Subxt Metadata: #[no_std] compatibility (#1401)

* no-std tests and porting of subxt-metadata

* update pipeline

* fix generate custom metadata test

* fix cargo run command

* adjust pipeline

* remove prelude from subxt-metadata

* revert autoformatting of Cargo.toml

* remove alloc::format! again, still causes linker errors

* add no-std-build for thumbv7em-none-eabi target

* remove std feature flag

* remove libc and add small readme with test instructions

* change ci for nightly no std

metadata/src/utils/ordered_map.rs

@@ -2,7 +2,9 @@
 // This file is dual-licensed as Apache-2.0 or GPL-3.0.
 // see LICENSE for license details.
 
-use std::collections::HashMap;
+use alloc::vec::Vec;
+use core::mem;
+use hashbrown::HashMap;
 
 /// A minimal ordered map to let one search for
 /// things by key or get the values in insert order.
@@ -23,7 +25,7 @@ impl<K, V> Default for OrderedMap<K, V> {
 
 impl<K, V> OrderedMap<K, V>
 where
-    K: PartialEq + Eq + std::hash::Hash,
+    K: PartialEq + Eq + core::hash::Hash,
 {
     /// Create a new, empty [`OrderedMap`].
     pub fn new() -> Self {
@@ -47,8 +49,8 @@ where
     where
         F: FnMut(&V) -> bool,
     {
-        let values = std::mem::take(&mut self.values);
-        let map = std::mem::take(&mut self.map);
+        let values = mem::take(&mut self.values);
+        let map = mem::take(&mut self.map);
 
         // Filter the values, storing a map from old to new positions:
         let mut new_values = Vec::new();
@@ -78,8 +80,8 @@ where
     /// Get an item by its key.
     pub fn get_by_key<Q>(&self, key: &Q) -> Option<&V>
     where
-        K: std::borrow::Borrow<Q>,
-        Q: std::hash::Hash + Eq + ?Sized,
+        K: alloc::borrow::Borrow<Q>,
+        Q: core::hash::Hash + Eq + ?Sized,
     {
         self.map.get(key).and_then(|&v| self.values.get(v))
     }
@@ -107,7 +109,7 @@ where
 
 impl<K, V> FromIterator<(K, V)> for OrderedMap<K, V>
 where
-    K: PartialEq + Eq + std::hash::Hash,
+    K: PartialEq + Eq + core::hash::Hash,
 {
     fn from_iter<T: IntoIterator<Item = (K, V)>>(iter: T) -> Self {
         let mut map = OrderedMap::new();

metadata/src/utils/retain.rs

@@ -8,8 +8,9 @@ use crate::{
     ExtrinsicMetadata, Metadata, OuterEnumsMetadata, PalletMetadataInner, RuntimeApiMetadataInner,
     StorageEntryType,
 };
+use alloc::collections::BTreeMap;
+use hashbrown::HashSet;
 use scale_info::TypeDef;
-use std::collections::{BTreeMap, HashSet};
 
 /// Collect all type IDs needed to represent the provided pallet.
 fn collect_pallet_types(pallet: &PalletMetadataInner, type_ids: &mut HashSet<u32>) {

metadata/src/utils/validation.rs

@@ -8,9 +8,10 @@ use crate::{
     CustomMetadata, CustomValueMetadata, ExtrinsicMetadata, Metadata, PalletMetadata,
     RuntimeApiMetadata, RuntimeApiMethodMetadata, StorageEntryMetadata, StorageEntryType,
 };
+use alloc::vec::Vec;
+use hashbrown::HashMap;
 use outer_enum_hashes::OuterEnumHashes;
 use scale_info::{form::PortableForm, Field, PortableRegistry, TypeDef, TypeDefVariant, Variant};
-use std::collections::HashMap;
 
 pub mod outer_enum_hashes;
 

metadata/src/utils/validation/outer_enum_hashes.rs

@@ -1,6 +1,6 @@
 //! Hash representations of the `frame_metadata::v15::OuterEnums`.
 
-use std::collections::HashMap;
+use hashbrown::HashMap;
 
 use scale_info::{PortableRegistry, TypeDef};
 

metadata/src/utils/variant_index.rs

@@ -2,8 +2,10 @@
 // This file is dual-licensed as Apache-2.0 or GPL-3.0.
 // see LICENSE for license details.
 
+use alloc::borrow::ToOwned;
+use alloc::string::String;
+use hashbrown::HashMap;
 use scale_info::{form::PortableForm, PortableRegistry, TypeDef, Variant};
-use std::collections::HashMap;
 
 /// Given some type ID and type registry, build a couple of
 /// indexes to look up variants by index or name. If the ID provided
@@ -62,8 +64,8 @@ impl VariantIndex {
         types: &'a PortableRegistry,
     ) -> Option<&'a Variant<PortableForm>>
     where
-        String: std::borrow::Borrow<K>,
-        K: std::hash::Hash + Eq + ?Sized,
+        String: alloc::borrow::Borrow<K>,
+        K: core::hash::Hash + Eq + ?Sized,
     {
         let pos = *self.by_name.get(name)?;
         let variants = Self::get(variant_id, types)?;