rpcserver: Add invalidate/reconsiderblock support.

This implements the invalidateblock and reconsiderblock RPC commands
including the required help strings.

dcrjson/jsonrpcerr.go

@@ -77,6 +77,7 @@ const (
 	ErrRPCRawTxString       RPCErrorCode = -32602
 	ErrRPCDecodeHexString   RPCErrorCode = -22
 	ErrRPCDuplicateTx       RPCErrorCode = -40
+	ErrRPCReconsiderFailure RPCErrorCode = -50
 )
 
 // Errors that are specific to btcd.

internal/rpcserver/interface.go

@@ -408,6 +408,23 @@ type Chain interface {
 	// TSpendCountVotes returns the votes for the specified tspend up to
 	// the specified block.
 	TSpendCountVotes(*chainhash.Hash, *dcrutil.Tx) (int64, int64, error)
+
+	// InvalidateBlock manually invalidates the provided block as if the block
+	// had violated a consensus rule and marks all of its descendants as having
+	// a known invalid ancestor.  It then reorganizes the chain as necessary so
+	// the branch with the most cumulative proof of work that is still valid
+	// becomes the main chain.
+	InvalidateBlock(*chainhash.Hash) error
+
+	// ReconsiderBlock removes the known invalid status of the provided block
+	// and all of its ancestors along with the known invalid ancestor status
+	// from all of its descendants that are neither themselves marked as having
+	// failed validation nor descendants of another such block.  Therefore, it
+	// allows the affected blocks to be reconsidered under the current consensus
+	// rules.  It then potentially reorganizes the chain as necessary so the
+	// block with the most cumulative proof of work that is valid becomes the
+	// tip of the main chain.
+	ReconsiderBlock(*chainhash.Hash) error
 }
 
 // Clock represents a clock for use with the RPC server. The purpose of this

internal/rpcserver/rpcserver.go

@@ -200,10 +200,12 @@ var rpcHandlersBeforeInit = map[types.Method]commandHandler{
 	"gettxoutsetinfo":       handleGetTxOutSetInfo,
 	"getwork":               handleGetWork,
 	"help":                  handleHelp,
+	"invalidateblock":       handleInvalidateBlock,
 	"livetickets":           handleLiveTickets,
 	"missedtickets":         handleMissedTickets,
 	"node":                  handleNode,
 	"ping":                  handlePing,
+	"reconsiderblock":       handleReconsiderBlock,
 	"regentemplate":         handleRegenTemplate,
 	"searchrawtransactions": handleSearchRawTransactions,
 	"sendrawtransaction":    handleSendRawTransaction,
@@ -3889,6 +3891,35 @@ func handleHelp(_ context.Context, s *Server, cmd interface{}) (interface{}, err
 	return help, nil
 }
 
+// handleInvalidateBlock implements the invalidateblock command.
+func handleInvalidateBlock(_ context.Context, s *Server, cmd interface{}) (interface{}, error) {
+	c := cmd.(*types.InvalidateBlockCmd)
+	hash, err := chainhash.NewHashFromStr(c.BlockHash)
+	if err != nil {
+		return nil, rpcDecodeHexError(c.BlockHash)
+	}
+
+	chain := s.cfg.Chain
+	err = chain.InvalidateBlock(hash)
+	if err != nil {
+		if errors.Is(err, blockchain.ErrUnknownBlock) {
+			return nil, &dcrjson.RPCError{
+				Code:    dcrjson.ErrRPCBlockNotFound,
+				Message: fmt.Sprintf("Block not found: %v", hash),
+			}
+		}
+
+		if errors.Is(err, blockchain.ErrInvalidateGenesisBlock) {
+			return nil, rpcInvalidError("%v", err)
+		}
+
+		context := fmt.Sprintf("Failed to invalidate block %s", hash)
+		return nil, rpcInternalError(err.Error(), context)
+	}
+
+	return nil, nil
+}
+
 // handleLiveTickets implements the livetickets command.
 func handleLiveTickets(_ context.Context, s *Server, cmd interface{}) (interface{}, error) {
 	lt, err := s.cfg.Chain.LiveTickets()
@@ -3934,6 +3965,58 @@ func handlePing(_ context.Context, s *Server, cmd interface{}) (interface{}, err
 	return nil, nil
 }
 
+// handleReconsiderBlock implements the reconsiderblock command.
+func handleReconsiderBlock(_ context.Context, s *Server, cmd interface{}) (interface{}, error) {
+	c := cmd.(*types.ReconsiderBlockCmd)
+	hash, err := chainhash.NewHashFromStr(c.BlockHash)
+	if err != nil {
+		return nil, rpcDecodeHexError(c.BlockHash)
+	}
+
+	chain := s.cfg.Chain
+	err = chain.ReconsiderBlock(hash)
+	if err != nil {
+		if errors.Is(err, blockchain.ErrUnknownBlock) {
+			return nil, &dcrjson.RPCError{
+				Code:    dcrjson.ErrRPCBlockNotFound,
+				Message: fmt.Sprintf("Block not found: %v", hash),
+			}
+		}
+
+		// Use separate error code for failed validation.
+		allRuleErrs := func(err error) bool {
+			var rErr blockchain.RuleError
+			if !errors.As(err, &rErr) {
+				return false
+			}
+
+			var mErr blockchain.MultiError
+			if errors.As(err, &mErr) {
+				for _, e := range mErr {
+					if !errors.As(e, &rErr) {
+						return false
+					}
+				}
+			}
+
+			return true
+		}
+		if allRuleErrs(err) {
+			return nil, &dcrjson.RPCError{
+				Code: dcrjson.ErrRPCReconsiderFailure,
+				Message: fmt.Sprintf("Reconsidering block %s led to one or "+
+					"more validation failures: %v", hash, err),
+			}
+		}
+
+		// Fall back to an internal error.
+		context := fmt.Sprintf("Error while reconsidering block %s", hash)
+		return nil, rpcInternalError(err.Error(), context)
+	}
+
+	return nil, nil
+}
+
 // handleRegenTemplate implements the regentemplate command.
 func handleRegenTemplate(_ context.Context, s *Server, cmd interface{}) (interface{}, error) {
 	bt := s.cfg.BlockTemplater

internal/rpcserver/rpcserverhandlers_test.go

@@ -163,6 +163,7 @@ type testRPCChain struct {
 	headerByHeight                wire.BlockHeader
 	headerByHeightErr             error
 	heightRangeFn                 func(startHeight, endHeight int64) ([]chainhash.Hash, error)
+	invalidateBlockErr            error
 	isCurrent                     bool
 	liveTickets                   []chainhash.Hash
 	liveTicketsErr                error
@@ -176,6 +177,7 @@ type testRPCChain struct {
 	missedTicketsErr              error
 	nextThresholdState            blockchain.ThresholdStateTuple
 	nextThresholdStateErr         error
+	reconsiderBlockErr            error
 	stateLastChangedHeight        int64
 	stateLastChangedHeightErr     error
 	ticketPoolValue               dcrutil.Amount
@@ -321,6 +323,12 @@ func (c *testRPCChain) HeightRange(startHeight, endHeight int64) ([]chainhash.Ha
 	return c.heightRangeFn(startHeight, endHeight)
 }
 
+// InvalidateBlock returns a mocked error from manually invalidating a given
+// block.
+func (c *testRPCChain) InvalidateBlock(hash *chainhash.Hash) error {
+	return c.invalidateBlockErr
+}
+
 // IsCurrent returns a mocked bool representing whether or not the chain
 // believes it is current.
 func (c *testRPCChain) IsCurrent() bool {
@@ -368,6 +376,12 @@ func (c *testRPCChain) NextThresholdState(hash *chainhash.Hash, version uint32,
 	return c.nextThresholdState, c.nextThresholdStateErr
 }
 
+// ReconsiderBlock returns a mocked error from manually reconsidering a given
+// block.
+func (c *testRPCChain) ReconsiderBlock(hash *chainhash.Hash) error {
+	return c.reconsiderBlockErr
+}
+
 // StateLastChangedHeight returns a mocked height at which the provided
 // consensus deployment agenda last changed state.
 func (c *testRPCChain) StateLastChangedHeight(hash *chainhash.Hash, version uint32, deploymentID string) (int64, error) {

internal/rpcserver/rpcserverhelp.go

@@ -724,15 +724,25 @@ var helpDescsEnUS = map[string]string{
 	"help--result0":    "List of commands",
 	"help--result1":    "Help for specified command",
 
+	// InvalidateBlockCmd help.
+	"invalidateblock--synopsis": "Permanently invalidates a block as if it had violated consensus rules.\n" +
+		"Use reconsiderblock to remove the invalid status.",
+	"invalidateblock-blockhash": "The hash of the block to invalidate",
+
 	// PingCmd help.
 	"ping--synopsis": "Queues a ping to be sent to each connected peer.\n" +
 		"Ping times are provided by getpeerinfo via the pingtime and pingwait fields.",
 
 	// RebroadcastMissed help.
-	"rebroadcastmissed--synopsis": "Asks the daemon to rebroadcast missed votes.\n",
+	"rebroadcastmissed--synopsis": "Asks the daemon to rebroadcast missed votes.",
+
+	// RebroadcastWinnersCmd help.
+	"rebroadcastwinners--synopsis": "Asks the daemon to rebroadcast the winners of the voting lottery.",
 
-	// RebroadcastWinnerCmd help.
-	"rebroadcastwinners--synopsis": "Asks the daemon to rebroadcast the winners of the voting lottery.\n",
+	// ReconsiderBlockCmd help.
+	"reconsiderblock--synopsis": "Reconsiders a block for validation and best chain selection by removing any invalid status from it and its ancestors.\n" +
+		"Any descendants that are neither themselves marked as having failed validation, nor descendants of another such block, are also made eligibile for best chain selection.",
+	"reconsiderblock-blockhash": "The hash of the block to reconsider",
 
 	// SearchRawTransactionsCmd help.
 	"searchrawtransactions--synopsis": "Returns raw data for transactions involving the passed address.\n" +
@@ -1033,10 +1043,12 @@ var rpcResultTypes = map[types.Method][]interface{}{
 	"getwork":               {(*types.GetWorkResult)(nil), (*bool)(nil)},
 	"getcoinsupply":         {(*int64)(nil)},
 	"help":                  {(*string)(nil), (*string)(nil)},
+	"invalidateblock":       nil,
 	"livetickets":           {(*types.LiveTicketsResult)(nil)},
 	"missedtickets":         {(*types.MissedTicketsResult)(nil)},
 	"node":                  nil,
 	"ping":                  nil,
+	"reconsiderblock":       nil,
 	"regentemplate":         nil,
 	"searchrawtransactions": {(*string)(nil), (*[]types.SearchRawTransactionsResult)(nil)},
 	"sendrawtransaction":    {(*string)(nil)},