Fix the decoding of unsigned transactions (#243)

* Recover sender address only for signed transactions

* Add a test case for decoding an unsigned transaction

* Add a test case for an EIP-2930 transaction

lib/eth/tx/eip1559.rb

@@ -186,11 +186,16 @@ def decode(hex)
         # last but not least, set the type.
         @type = TYPE_1559
 
-        # recover sender address
-        v = Chain.to_v recovery_id, chain_id
-        public_key = Signature.recover(unsigned_hash, "#{r.rjust(64, "0")}#{s.rjust(64, "0")}#{v.to_s(16)}", chain_id)
-        address = Util.public_key_to_address(public_key).to_s
-        @sender = Tx.sanitize_address address
+        unless recovery_id.nil?
+          # recover sender address
+          v = Chain.to_v recovery_id, chain_id
+          public_key = Signature.recover(unsigned_hash, "#{r.rjust(64, "0")}#{s.rjust(64, "0")}#{v.to_s(16)}", chain_id)
+          address = Util.public_key_to_address(public_key).to_s
+          @sender = Tx.sanitize_address address
+        else
+          # keep the 'from' field blank
+          @sender = Tx.sanitize_address nil
+        end
       end
 
       # Creates an unsigned copy of a transaction payload.

lib/eth/tx/eip2930.rb

@@ -181,11 +181,16 @@ def decode(hex)
         # last but not least, set the type.
         @type = TYPE_2930
 
-        # recover sender address
-        v = Chain.to_v recovery_id, chain_id
-        public_key = Signature.recover(unsigned_hash, "#{r.rjust(64, "0")}#{s.rjust(64, "0")}#{v.to_s(16)}", chain_id)
-        address = Util.public_key_to_address(public_key).to_s
-        @sender = Tx.sanitize_address address
+        unless recovery_id.nil?
+          # recover sender address
+          v = Chain.to_v recovery_id, chain_id
+          public_key = Signature.recover(unsigned_hash, "#{r.rjust(64, "0")}#{s.rjust(64, "0")}#{v.to_s(16)}", chain_id)
+          address = Util.public_key_to_address(public_key).to_s
+          @sender = Tx.sanitize_address address
+        else
+          # keep the 'from' field blank
+          @sender = Tx.sanitize_address nil
+        end
       end
 
       # Creates an unsigned copy of a transaction payload.

lib/eth/tx/legacy.rb

@@ -154,13 +154,11 @@ def decode(hex)
         _set_signature(v, r, s)
 
         unless chain_id.nil?
-
           # recover sender address
           public_key = Signature.recover(unsigned_hash, "#{r.rjust(64, "0")}#{s.rjust(64, "0")}#{v}", chain_id)
           address = Util.public_key_to_address(public_key).to_s
           @sender = Tx.sanitize_address address
         else
-
           # keep the 'from' field blank
           @sender = Tx.sanitize_address nil
         end

spec/eth/tx_spec.rb

@@ -122,4 +122,32 @@
       expect(tx.chain_id).to eq 56
     end
   end
+
+  describe '.decode an unsigned transaction' do
+    context 'EIP-1559' do
+      it "keeps the 'from' field blank" do
+        raw = "0x02f0050584b2d05e00851010b872008303841494caedbd63fb25c3126bfe96c1af208e4688e9817e87f6a3d9c63df00080c0"
+        tx = Tx.decode raw
+
+        expect(tx.signature_y_parity).to eq nil
+        expect(tx.signature_r).to eq 0
+        expect(tx.signature_s).to eq 0
+
+        expect(tx.sender).to eq ""
+      end
+    end
+
+    context 'EIP-2930' do
+      it "keeps the 'from' field blank" do
+        raw = "01eb050585037e11d6008303841494caedbd63fb25c3126bfe96c1af208e4688e9817e87f6a3d9c63df00080c0"
+        tx = Tx.decode raw
+
+        expect(tx.signature_y_parity).to eq nil
+        expect(tx.signature_r).to eq 0
+        expect(tx.signature_s).to eq 0
+
+        expect(tx.sender).to eq ""
+      end
+    end
+  end
 end