parser: replace genesis "blockheight" with zero

parser/block.go

@@ -52,6 +52,9 @@ func (b *block) HasSaplingTransactions() bool {
 	return false
 }
 
+// see https://github.com/zcash-hackworks/lightwalletd/issues/17#issuecomment-467110828
+const genesisTargetDifficulty = 520617983
+
 // GetHeight() extracts the block height from the coinbase transaction. See
 // BIP34. Returns block height on success, or -1 on error.
 func (b *block) GetHeight() int {
@@ -74,6 +77,11 @@ func (b *block) GetHeight() int {
 		blockHeight <<= 8
 		blockHeight = blockHeight | uint32(heightBytes[i])
 	}
+
+	if blockHeight == genesisTargetDifficulty {
+		blockHeight = 0
+	}
+
 	b.height = int(blockHeight)
 	return int(blockHeight)
 }

parser/block_test.go

@@ -42,6 +42,46 @@ func TestBlockParser(t *testing.T) {
 			t.Error("Read wrong version in a test block.")
 			break
 		}
+
+		if block.GetTxCount() < 1 {
+			t.Error("No transactions in block")
+			break
+		}
+	}
+}
+
+func TestGenesisBlockParser(t *testing.T) {
+	blockFile, err := os.Open("../testdata/mainnet_genesis")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer blockFile.Close()
+
+	scan := bufio.NewScanner(blockFile)
+	for i := 0; scan.Scan(); i++ {
+		blockDataHex := scan.Text()
+		blockData, err := hex.DecodeString(blockDataHex)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		block := NewBlock()
+		blockData, err = block.ParseFromSlice(blockData)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		// Some basic sanity checks
+		if block.hdr.Version != 4 {
+			t.Error("Read wrong version in genesis block.")
+			break
+		}
+
+		if block.GetHeight() != 0 {
+			t.Errorf("Got wrong height for genesis block: %d", block.GetHeight())
+		}
 	}
 }
 

testdata/mainnet_genesis

@@ -0,0 +1 @@
+040000000000000000000000000000000000000000000000000000000000000000000000db4d7a85b768123f1dff1d4c4cece70083b2d27e117b4ac2e31d087988a5eac4000000000000000000000000000000000000000000000000000000000000000090041358ffff071f5712000000000000000000000000000000000000000000000000000000000000fd4005000a889f00854b8665cd555f4656f68179d31ccadc1b1f7fb0952726313b16941da348284d67add4686121d4e3d930160c1348d8191c25f12b267a6a9c131b5031cbf8af1f79c9d513076a216ec87ed045fa966e01214ed83ca02dc1797270a454720d3206ac7d931a0a680c5c5e099057592570ca9bdf6058343958b31901fce1a15a4f38fd347750912e14004c73dfe588b903b6c03166582eeaf30529b14072a7b3079e3a684601b9b3024054201f7440b0ee9eb1a7120ff43f713735494aa27b1f8bab60d7f398bca14f6abb2adbf29b04099121438a7974b078a11635b594e9170f1086140b4173822dd697894483e1c6b4e8b8dcd5cb12ca4903bc61e108871d4d915a9093c18ac9b02b6716ce1013ca2c1174e319c1a570215bc9ab5f7564765f7be20524dc3fdf8aa356fd94d445e05ab165ad8bb4a0db096c097618c81098f91443c719416d39837af6de85015dca0de89462b1d8386758b2cf8a99e00953b308032ae44c35e05eb71842922eb69797f68813b59caf266cb6c213569ae3280505421a7e3a0a37fdf8e2ea354fc5422816655394a9454bac542a9298f176e211020d63dee6852c40de02267e2fc9d5e1ff2ad9309506f02a1a71a0501b16d0d36f70cdfd8de78116c0c506ee0b8ddfdeb561acadf31746b5a9dd32c21930884397fb1682164cb565cc14e089d66635a32618f7eb05fe05082b8a3fae620571660a6b89886eac53dec109d7cbb6930ca698a168f301a950be152da1be2b9e07516995e20baceebecb5579d7cdbc16d09f3a50cb3c7dffe33f26686d4ff3f8946ee6475e98cf7b3cf9062b6966e838f865ff3de5fb064a37a21da7bb8dfd2501a29e184f207caaba364f36f2329a77515dcb710e29ffbf73e2bbd773fab1f9a6b005567affff605c132e4e4dd69f36bd201005458cfbd2c658701eb2a700251cefd886b1e674ae816d3f719bac64be649c172ba27a4fd55947d95d53ba4cbc73de97b8af5ed4840b659370c556e7376457f51e5ebb66018849923db82c1c9a819f173cccdb8f3324b239609a300018d0fb094adf5bd7cbb3834c69e6d0b3798065c525b20f040e965e1a161af78ff7561cd874f5f1b75aa0bc77f720589e1b810f831eac5073e6dd46d00a2793f70f7427f0f798f2f53a67e615e65d356e66fe40609a958a05edb4c175bcc383ea0530e67ddbe479a898943c6e3074c6fcc252d6014de3a3d292b03f0d88d312fe221be7be7e3c59d07fa0f2f4029e364f1f355c5d01fa53770d0cd76d82bf7e60f6903bc1beb772e6fde4a70be51d9c7e03c8d6d8dfb361a234ba47c470fe630820bbd920715621b9fbedb49fcee165ead0875e6c2b1af16f50b5d6140cc981122fcbcf7c5a4e3772b3661b628e08380abc545957e59f634705b1bbde2f0b4e055a5ec5676d859be77e20962b645e051a880fddb0180b4555789e1f9344a436a84dc5579e2553f1e5fb0a599c137be36cabbed0319831fea3fddf94ddc7971e4bcf02cdc93294a9aab3e3b13e3b058235b4f4ec06ba4ceaa49d675b4ba80716f3bc6976b1fbf9c8bf1f3e3a4dc1cd83ef9cf816667fb94f1e923ff63fef072e6a19321e4812f96cb0ffa864da50ad74deb76917a336f31dce03ed5f0303aad5e6a83634f9fcc371096f8288b8f02ddded5ff1bb9d49331e4a84dbe1543164438fde9ad71dab024779dcdde0b6602b5ae0a6265c14b94edd83b37403f4b78fcd2ed555b596402c28ee81d87a909c4e8722b30c71ecdd861b05f61f8b1231795c76adba2fdefa451b283a5d527955b9f3de1b9828e7b2e74123dd47062ddcc09b05e7fa13cb2212a6fdbc65d7e852cec463ec6fd929f5b8483cf3052113b13dac91b69f49d1b7d1aec01c4a68e41ce1570101000000010000000000000000000000000000000000000000000000000000000000000000ffffffff4d04ffff071f0104455a6361736830623963346565663862376363343137656535303031653335303039383462366665613335363833613763616331343161303433633432303634383335643334ffffffff010000000000000000434104678afdb0fe5548271967f1a67130b7105cd6a828e03909a67962e0ea1f61deb649f6bc3f4cef38c4f35504e51ec112de5c384df7ba0b8d578a4c702b6bf11d5fac00000000