Merge pull request #1403 from ethereum/dev-083

backport v083 to dev

specs/networking/p2p-interface.md

@@ -160,7 +160,7 @@ Additional topics are used to propagate lower frequency validator messages. Thei
 
 #### Interop
 
-Unaggregated and aggregated attestations from all shards are sent to the `beacon_attestation` topic. Clients are not required to publish aggregate attestations but must be able to process them.
+Unaggregated and aggregated attestations from all shards are sent to the `beacon_attestation` topic. Clients are not required to publish aggregate attestations but must be able to process them. All validating clients SHOULD try to perform local attestation aggregation to prepare for block proposing.
 
 #### Mainnet
 
@@ -301,7 +301,7 @@ Here, `result` represents the 1-byte response code.
 
 The token of the negotiated protocol ID specifies the type of encoding to be used for the req/resp interaction. Two values are possible at this time:
 
--  `ssz`: The contents are [SSZ-encoded](../simple-serialize.md). This encoding type MUST be supported by all clients. For objects containing a single field, only the field is SSZ-encoded not a container with a single field. For example, the `BeaconBlocks` response would be an SSZ-encoded list of `BeaconBlock`s. All SSZ-Lists in the Req/Resp domain will have a maximum list size of `SSZ_MAX_LIST_SIZE`.
+-  `ssz`: the contents are [SSZ-encoded](#ssz-encoding). This encoding type MUST be supported by all clients. For objects containing a single field, only the field is SSZ-encoded not a container with a single field. For example, the `BeaconBlocks` response would be an SSZ-encoded list of `BeaconBlock`s. All SSZ-Lists in the Req/Resp domain will have a maximum list size of `SSZ_MAX_LIST_SIZE`.
 -  `ssz_snappy`: The contents are SSZ-encoded and then compressed with [Snappy](https://github.com/google/snappy). MAY be supported in the interoperability testnet; MUST be supported in mainnet.
 
 #### SSZ-encoding strategy (with or without Snappy)

specs/simple-serialize.md

@@ -63,7 +63,7 @@
 * **bitlist**: ordered variable-length collection of `boolean` values, limited to `N` bits
     * notation `Bitlist[N]`
 * **union**: union type containing one of the given subtypes
-    * notation `Union[type_1, type_2, ...]`, e.g. `union[null, uint64]`
+    * notation `Union[type_0, type_1, ...]`, e.g. `union[null, uint64]`
 
 ### Variable-size and fixed-size
 
@@ -79,8 +79,18 @@ For convenience we alias:
 * `null`: `{}`
 
 ### Default values
+Assuming a helper function `default(type)` which returns the default value for `type`, we can recursively define the default value for all types.
 
-The default value of a type upon initialization is recursively defined using `0` for `uintN`, `False` for `boolean` and the elements of `Bitvector`, and `[]` for lists and `Bitlist`. Unions default to the first type in the union (with type index zero), which is `null` if present in the union.
+| Type | Default Value |
+| ---- | ------------- |
+| `uintN` | `0` |
+| `boolean` | `False` |
+| `Container` | `[default(type) for type in container]` |
+| `Vector[type, N]` | `[default(type)] * N` |
+| `Bitvector[boolean, N]` | `[False] * N` |
+| `List[type, N]` | `[]` |
+| `Bitlist[boolean, N]` | `[]` |
+| `Union[type_0, type_1, ...]` | `default(type_0)` |
 
 #### `is_zero`
 

test_generators/ssz_generic/ssz_bitvector.py

@@ -5,11 +5,19 @@ from random import Random
 from eth2spec.debug.random_value import RandomizationMode, get_random_ssz_object
 
 
-def bitvector_case_fn(rng: Random, mode: RandomizationMode, size: int):
-    return get_random_ssz_object(rng, Bitvector[size],
+def bitvector_case_fn(rng: Random, mode: RandomizationMode, size: int, invalid_making_pos: int=None):
+    bits = get_random_ssz_object(rng, Bitvector[size],
                                  max_bytes_length=(size + 7) // 8,
                                  max_list_length=size,
                                  mode=mode, chaos=False)
+    if invalid_making_pos is not None and invalid_making_pos <= size:
+        already_invalid = False
+        for i in range(invalid_making_pos, size):
+            if bits[i]:
+                already_invalid = True
+        if not already_invalid:
+            bits[invalid_making_pos] = True
+    return bits
 
 
 def valid_cases():
@@ -23,8 +31,12 @@ def invalid_cases():
     # zero length bitvecors are illegal
     yield 'bitvec_0', invalid_test_case(lambda: b'')
     rng = Random(1234)
+    # Create a vector with test_size bits, but make the type typ_size instead,
+    # which is invalid when used with the given type size
+    # (and a bit set just after typ_size bits if necessary to avoid the valid 0 padding-but-same-last-byte case)
     for (typ_size, test_size) in [(1, 2), (2, 3), (3, 4), (4, 5),
                                   (5, 6), (8, 9), (9, 8), (16, 8), (32, 33), (512, 513)]:
         for mode in [RandomizationMode.mode_random, RandomizationMode.mode_zero, RandomizationMode.mode_max]:
             yield f'bitvec_{typ_size}_{mode.to_name()}_{test_size}', \
-                  invalid_test_case(lambda: serialize(bitvector_case_fn(rng, mode, test_size)))
+                  invalid_test_case(lambda: serialize(bitvector_case_fn(rng, mode, test_size,
+                                                                        invalid_making_pos=typ_size)))

test_libs/pyspec/eth2spec/debug/random_value.py

@@ -94,6 +94,8 @@ def get_random_ssz_object(rng: Random,
             length = 1
         elif mode == RandomizationMode.mode_max_count:
             length = max_list_length
+        elif mode == RandomizationMode.mode_nil_count:
+            length = 0
 
         if typ.length < length:  # SSZ imposes a hard limit on lists, we can't put in more than that
             length = typ.length