Add blobs as oracle records (#2162)

## Motivation

We'll need blobs are oracles to be able to properly check things for #2151. Fixes #2032

## Proposal

Add blobs as oracles

## Test Plan

CI + will be used in following PRs

linera-base/src/data_types.rs

@@ -718,24 +718,43 @@ pub struct OracleRecord {
     pub responses: Vec<OracleResponse>,
 }
 
+impl OracleRecord {
+    /// Wether an `OracleRecord` is permitted in fast blocks or not.
+    pub fn is_permitted_in_fast_blocks(&self) -> bool {
+        self.responses
+            .iter()
+            .all(|oracle_response| oracle_response.is_permitted_in_fast_blocks())
+    }
+}
+
 /// A record of a single oracle response.
 #[derive(Debug, PartialEq, Eq, Hash, Clone, Serialize, Deserialize)]
 pub enum OracleResponse {
     /// The response from a service query.
     Service(Vec<u8>),
     /// The response from an HTTP POST request.
     Post(Vec<u8>),
+    /// A successful read or write of a blob.
+    Blob(BlobId),
     /// An assertion oracle that passed.
     Assert,
 }
 
+impl OracleResponse {
+    /// Wether an `OracleResponse` is permitted in fast blocks or not.
+    pub fn is_permitted_in_fast_blocks(&self) -> bool {
+        matches!(self, OracleResponse::Blob(_))
+    }
+}
+
 impl fmt::Display for OracleResponse {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
             OracleResponse::Service(bytes) => {
                 write!(f, "Service:{}", STANDARD_NO_PAD.encode(bytes))?
             }
             OracleResponse::Post(bytes) => write!(f, "Post:{}", STANDARD_NO_PAD.encode(bytes))?,
+            OracleResponse::Blob(blob_id) => write!(f, "Blob:{}", blob_id)?,
             OracleResponse::Assert => write!(f, "Assert")?,
         };
 
@@ -757,6 +776,9 @@ impl std::str::FromStr for OracleResponse {
                 STANDARD_NO_PAD.decode(string).context("Invalid base64")?,
             ));
         }
+        if let Some(string) = s.strip_prefix("Blob:") {
+            return Ok(OracleResponse::Blob(BlobId(CryptoHash::from_str(string)?)));
+        }
         Err(anyhow::anyhow!("Invalid enum! Enum: {}", s))
     }
 }

linera-core/src/chain_worker/state.rs

@@ -355,9 +355,11 @@ where
                 .ok_or_else(|| WorkerError::InvalidLiteCertificate)?;
         }
         if round.is_fast() {
-            let mut records = outcome.oracle_records.iter();
             ensure!(
-                records.all(|record| record.responses.is_empty()),
+                outcome
+                    .oracle_records
+                    .iter()
+                    .all(|record| record.is_permitted_in_fast_blocks()),
                 WorkerError::FastBlockUsingOracles
             );
         }

linera-execution/src/execution.rs

@@ -296,7 +296,7 @@ where
         assert_eq!(context.chain_id, self.context().extra().chain_id());
         match operation {
             Operation::System(op) => {
-                let (mut result, new_application) =
+                let (mut result, new_application, returned_oracle_record) =
                     self.system.execute_operation(context, op).await?;
                 result.authenticated_signer = context.authenticated_signer;
                 result.refund_grant_to = context.refund_grant_to();
@@ -318,7 +318,7 @@ where
                     outcomes.extend(user_outcomes);
                     return Ok((outcomes, oracle_record));
                 }
-                Ok((outcomes, OracleRecord::default()))
+                Ok((outcomes, returned_oracle_record))
             }
             Operation::User {
                 application_id,

linera-execution/src/system.rs

@@ -12,7 +12,9 @@ use async_graphql::Enum;
 use custom_debug_derive::Debug;
 use linera_base::{
     crypto::{CryptoHash, PublicKey},
-    data_types::{Amount, ApplicationPermissions, ArithmeticError, Timestamp},
+    data_types::{
+        Amount, ApplicationPermissions, ArithmeticError, OracleRecord, OracleResponse, Timestamp,
+    },
     ensure, hex_debug,
     identifiers::{Account, BlobId, BytecodeId, ChainDescription, ChainId, MessageId, Owner},
     ownership::{ChainOwnership, TimeoutConfig},
@@ -443,12 +445,16 @@ where
         (
             RawExecutionOutcome<SystemMessage, Amount>,
             Option<(UserApplicationId, Vec<u8>)>,
+            OracleRecord,
         ),
         SystemExecutionError,
     > {
         use SystemOperation::*;
         let mut outcome = RawExecutionOutcome::default();
         let mut new_application = None;
+        let mut oracle_record = OracleRecord {
+            responses: Vec::new(),
+        };
         match operation {
             OpenChain(config) => {
                 let next_message_id = context.next_message_id();
@@ -672,10 +678,12 @@ where
                 };
                 outcome.messages.push(message);
             }
-            PublishBlob { .. } => (),
+            PublishBlob { blob_id } => {
+                oracle_record.responses.push(OracleResponse::Blob(blob_id));
+            }
         }
 
-        Ok((outcome, new_application))
+        Ok((outcome, new_application, oracle_record))
     }
 
     pub async fn transfer(
@@ -1074,7 +1082,7 @@ mod tests {
             contract: Bytecode::new(vec![]),
             service: Bytecode::new(vec![]),
         };
-        let (result, new_application) = view
+        let (result, new_application, _) = view
             .system
             .execute_operation(context, operation)
             .await
@@ -1112,7 +1120,7 @@ mod tests {
             instantiation_argument: vec![],
             required_application_ids: vec![],
         };
-        let (result, new_application) = view
+        let (result, new_application, _) = view
             .system
             .execute_operation(context, operation)
             .await
@@ -1149,7 +1157,7 @@ mod tests {
             application_permissions: Default::default(),
         };
         let operation = SystemOperation::OpenChain(config.clone());
-        let (result, new_application) = view
+        let (result, new_application, _) = view
             .system
             .execute_operation(context, operation)
             .await

linera-rpc/tests/snapshots/format__format.yaml.snap

@@ -651,6 +651,10 @@ OracleResponse:
         NEWTYPE:
           SEQ: U8
     2:
+      Blob:
+        NEWTYPE:
+          TYPENAME: BlobId
+    3:
       Assert: UNIT
 Origin:
   STRUCT: