key(
 		key: Vec<u8>,
 	) -> Result<BoundedVec<u8, T::KeyLimit>, DispatchError> {
 		Ok(BoundedVec::try_from(key).map_err(|_| Error::<T, I>::IncorrectData)?)
 	}
 
-	/// A helper method to construct attribute's value.
+	/// A helper method to construct an attribute's value.
+	///
+	/// # Errors
+	///
+	/// This function returns an [`IncorrectData`](crate::Error::IncorrectData) error if the
+	/// provided `value` is too long.
 	pub fn construct_attribute_value(
 		value: Vec<u8>,
 	) -> Result<BoundedVec<u8, T::ValueLimit>, DispatchError> {
 		Ok(BoundedVec::try_from(value).map_err(|_| Error::<T, I>::IncorrectData)?)
 	}
 
 	/// A helper method to check whether a system attribute is set for a given item.
+	///
+	/// # Errors
+	///
+	/// This function returns an [`IncorrectData`](crate::Error::IncorrectData) error if the
+	/// provided pallet attribute is too long.
 	pub fn has_system_attribute(
 		collection: &T::CollectionId,
 		item: &T::ItemId,

frame/nfts/src/features/create_delete_collection.rs

@@ -19,6 +19,17 @@ use crate::*;
 use frame_support::pallet_prelude::*;
 
 impl<T: Config<I>, I: 'static> Pallet<T, I> {
+	/// Create a new collection with the given `collection`, `owner`, `admin`, `config`, `deposit`,
+	/// and `event`.
+	///
+	/// This function creates a new collection with the provided parameters. It reserves the
+	/// required deposit from the owner's account, sets the collection details, assigns admin roles,
+	/// and inserts the provided configuration. Finally, it emits the specified event upon success.
+	///
+	/// # Errors
+	///
+	/// This function returns a [`CollectionIdInUse`](crate::Error::CollectionIdInUse) error if the
+	/// collection ID is already in use.
 	pub fn do_create_collection(
 		collection: T::CollectionId,
 		owner: T::AccountId,
@@ -56,6 +67,27 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 		Ok(())
 	}
 
+	/// Destroy the specified collection with the given `collection`, `witness`, and
+	/// `maybe_check_owner`.
+	///
+	/// This function destroys the specified collection if it exists and meets the necessary
+	/// conditions. It checks the provided `witness` against the actual collection details and
+	/// removes the collection along with its associated metadata, attributes, and configurations.
+	/// The necessary deposits are returned to the corresponding accounts, and the roles and
+	/// configurations for the collection are cleared. Finally, it emits the `Destroyed` event upon
+	/// successful destruction.
+	///
+	/// # Errors
+	///
+	/// This function returns a dispatch error in the following cases:
+	/// - If the collection ID is not found
+	///   ([`UnknownCollection`](crate::Error::UnknownCollection)).
+	/// - If the provided `maybe_check_owner` does not match the actual owner
+	///   ([`NoPermission`](crate::Error::NoPermission)).
+	/// - If the collection is not empty (contains items)
+	///   ([`CollectionNotEmpty`](crate::Error::CollectionNotEmpty)).
+	/// - If the `witness` does not match the actual collection details
+	///   ([`BadWitness`](crate::Error::BadWitness)).
 	pub fn do_destroy_collection(
 		collection: T::CollectionId,
 		witness: DestroyWitness,

frame/nfts/src/features/create_delete_item.rs

@@ -19,6 +19,25 @@ use crate::*;
 use frame_support::{pallet_prelude::*, traits::ExistenceRequirement};
 
 impl<T: Config<I>, I: 'static> Pallet<T, I> {
+	/// Mint a new unique item with the given `collection`, `item`, and other minting configuration
+	/// details.
+	///
+	/// This function performs the minting of a new unique item. It checks if the item does not
+	/// already exist in the given collection, and if the max supply limit (if configured) is not
+	/// reached. It also reserves the required deposit for the item and sets the item details
+	/// accordingly.
+	///
+	/// # Errors
+	///
+	/// This function returns a dispatch error in the following cases:
+	/// - If the collection ID is invalid ([`UnknownCollection`](crate::Error::UnknownCollection)).
+	/// - If the item already exists in the collection
+	///   ([`AlreadyExists`](crate::Error::AlreadyExists)).
+	/// - If the item configuration already exists
+	///   ([`InconsistentItemConfig`](crate::Error::InconsistentItemConfig)).
+	/// - If the max supply limit (if configured) for the collection is reached
+	///   ([`MaxSupplyReached`](crate::Error::MaxSupplyReached)).
+	/// - If any error occurs in the `with_details_and_config` closure.
 	pub fn do_mint(
 		collection: T::CollectionId,
 		item: T::ItemId,
@@ -163,6 +182,13 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 		Ok(())
 	}
 
+	/// Burns the specified item with the given `collection`, `item`, and `with_details`.
+	///
+	/// # Errors
+	///
+	/// This function returns a dispatch error in the following cases:
+	/// - If the collection ID is invalid ([`UnknownCollection`](crate::Error::UnknownCollection)).
+	/// - If the item is locked ([`ItemLocked`](crate::Error::ItemLocked)).
 	pub fn do_burn(
 		collection: T::CollectionId,
 		item: T::ItemId,

frame/nfts/src/features/metadata.rs

@@ -209,6 +209,11 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 	}
 
 	/// A helper method to construct metadata.
+	///
+	/// # Errors
+	///
+	/// This function returns an [`IncorrectMetadata`](crate::Error::IncorrectMetadata) dispatch
+	/// error if the provided metadata is too long.
 	pub fn construct_metadata(
 		metadata: Vec<u8>,
 	) -> Result<BoundedVec<u8, T::StringLimit>, DispatchError> {

frame/nfts/src/features/transfer.rs

@@ -19,6 +19,17 @@ use crate::*;
 use frame_support::pallet_prelude::*;
 
 impl<T: Config<I>, I: 'static> Pallet<T, I> {
+	/// Performs the transfer action for the given `collection`, `item`, `dest`, and `event`.
+	///
+	/// # Errors
+	///
+	/// This function returns a dispatch error in the following cases:
+	/// - If the collection ID is invalid ([`UnknownCollection`](crate::Error::UnknownCollection)).
+	/// - If the item ID is invalid ([`UnknownItem`](crate::Error::UnknownItem)).
+	/// - If the item is locked or transferring it is disabled
+	///   ([`ItemLocked`](crate::Error::ItemLocked)).
+	/// - If the collection or item is non-transferable
+	///   ([`ItemsNonTransferable`](crate::Error::ItemsNonTransferable)).
 	pub fn do_transfer(
 		collection: T::CollectionId,
 		item: T::ItemId,