problem: invalid height matcher when block hash is specified

src/main/kotlin/io/emeraldpay/dshackle/upstream/calls/EthereumCallSelector.kt

@@ -73,34 +73,20 @@ class EthereumCallSelector(
             // for earliest it doesn't nothing, we expect to have 0 block
             "earliest" -> 0L
             else -> if (tag.startsWith("0x")) {
-                try {
-                    HexQuantity.from(tag).value.toLong()
-                } catch (t: Throwable) {
-                    log.debug("Invalid tag: $tag. ${t.javaClass}: ${t.message}")
-                    null
+                return if (tag.length == 66) { //32-byte hash is represented as 0x + 64 characters
+                    blockByHash(tag, head)
+                } else {
+                    blockByHeight(tag)
                 }
             } else if (tag.startsWith("{") && list[pos] is Map<*, *>) {
                 // see https://eips.ethereum.org/EIPS/eip-1898
                 val obj = list[pos] as Map<*, *>
                 when {
                     obj.containsKey("blockNumber") -> {
-                        try {
-                            HexQuantity.from(obj["blockNumber"].toString()).value.toLong()
-                        } catch (t: Throwable) {
-                            log.warn("Invalid blockNumber: $tag")
-                            null
-                        }
+                        return blockByHeight(obj["blockNumber"].toString())
                     }
                     obj.containsKey("blockHash") -> {
-                        try {
-                            val blockId = BlockId.from(obj["blockHash"].toString())
-                            return heightReader.read(blockId)
-                                    .switchIfEmpty(Mono.justOrEmpty(head.getCurrentHeight()))
-                                    .map { Selector.HeightMatcher(it) }
-                        } catch (t: Throwable) {
-                            log.warn("Invalid blockHash: $tag")
-                            null
-                        }
+                        return blockByHash(obj["blockHash"].toString(), head)
                     }
                     else -> null
                 }
@@ -116,4 +102,25 @@ class EthereumCallSelector(
         }
     }
 
+    private fun blockByHeight(blockNumber: String): Mono<Selector.Matcher> {
+        return try {
+            Mono.just(Selector.HeightMatcher(HexQuantity.from(blockNumber).value.longValueExact()))
+        } catch (t: Throwable) {
+            log.warn("Invalid blockNumber: $blockNumber")
+            Mono.empty<Selector.Matcher>()
+        }
+    }
+
+    private fun blockByHash(blockHash: String, head: Head): Mono<Selector.Matcher> {
+        return try {
+            val blockId = BlockId.from(blockHash)
+            heightReader.read(blockId)
+                    .switchIfEmpty(Mono.justOrEmpty(head.getCurrentHeight()))
+                    .map { Selector.HeightMatcher(it) }
+        } catch (t: Throwable) {
+            log.warn("Invalid blockHash: $blockHash")
+            Mono.empty<Selector.Matcher>()
+        }
+    }
+
 }

src/test/groovy/io/emeraldpay/dshackle/upstream/calls/EthereumCallSelectorSpec.groovy

@@ -73,6 +73,59 @@ class EthereumCallSelectorSpec extends Specification {
         act == new Selector.HeightMatcher(0x40)
     }
 
+    def "Get height matcher for balance on block referred by hash"() {
+        setup:
+        def heights = Mock(Reader) {
+            1 * it.read(BlockId.from("0xc90f1c8c125a4d5b90742f16947bdb1d10516f173fd7fc51223d10499de2a812")) >> Mono.just(8606722L)
+        }
+        EthereumCallSelector callSelector = new EthereumCallSelector(heights)
+        def head = Mock(Head) {
+            _ * getCurrentHeight() >> 9128116
+        }
+        when:
+        def act = callSelector.getMatcher("eth_getBalance", '["0x0000", "0xc90f1c8c125a4d5b90742f16947bdb1d10516f173fd7fc51223d10499de2a812"]', head).block()
+        then:
+        act == new Selector.HeightMatcher(8606722)
+    }
+
+    def "No matcher for invalid height"() {
+        setup:
+        EthereumCallSelector callSelector = new EthereumCallSelector(Stub(Reader))
+        def head = Mock(Head) {
+            _ * getCurrentHeight() >> 100
+        }
+        when:
+        // 0x10000000000000000 is too large to be a block
+        def act = callSelector.getMatcher("eth_getBalance", '["0x0000", "0x10000000000000000"]', head).block()
+        then:
+        act == null
+    }
+
+    def "No matcher for negative height"() {
+        setup:
+        EthereumCallSelector callSelector = new EthereumCallSelector(Stub(Reader))
+        def head = Mock(Head) {
+            _ * getCurrentHeight() >> 100
+        }
+        when:
+        def act = callSelector.getMatcher("eth_getBalance", '["0x0000", "-0x100"]', head).block()
+        then:
+        act == null
+    }
+
+    def "No matcher for negative long"() {
+        setup:
+        EthereumCallSelector callSelector = new EthereumCallSelector(Stub(Reader))
+        def head = Mock(Head) {
+            _ * getCurrentHeight() >> 100
+        }
+        when:
+        // 0x8000000000000000 becomes -9223372036854775808 in converted to long as is, i.e. high bit is set
+        def act = callSelector.getMatcher("eth_getBalance", '["0x0000", "0x8000000000000000"]', head).block()
+        then:
+        act == null
+    }
+
     def "No matcher for pending balance"() {
         setup:
         EthereumCallSelector callSelector = new EthereumCallSelector(Stub(Reader))