Add the ability to mark amendments as obsolete

src/ripple/app/misc/AmendmentTable.h

@@ -40,14 +40,14 @@ class AmendmentTable
  struct FeatureInfo
  {
  FeatureInfo() = delete;
- FeatureInfo(std::string const& n, uint256 const& f, DefaultVote v)
+ FeatureInfo(std::string const& n, uint256 const& f, VoteBehavior v)
  : name(n), feature(f), vote(v)
  {
  }
 
  std::string const name;
  uint256 const feature;
- DefaultVote const vote;
+ VoteBehavior const vote;
  };
 
  virtual ~AmendmentTable() = default;

src/ripple/app/misc/impl/AmendmentTable.cpp

@@ -333,19 +333,31 @@ AmendmentTableImpl::AmendmentTableImpl(
  }();
 
  // Parse supported amendments
- for (auto const& [name, amendment, defaultVote] : supported)
+ for (auto const& [name, amendment, votebehavior] : supported)
  {
  AmendmentState& s = add(amendment, lock);
 
  s.name = name;
  s.supported = true;
- s.vote = defaultVote == DefaultVote::yes ? AmendmentVote::up
- : AmendmentVote::down;
+ switch (votebehavior)
+ {
+ case VoteBehavior::DefaultYes:
+ s.vote = AmendmentVote::up;
+ break;
+
+ case VoteBehavior::DefaultNo:
+ s.vote = AmendmentVote::down;
+ break;
+
+ case VoteBehavior::Obsolete:
+ s.vote = AmendmentVote::obsolete;
+ break;
+ }
 
  JLOG(j_.debug()) << "Amendment " << amendment << " (" << s.name
  << ") is supported and will be "
  << (s.vote == AmendmentVote::up ? "up" : "down")
- << " voted if not enabled on the ledger.";
+ << " voted by default if not enabled on the ledger.";
  }
 
  hash_set<uint256> detect_conflict;
@@ -420,7 +432,9 @@ AmendmentTableImpl::AmendmentTableImpl(
  << amend_hash << "} is downvoted.";
  if (!amendment_name->empty())
  s->name = *amendment_name;
- s->vote = *vote;
+ // An obsolete amendment's vote can never be changed
+ if (s->vote != AmendmentVote::obsolete)
+ s->vote = *vote;
  }
  }
  else // up-vote
@@ -431,7 +445,9 @@ AmendmentTableImpl::AmendmentTableImpl(
  << amend_hash << "} is upvoted.";
  if (!amendment_name->empty())
  s.name = *amendment_name;
- s.vote = *vote;
+ // An obsolete amendment's vote can never be changed
+ if (s.vote != AmendmentVote::obsolete)
+ s.vote = *vote;
  }
  });
 }
@@ -489,6 +505,7 @@ AmendmentTableImpl::persistVote(
  std::string const& name,
  AmendmentVote vote) const
 {
+ assert(vote != AmendmentVote::obsolete);
  auto db = db_.checkoutDb();
  voteAmendment(*db, amendment, name, vote);
 }
@@ -499,7 +516,7 @@ AmendmentTableImpl::veto(uint256 const& amendment)
  std::lock_guard lock(mutex_);
  AmendmentState& s = add(amendment, lock);
 
- if (s.vote == AmendmentVote::down)
+ if (s.vote != AmendmentVote::up)
  return false;
  s.vote = AmendmentVote::down;
  persistVote(amendment, s.name, s.vote);
@@ -512,7 +529,7 @@ AmendmentTableImpl::unVeto(uint256 const& amendment)
  std::lock_guard lock(mutex_);
  AmendmentState* const s = get(amendment, lock);
 
- if (!s || s->vote == AmendmentVote::up)
+ if (!s || s->vote != AmendmentVote::down)
  return false;
  s->vote = AmendmentVote::up;
  persistVote(amendment, s->name, s->vote);
@@ -734,7 +751,13 @@ AmendmentTableImpl::injectJson(
  v[jss::name] = fs.name;
 
  v[jss::supported] = fs.supported;
- v[jss::vetoed] = fs.vote == AmendmentVote::down;
+ if (!fs.enabled)
+ {
+ if (fs.vote == AmendmentVote::obsolete)
+ v[jss::vetoed] = "Obsolete";
+ else
+ v[jss::vetoed] = fs.vote == AmendmentVote::down;
+ }
  v[jss::enabled] = fs.enabled;
 
  if (!fs.enabled && lastVote_)

src/ripple/app/rdb/Wallet.h

@@ -144,7 +144,7 @@ createFeatureVotes(soci::session& session);
 
 // For historical reasons the up-vote and down-vote integer representations
 // are unintuitive.
-enum class AmendmentVote : int { up = 0, down = 1 };
+enum class AmendmentVote : int { obsolete = -1, up = 0, down = 1 };
 
 /**
  * @brief readAmendments Reads all amendments from the FeatureVotes table.

src/ripple/protocol/Feature.h

@@ -36,17 +36,17 @@
  * for the feature at the bottom
  * 2) Add a uint256 definition for the feature to the corresponding source
  * file (Feature.cpp). Use `registerFeature` to create the feature with
- * the feature's name, `Supported::no`, and `DefaultVote::no`. This
+ * the feature's name, `Supported::no`, and `VoteBehavior::DefaultNo`. This
  * should be the only place the feature's name appears in code as a string.
  * 3) Use the uint256 as the parameter to `view.rules.enabled()` to
  * control flow into new code that this feature limits.
  * 4) If the feature development is COMPLETE, and the feature is ready to be
  * SUPPORTED, change the `registerFeature` parameter to Supported::yes.
  * 5) When the feature is ready to be ENABLED, change the `registerFeature`
- * parameter to `DefaultVote::yes`.
+ * parameter to `VoteBehavior::DefaultYes`.
  * In general, any newly supported amendments (`Supported::yes`) should have
- * a `DefaultVote::no` for at least one full release cycle. High priority
- * bug fixes can be an exception to this rule of thumb.
+ * a `VoteBehavior::DefaultNo` for at least one full release cycle. High
+ * priority bug fixes can be an exception to this rule of thumb.
  *
  * When a feature has been enabled for several years, the conditional code
  * may be removed, and the feature "retired". To retire a feature:
@@ -55,7 +55,7 @@
  * section at the end of the file.
  * 3) CHANGE the name of the variable to start with "retired".
  * 4) CHANGE the parameters of the `registerFeature` call to `Supported::yes`
- * and `DefaultVote::no`.
+ * and `VoteBehavior::DefaultNo`.
  * The feature must remain registered and supported indefinitely because it
  * still exists in the ledger, but there is no need to vote for it because
  * there's nothing to vote for. If it is removed completely from the code, any
@@ -66,7 +66,7 @@
 
 namespace ripple {
 
-enum class DefaultVote : bool { no = false, yes };
+enum class VoteBehavior : int { Obsolete = -1, DefaultNo = 0, DefaultYes };
 
 namespace detail {
 
@@ -79,7 +79,7 @@ static constexpr std::size_t numFeatures = 58;
 /** Amendments that this server supports and the default voting behavior.
  Whether they are enabled depends on the Rules defined in the validated
  ledger */
-std::map<std::string, DefaultVote> const&
+std::map<std::string, VoteBehavior> const&
 supportedAmendments();
 
 /** Amendments that this server won't vote for by default.

src/ripple/protocol/impl/Feature.cpp

@@ -67,9 +67,10 @@ enum class Supported : bool { no = false, yes };
 // updated.
 //
 // Generally, amendments which introduce new features should be set as
-// "DefaultVote::no" whereas in rare cases, amendments that fix critical
-// bugs should be set as "DefaultVote::yes", if off-chain consensus is
-// reached amongst reviewers, validator operators, and other participants.
+// "VoteBehavior::DefaultNo" whereas in rare cases, amendments that fix
+// critical bugs should be set as "VoteBehavior::DefaultYes", if off-chain
+// consensus is reached amongst reviewers, validator operators, and other
+// participants.
 
 class FeatureCollections
 {
@@ -115,7 +116,7 @@ class FeatureCollections
  // name, index, and uint256 feature identifier
  boost::multi_index::multi_index_container<Feature, feature_indexing>
  features;
- std::map<std::string, DefaultVote> supported;
+ std::map<std::string, VoteBehavior> supported;
  std::size_t upVotes = 0;
  std::size_t downVotes = 0;
  mutable std::atomic<bool> readOnly = false;
@@ -163,7 +164,7 @@ class FeatureCollections
  registerFeature(
  std::string const& name,
  Supported support,
- DefaultVote vote);
+ VoteBehavior vote);
 
  /** Tell FeatureCollections when registration is complete. */
  bool
@@ -181,7 +182,7 @@ class FeatureCollections
  /** Amendments that this server supports.
  Whether they are enabled depends on the Rules defined in the validated
  ledger */
- std::map<std::string, DefaultVote> const&
+ std::map<std::string, VoteBehavior> const&
  supportedAmendments() const
  {
  return supported;
@@ -230,11 +231,11 @@ uint256
 FeatureCollections::registerFeature(
  std::string const& name,
  Supported support,
- DefaultVote vote)
+ VoteBehavior vote)
 {
  check(!readOnly, "Attempting to register a feature after startup.");
  check(
- support == Supported::yes || vote == DefaultVote::no,
+ support == Supported::yes || vote == VoteBehavior::DefaultNo,
  "Invalid feature parameters. Must be supported to be up-voted.");
  Feature const* i = getByName(name);
  if (!i)
@@ -254,7 +255,7 @@ FeatureCollections::registerFeature(
  {
  supported.emplace(name, vote);
 
- if (vote == DefaultVote::yes)
+ if (vote == VoteBehavior::DefaultYes)
  ++upVotes;
  else
  ++downVotes;
@@ -315,7 +316,7 @@ static FeatureCollections featureCollections;
 /** Amendments that this server supports.
  Whether they are enabled depends on the Rules defined in the validated
  ledger */
-std::map<std::string, DefaultVote> const&
+std::map<std::string, VoteBehavior> const&
 detail::supportedAmendments()
 {
  return featureCollections.supportedAmendments();
@@ -344,7 +345,7 @@ getRegisteredFeature(std::string const& name)
 }
 
 uint256
-registerFeature(std::string const& name, Supported support, DefaultVote vote)
+registerFeature(std::string const& name, Supported support, VoteBehavior vote)
 {
  return featureCollections.registerFeature(name, support, vote);
 }
@@ -354,7 +355,7 @@ registerFeature(std::string const& name, Supported support, DefaultVote vote)
 uint256
 retireFeature(std::string const& name)
 {
- return registerFeature(name, Supported::yes, DefaultVote::no);
+ return registerFeature(name, Supported::yes, VoteBehavior::Obsolete);
 }
 
 /** Tell FeatureCollections when registration is complete. */
@@ -390,9 +391,9 @@ Takes the name of a feature, whether it's supported, and the default vote. Will
 register the feature, and create a variable whose name is "feature" plus the
 feature name.
 */
-#define REGISTER_FEATURE(fName, supported, defaultvote) \
- uint256 const feature##fName = \
- registerFeature(#fName, supported, defaultvote)
+#define REGISTER_FEATURE(fName, supported, votebehavior) \
+ uint256 const feature##fName =  \
+ registerFeature(#fName, supported, votebehavior)
 
 #pragma push_macro("REGISTER_FIX")
 #undef REGISTER_FIX
@@ -402,59 +403,71 @@ Takes the name of a feature, whether it's supported, and the default vote. Will
 register the feature, and create a variable whose name is the unmodified feature
 name.
 */
-#define REGISTER_FIX(fName, supported, defaultvote) \
- uint256 const fName = registerFeature(#fName, supported, defaultvote)
+#define REGISTER_FIX(fName, supported, votebehavior) \
+ uint256 const fName = registerFeature(#fName, supported, votebehavior)
 
 // clang-format off
 
 // All known amendments must be registered either here or below with the
 // "retired" amendments
-REGISTER_FEATURE(OwnerPaysFee, Supported::no, DefaultVote::no);
-REGISTER_FEATURE(Flow, Supported::yes, DefaultVote::yes);
-REGISTER_FEATURE(FlowCross, Supported::yes, DefaultVote::yes);
-REGISTER_FEATURE(CryptoConditionsSuite, Supported::yes, DefaultVote::no);
-REGISTER_FIX (fix1513, Supported::yes, DefaultVote::yes);
-REGISTER_FEATURE(DepositAuth, Supported::yes, DefaultVote::yes);
-REGISTER_FEATURE(Checks, Supported::yes, DefaultVote::yes);
-REGISTER_FIX (fix1571, Supported::yes, DefaultVote::yes);
-REGISTER_FIX (fix1543, Supported::yes, DefaultVote::yes);
-REGISTER_FIX (fix1623, Supported::yes, DefaultVote::yes);
-REGISTER_FEATURE(DepositPreauth, Supported::yes, DefaultVote::yes);
+REGISTER_FEATURE(OwnerPaysFee, Supported::no, VoteBehavior::DefaultNo);
+REGISTER_FEATURE(Flow, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FEATURE(FlowCross, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FIX (fix1513, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FEATURE(DepositAuth, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FEATURE(Checks, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FIX (fix1571, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FIX (fix1543, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FIX (fix1623, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FEATURE(DepositPreauth, Supported::yes, VoteBehavior::DefaultYes);
 // Use liquidity from strands that consume max offers, but mark as dry
-REGISTER_FIX (fix1515, Supported::yes, DefaultVote::yes);
-REGISTER_FIX (fix1578, Supported::yes, DefaultVote::yes);
-REGISTER_FEATURE(MultiSignReserve, Supported::yes, DefaultVote::yes);
-REGISTER_FIX (fixTakerDryOfferRemoval, Supported::yes, DefaultVote::yes);
-REGISTER_FIX (fixMasterKeyAsRegularKey, Supported::yes, DefaultVote::yes);
-REGISTER_FIX (fixCheckThreading, Supported::yes, DefaultVote::yes);
-REGISTER_FIX (fixPayChanRecipientOwnerDir, Supported::yes, DefaultVote::yes);
-REGISTER_FEATURE(DeletableAccounts, Supported::yes, DefaultVote::yes);
+REGISTER_FIX (fix1515, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FIX (fix1578, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FEATURE(MultiSignReserve, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FIX (fixTakerDryOfferRemoval, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FIX (fixMasterKeyAsRegularKey, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FIX (fixCheckThreading, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FIX (fixPayChanRecipientOwnerDir, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FEATURE(DeletableAccounts, Supported::yes, VoteBehavior::DefaultYes);
 // fixQualityUpperBound should be activated before FlowCross
-REGISTER_FIX (fixQualityUpperBound, Supported::yes, DefaultVote::yes);
-REGISTER_FEATURE(RequireFullyCanonicalSig, Supported::yes, DefaultVote::yes);
+REGISTER_FIX (fixQualityUpperBound, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FEATURE(RequireFullyCanonicalSig, Supported::yes, VoteBehavior::DefaultYes);
 // fix1781: XRPEndpointSteps should be included in the circular payment check
-REGISTER_FIX (fix1781, Supported::yes, DefaultVote::yes);
-REGISTER_FEATURE(HardenedValidations, Supported::yes, DefaultVote::yes);
-REGISTER_FIX (fixAmendmentMajorityCalc, Supported::yes, DefaultVote::yes);
-REGISTER_FEATURE(NegativeUNL, Supported::yes, DefaultVote::yes);
-REGISTER_FEATURE(TicketBatch, Supported::yes, DefaultVote::yes);
-REGISTER_FEATURE(FlowSortStrands, Supported::yes, DefaultVote::yes);
-REGISTER_FIX (fixSTAmountCanonicalize, Supported::yes, DefaultVote::yes);
-REGISTER_FIX (fixRmSmallIncreasedQOffers, Supported::yes, DefaultVote::yes);
-REGISTER_FEATURE(CheckCashMakesTrustLine, Supported::yes, DefaultVote::no);
-REGISTER_FEATURE(NonFungibleTokensV1, Supported::yes, DefaultVote::no);
-REGISTER_FEATURE(ExpandedSignerList, Supported::yes, DefaultVote::no);
-REGISTER_FIX (fixNFTokenDirV1, Supported::yes, DefaultVote::no);
-REGISTER_FIX (fixNFTokenNegOffer, Supported::yes, DefaultVote::no);
-REGISTER_FEATURE(NonFungibleTokensV1_1, Supported::yes, DefaultVote::no);
-REGISTER_FIX (fixTrustLinesToSelf, Supported::yes, DefaultVote::no);
-REGISTER_FIX (fixRemoveNFTokenAutoTrustLine, Supported::yes, DefaultVote::yes);
-REGISTER_FEATURE(ImmediateOfferKilled, Supported::yes, DefaultVote::no);
-REGISTER_FEATURE(DisallowIncoming, Supported::yes, DefaultVote::no);
-REGISTER_FEATURE(XRPFees, Supported::yes, DefaultVote::no);
-REGISTER_FIX (fixUniversalNumber, Supported::yes, DefaultVote::no);
-REGISTER_FIX (fixNonFungibleTokensV1_2, Supported::yes, DefaultVote::no);
-REGISTER_FIX (fixNFTokenRemint, Supported::yes, DefaultVote::no);
+REGISTER_FIX (fix1781, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FEATURE(HardenedValidations, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FIX (fixAmendmentMajorityCalc, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FEATURE(NegativeUNL, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FEATURE(TicketBatch, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FEATURE(FlowSortStrands, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FIX (fixSTAmountCanonicalize, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FIX (fixRmSmallIncreasedQOffers, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FEATURE(CheckCashMakesTrustLine, Supported::yes, VoteBehavior::DefaultNo);
+REGISTER_FEATURE(ExpandedSignerList, Supported::yes, VoteBehavior::DefaultNo);
+REGISTER_FEATURE(NonFungibleTokensV1_1, Supported::yes, VoteBehavior::DefaultNo);
+REGISTER_FIX (fixTrustLinesToSelf, Supported::yes, VoteBehavior::DefaultNo);
+REGISTER_FIX (fixRemoveNFTokenAutoTrustLine, Supported::yes, VoteBehavior::DefaultYes);
+REGISTER_FEATURE(ImmediateOfferKilled, Supported::yes, VoteBehavior::DefaultNo);
+REGISTER_FEATURE(DisallowIncoming, Supported::yes, VoteBehavior::DefaultNo);
+REGISTER_FEATURE(XRPFees, Supported::yes, VoteBehavior::DefaultNo);
+REGISTER_FIX (fixUniversalNumber, Supported::yes, VoteBehavior::DefaultNo);
+REGISTER_FIX (fixNonFungibleTokensV1_2, Supported::yes, VoteBehavior::DefaultNo);
+REGISTER_FIX (fixNFTokenRemint, Supported::yes, VoteBehavior::DefaultNo);
+
+// The following amendments are obsolete, but must remain supported
+// because they could potentially get enabled.
+//
+// Obsolete features are (usually) not in the ledger, and may have code
+// controlled by the feature. They need to be supported because at some
+// time in the past, the feature was supported and votable, but never
+// passed. So the feature needs to be supported in case it is ever
+// enabled (added to the ledger).
+//
+// If a feature remains obsolete for long enough that no clients are able
+// to vote for it, the feature can be removed (entirely?) from the code.
+REGISTER_FEATURE(CryptoConditionsSuite, Supported::yes, VoteBehavior::Obsolete);
+REGISTER_FEATURE(NonFungibleTokensV1, Supported::yes, VoteBehavior::Obsolete);
+REGISTER_FIX (fixNFTokenDirV1, Supported::yes, VoteBehavior::Obsolete);
+REGISTER_FIX (fixNFTokenNegOffer, Supported::yes, VoteBehavior::Obsolete);
 
 // The following amendments have been active for at least two years. Their
 // pre-amendment code has been removed and the identifiers are deprecated.