Fuzz Testing: rust-cid::varint_read_u64 panics on unwrap in no_std en…

…vironment (#1719)

# Goal
The goal of this PR is to eliminate a panic discovered in fuzz testing.
Closes #1712 
# Discussion
A PR was created in `multiformats/rust-cid` and merged to refactor
`unwrap()` to return a Result in a `no_std` environment.
See PR here:
[multiformats/rust-cid/pull/145](multiformats/rust-cid#145)

`Cargo.toml` was updated to be pinned to the PR commit with the fix in
`rust-cid`

# Checklist
- [ ] Chain spec updated
- [ ] Custom RPC OR Runtime API added/changed? Updated js/api-augment.
- [ ] Design doc(s) updated
- [x] Tests added
- [ ] Benchmarks added
- [ ] Weights updated

---------

Co-authored-by: Matthew Orris <--help>

.vscode/settings.json

@@ -13,5 +13,8 @@
         "lruntime",
         "pkill"
     ],
-    "rust-analyzer.showUnlinkedFileNotification": false
+    // Set the features to use for cargo commands
+    "rust-analyzer.cargo.features": [
+        "frequency-no-relay"
+    ]
 }

pallets/messages/Cargo.toml

@@ -30,7 +30,8 @@ sp-runtime = { git = "https://github.com/paritytech/substrate", default-features
 sp-std = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "polkadot-v0.9.43" }
 # Frequency related dependencies
 common-primitives = { default-features = false, path = "../../common/primitives" }
-cid = { version = "0.10.1", default-features = false }
+# Pinning a specific commit to fix an unwrap-panic issue: REVIEW: remove when cid > 0.10.1 
+cid = { git = "https://github.com/multiformats/rust-cid", rev = "86c79126d851316350ad106d0df3e4ae69071874", default-features = false}
 multibase = { version ="0.9", default-features = false }
 
 [dev-dependencies]

pallets/messages/src/tests/other_tests.rs

@@ -657,6 +657,16 @@ fn validate_cid_not_correct_format_errors() {
 	})
 }
 
+#[test]
+fn validate_cid_unwrap_panics() {
+	new_test_ext().execute_with(|| {
+		// This should not panic, but should return an error.
+		let bad_cid = vec![102, 70, 70, 70, 70, 70, 70, 70, 70, 48, 48, 48, 54, 53, 53, 48, 48];
+
+		assert_noop!(MessagesPallet::validate_cid(&bad_cid), Error::<Test>::InvalidCid);
+	})
+}
+
 #[test]
 fn map_to_response_on_chain() {
 	let payload_vec = b"123456789012345678901234567890".to_vec();