feat: validate SSZ schemas for containers

config/config.exs

@@ -34,3 +34,8 @@ config :lambda_ethereum_consensus, BeaconApi.Endpoint,
     formats: [json: BeaconApi.ErrorJSON],
     layout: false
   ]
+
+# Load minimal config by default, to allow schema checking
+config :lambda_ethereum_consensus, ChainSpec,
+  config: MinimalConfig,
+  genesis_validators_root: <<0::256>>

lib/container.ex

@@ -9,4 +9,16 @@ defmodule LambdaEthereumConsensus.Container do
     It specifies both the serialization order and the schema for each key in the map.
   """
   @callback schema() :: Keyword.t(SszEx.schema())
+
+  defmacro __using__(_opts) do
+    quote do
+      @behaviour unquote(__MODULE__)
+
+      @after_compile unquote(__MODULE__)
+    end
+  end
+
+  def __after_compile__(env, _bytecode) do
+    SszEx.validate_schema!(env.module)
+  end
 end

lib/ssz_ex.ex

@@ -35,6 +35,7 @@ defmodule LambdaEthereumConsensus.SszEx do
   #################
   import Bitwise
 
+  @allowed_uints [8, 16, 32, 64, 128, 256]
   @bytes_per_chunk 32
   @bits_per_byte 8
   @bits_per_chunk @bytes_per_chunk * @bits_per_byte
@@ -48,6 +49,41 @@ defmodule LambdaEthereumConsensus.SszEx do
   @spec hash_nodes(binary(), binary()) :: binary()
   def hash_nodes(left, right), do: :crypto.hash(:sha256, left <> right)
 
+  @spec validate_schema!(schema()) :: :ok
+  def validate_schema!(:bool), do: :ok
+  def validate_schema!({:int, n}) when n in @allowed_uints, do: :ok
+  def validate_schema!({:bytes, size}) when size > 0, do: :ok
+  def validate_schema!({:byte_list, size}) when size > 0, do: :ok
+  def validate_schema!({:list, :bytes, size}) when size > 0, do: :ok
+  def validate_schema!({:vector, :bytes, size}) when size > 0, do: :ok
+  def validate_schema!({:list, sub, size}) when size > 0, do: validate_schema!(sub)
+  def validate_schema!({:vector, sub, size}) when size > 0, do: validate_schema!(sub)
+  def validate_schema!({:bitlist, size}) when size > 0, do: :ok
+  def validate_schema!({:bitvector, size}) when size > 0, do: :ok
+
+  def validate_schema!(module) when is_atom(module) do
+    schema = module.schema()
+    # validate each sub-schema
+    {fields, subschemas} = Enum.unzip(schema)
+    Enum.each(subschemas, &validate_schema!/1)
+
+    # check the struct field names match the schema keys
+    struct_fields =
+      module.__struct__() |> Map.keys() |> MapSet.new() |> MapSet.delete(:__struct__)
+
+    fields = MapSet.new(fields)
+
+    if MapSet.equal?(fields, struct_fields) do
+      :ok
+    else
+      missing =
+        MapSet.symmetric_difference(fields, struct_fields)
+        |> Enum.map_join(", ", &inspect/1)
+
+      raise "The struct and its schema differ by some fields: #{missing}"
+    end
+  end
+
   @spec encode(any(), schema()) :: {:ok, binary()} | {:error, String.t()}
   def encode(value, {:int, size}), do: encode_int(value, size)
   def encode(value, :bool), do: encode_bool(value)

lib/types/beacon_chain/attestation.ex

@@ -5,7 +5,7 @@ defmodule Types.Attestation do
   """
   alias LambdaEthereumConsensus.Utils.BitList
 
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :aggregation_bits,

lib/types/beacon_chain/attestation_data.ex

@@ -4,7 +4,7 @@ defmodule Types.AttestationData do
   Related definitions in `native/ssz_nif/src/types/`.
   """
 
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :slot,

lib/types/beacon_chain/attester_slashing.ex

@@ -3,7 +3,7 @@ defmodule Types.AttesterSlashing do
   Struct definition for `AttesterSlashing`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :attestation_1,

lib/types/beacon_chain/beacon_block.ex

@@ -3,7 +3,7 @@ defmodule Types.BeaconBlock do
   Struct definition for `BeaconBlock`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   alias Types.BeaconBlockBody
 

lib/types/beacon_chain/beacon_block_body.ex

@@ -3,7 +3,7 @@ defmodule Types.BeaconBlockBody do
   Struct definition for `BeaconBlockBody`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :randao_reveal,

lib/types/beacon_chain/beacon_block_body_deneb.ex

@@ -3,7 +3,7 @@ defmodule Types.BeaconBlockBodyDeneb do
   Struct definition for `BeaconBlockBody`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :randao_reveal,
@@ -63,7 +63,8 @@ defmodule Types.BeaconBlockBodyDeneb do
       {:execution_payload, Types.ExecutionPayloadDeneb},
       {:bls_to_execution_changes,
        {:list, Types.BLSToExecutionChange, ChainSpec.get("MAX_BLS_TO_EXECUTION_CHANGES")}},
-      {:blob_kzg_commitments, {:list, TypeAliases.kzg_commitment()}}
+      {:blob_kzg_commitments,
+       {:list, TypeAliases.kzg_commitment(), ChainSpec.get("MAX_BLOB_COMMITMENTS_PER_BLOCK")}}
     ]
   end
 end

lib/types/beacon_chain/beacon_block_deneb.ex

@@ -3,7 +3,7 @@ defmodule Types.BeaconBlockDeneb do
   Struct definition for `BeaconBlock`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :slot,

lib/types/beacon_chain/beacon_block_header.ex

@@ -3,7 +3,7 @@ defmodule Types.BeaconBlockHeader do
   Struct definition for `BeaconBlockHeader`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :slot,

lib/types/beacon_chain/beacon_state.ex

@@ -137,7 +137,7 @@ defmodule Types.BeaconState do
   end
 
   unless HardForkAliasInjection.deneb?() do
-    @behaviour LambdaEthereumConsensus.Container
+    use LambdaEthereumConsensus.Container
 
     alias LambdaEthereumConsensus.StateTransition.Accessors, warn: false
     alias LambdaEthereumConsensus.StateTransition.Predicates, warn: false

lib/types/beacon_chain/beacon_state_deneb.ex

@@ -137,7 +137,7 @@ defmodule Types.BeaconStateDeneb do
   end
 
   if HardForkAliasInjection.deneb?() do
-    @behaviour LambdaEthereumConsensus.Container
+    use LambdaEthereumConsensus.Container
 
     alias LambdaEthereumConsensus.StateTransition.Accessors, warn: false
     alias LambdaEthereumConsensus.StateTransition.Predicates, warn: false

lib/types/beacon_chain/blob_identifier.ex

@@ -3,7 +3,7 @@ defmodule Types.BlobIdentifier do
   Struct definition for `BlobIdentifier`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :block_root,

lib/types/beacon_chain/blob_sidecar.ex

@@ -3,7 +3,7 @@ defmodule Types.BlobSidecar do
   Struct definition for `BlobSidecar`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :index,

lib/types/beacon_chain/bls_to_execution_change.ex

@@ -3,7 +3,7 @@ defmodule Types.BLSToExecutionChange do
   Struct definition for `BLSToExecutionChange`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :validator_index,

lib/types/beacon_chain/checkpoint.ex

@@ -4,7 +4,8 @@ defmodule Types.Checkpoint do
   Related definitions in `native/ssz_nif/src/types/`.
   """
 
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
+
   fields = [
     :root,
     :epoch

lib/types/beacon_chain/deposit.ex

@@ -3,7 +3,7 @@ defmodule Types.Deposit do
   Struct definition for `Deposit`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :proof,

lib/types/beacon_chain/deposit_data.ex

@@ -3,7 +3,7 @@ defmodule Types.DepositData do
   Struct definition for `DepositData`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :pubkey,

lib/types/beacon_chain/deposit_message.ex

@@ -3,7 +3,7 @@ defmodule Types.DepositMessage do
   Struct definition for `DepositMessage`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :pubkey,

lib/types/beacon_chain/eth1_data.ex

@@ -3,7 +3,7 @@ defmodule Types.Eth1Data do
   Struct definition for `Eth1Data`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :deposit_root,

lib/types/beacon_chain/execution_payload.ex

@@ -3,7 +3,7 @@ defmodule Types.ExecutionPayload do
   Struct definition for `ExecutionPayload`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :parent_hash,

lib/types/beacon_chain/execution_payload_deneb.ex

@@ -3,7 +3,7 @@ defmodule Types.ExecutionPayloadDeneb do
   Struct definition for `ExecutionPayload`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :parent_hash,

lib/types/beacon_chain/execution_payload_header.ex

@@ -3,7 +3,7 @@ defmodule Types.ExecutionPayloadHeader do
   Struct definition for `ExecutionPayloadHeader`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   @default_execution_payload_header %{
     parent_hash: <<0::256>>,

lib/types/beacon_chain/execution_payload_header_deneb.ex

@@ -3,7 +3,7 @@ defmodule Types.ExecutionPayloadHeaderDeneb do
   Struct definition for `ExecutionPayloadHeader`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   @default_execution_payload_header %{
     parent_hash: <<0::256>>,

lib/types/beacon_chain/fork.ex

@@ -4,7 +4,7 @@ defmodule Types.Fork do
   Related definitions in `native/ssz_nif/src/types/`.
   """
 
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :previous_version,

lib/types/beacon_chain/fork_data.ex

@@ -4,7 +4,7 @@ defmodule Types.ForkData do
   Related definitions in `native/ssz_nif/src/types/`.
   """
 
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :current_version,

lib/types/beacon_chain/historical_batch.ex

@@ -3,7 +3,7 @@ defmodule Types.HistoricalBatch do
   Struct definition for `HistoricalBatch`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :block_roots,

lib/types/beacon_chain/historical_summary.ex

@@ -5,7 +5,7 @@ defmodule Types.HistoricalSummary do
   `HistoricalSummary` matches the components of the phase0 `HistoricalBatch`
     making the two hash_tree_root-compatible.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :block_summary_root,

lib/types/beacon_chain/indexed_attestation.ex

@@ -3,7 +3,7 @@ defmodule Types.IndexedAttestation do
   Struct definition for `IndexedAttestation`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :attesting_indices,

lib/types/beacon_chain/pending_attestation.ex

@@ -5,7 +5,7 @@ defmodule Types.PendingAttestation do
   """
   alias LambdaEthereumConsensus.Utils.BitList
 
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :aggregation_bits,

lib/types/beacon_chain/proposer_slashing.ex

@@ -3,7 +3,7 @@ defmodule Types.ProposerSlashing do
   Struct definition for `ProposerSlashing`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :signed_header_1,

lib/types/beacon_chain/signed_beacon_block.ex

@@ -3,7 +3,7 @@ defmodule Types.SignedBeaconBlock do
   Struct definition for `SignedBeaconBlock`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :message,

lib/types/beacon_chain/signed_beacon_block_deneb.ex

@@ -3,7 +3,7 @@ defmodule Types.SignedBeaconBlockDeneb do
   Struct definition for `SignedBeaconBlock`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :message,

lib/types/beacon_chain/signed_beacon_block_header.ex

@@ -3,7 +3,7 @@ defmodule Types.SignedBeaconBlockHeader do
   Struct definition for `SignedBeaconBlockHeader`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :message,

lib/types/beacon_chain/signed_bls_to_execution_change.ex

@@ -3,7 +3,7 @@ defmodule Types.SignedBLSToExecutionChange do
   Struct definition for `SignedBLSToExecutionChange`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :message,

lib/types/beacon_chain/signed_voluntary_exit.ex

@@ -3,7 +3,7 @@ defmodule Types.SignedVoluntaryExit do
   Struct definition for `SignedVoluntaryExit`.
   Related definitions in `native/ssz_nif/src/types/`.
   """
-  @behaviour LambdaEthereumConsensus.Container
+  use LambdaEthereumConsensus.Container
 
   fields = [
     :message,