Surface the getVoteAccounts.epochCredits max-length constant in rpc-client-api

docs/src/developing/clients/jsonrpc-api.md

@@ -3265,7 +3265,7 @@ each containing an array of JSON objects with the following sub fields:
 - `epochVoteAccount: <bool>` - bool, whether the vote account is staked for this epoch
 - `commission: <number>`, percentage (0-100) of rewards payout owed to the vote account
 - `lastVote: <u64>` - Most recent slot voted on by this vote account
-- `epochCredits: <array>` - History of how many credits earned by the end of each epoch, as an array of arrays containing: `[epoch, credits, previousCredits]`
+- `epochCredits: <array>` - Latest history of earned credits for up to five epochs, as an array of arrays containing: `[epoch, credits, previousCredits]`.
 - `rootSlot: <u64>` - Current root slot for this vote account
 
 #### Example:

rpc-client-api/src/request.rs

@@ -204,6 +204,10 @@ pub const NUM_LARGEST_ACCOUNTS: usize = 20;
 pub const MAX_GET_PROGRAM_ACCOUNT_FILTERS: usize = 4;
 pub const MAX_GET_SLOT_LEADERS: usize = 5000;
 
+// Limit the length of the `epoch_credits` array for each validator in a `get_vote_accounts`
+// response
+pub const MAX_RPC_VOTE_ACCOUNT_INFO_EPOCH_CREDITS_HISTORY: usize = 5;
+
 // Validators that are this number of slots behind are considered delinquent
 pub const DELINQUENT_VALIDATOR_SLOT_DISTANCE: u64 = 128;
 

rpc-client-api/src/response.rs

@@ -374,7 +374,7 @@ pub struct RpcVoteAccountInfo {
     /// Whether this account is staked for the current epoch
     pub epoch_vote_account: bool,
 
-    /// History of how many credits earned by the end of each epoch
+    /// Latest history of earned credits for up to `MAX_RPC_VOTE_ACCOUNT_INFO_EPOCH_CREDITS_HISTORY` epochs
     ///   each tuple is (Epoch, credits, prev_credits)
     pub epoch_credits: Vec<(Epoch, u64, u64)>,
 

rpc/src/rpc.rs

@@ -35,7 +35,7 @@ use {
             MAX_GET_CONFIRMED_BLOCKS_RANGE, MAX_GET_CONFIRMED_SIGNATURES_FOR_ADDRESS2_LIMIT,
             MAX_GET_CONFIRMED_SIGNATURES_FOR_ADDRESS_SLOT_RANGE, MAX_GET_PROGRAM_ACCOUNT_FILTERS,
             MAX_GET_SIGNATURE_STATUSES_QUERY_ITEMS, MAX_GET_SLOT_LEADERS, MAX_MULTIPLE_ACCOUNTS,
-            NUM_LARGEST_ACCOUNTS,
+            MAX_RPC_VOTE_ACCOUNT_INFO_EPOCH_CREDITS_HISTORY, NUM_LARGEST_ACCOUNTS,
         },
         response::{Response as RpcResponse, *},
     },
@@ -115,10 +115,6 @@ type RpcCustomResult<T> = std::result::Result<T, RpcCustomError>;
 pub const MAX_REQUEST_BODY_SIZE: usize = 50 * (1 << 10); // 50kB
 pub const PERFORMANCE_SAMPLES_LIMIT: usize = 720;
 
-// Limit the length of the `epoch_credits` array for each validator in a `get_vote_accounts`
-// response
-const MAX_RPC_EPOCH_CREDITS_HISTORY: usize = 5;
-
 fn new_response<T>(bank: &Bank, value: T) -> RpcResponse<T> {
     RpcResponse {
         context: RpcResponseContext::new(bank.slot()),
@@ -958,10 +954,12 @@ impl JsonRpcRequestProcessor {
                 };
 
                 let epoch_credits = vote_state.epoch_credits();
-                let epoch_credits = if epoch_credits.len() > MAX_RPC_EPOCH_CREDITS_HISTORY {
+                let epoch_credits = if epoch_credits.len()
+                    > MAX_RPC_VOTE_ACCOUNT_INFO_EPOCH_CREDITS_HISTORY
+                {
                     epoch_credits
                         .iter()
-                        .skip(epoch_credits.len() - MAX_RPC_EPOCH_CREDITS_HISTORY)
+                        .skip(epoch_credits.len() - MAX_RPC_VOTE_ACCOUNT_INFO_EPOCH_CREDITS_HISTORY)
                         .cloned()
                         .collect()
                 } else {
@@ -7241,9 +7239,11 @@ pub mod tests {
             }
         }
 
-        // Overflow the epoch credits history and ensure only `MAX_RPC_EPOCH_CREDITS_HISTORY`
+        // Overflow the epoch credits history and ensure only `MAX_RPC_VOTE_ACCOUNT_INFO_EPOCH_CREDITS_HISTORY`
         // results are returned
-        for _ in 0..(TEST_SLOTS_PER_EPOCH * (MAX_RPC_EPOCH_CREDITS_HISTORY) as u64) {
+        for _ in
+            0..(TEST_SLOTS_PER_EPOCH * (MAX_RPC_VOTE_ACCOUNT_INFO_EPOCH_CREDITS_HISTORY) as u64)
+        {
             advance_bank();
         }
 
@@ -7263,7 +7263,7 @@ pub mod tests {
         assert!(!vote_account_status
             .current
             .iter()
-            .any(|x| x.epoch_credits.len() != MAX_RPC_EPOCH_CREDITS_HISTORY));
+            .any(|x| x.epoch_credits.len() != MAX_RPC_VOTE_ACCOUNT_INFO_EPOCH_CREDITS_HISTORY));
 
         // Advance bank with no voting
         rpc.advance_bank_to_confirmed_slot(bank.slot() + TEST_SLOTS_PER_EPOCH);