fix: readValue UInt256 error (#224)

* fix: readValue UInt256 error

Fixing `readValue(reader`gensym50, result)' is of type 'UInt256' and has
to be used (or discarded)` error by ensuring value returned by
`readValue` is used.

* Only one readValue function needs to be defined

* ci: force arm64 target

For some reason, clang assumed x86_64 and rejected nimcrypto's
"-march=armv8-a+crypto" flag.

Author: fryorcraken

.github/workflows/ci.yml

@@ -148,6 +148,12 @@ jobs:
           echo "ncpu=$ncpu" >> $GITHUB_ENV
           echo "MAKE_CMD=${MAKE_CMD}" >> $GITHUB_ENV
 
+      - name: Configure ARM64 build environment (macOS)
+        if: runner.os == 'macOS' && matrix.target.cpu == 'arm64'
+        run: |
+          # Force ARM64 architecture for Nim compilation with proper flags passed to clang
+          echo "NIMFLAGS=--cpu:arm64 --cc:clang --passC:\"-target arm64-apple-macos11\" --passL:\"-target arm64-apple-macos11\"" >> $GITHUB_ENV                                                                                            
+
       - name: Build Nim and Nimble
         run: |
           curl -O -L -s -S https://raw.githubusercontent.com/status-im/nimbus-build-system/master/scripts/build_nim.sh

web3/decoding.nim

@@ -325,24 +325,16 @@ proc decode*(decoder: var AbiDecoder, T: type): T {.raises: [SerializationError]
     decoder.finish()
     return value
 
-proc readValue*[T](r: var AbiReader, value: T): T {.raises: [SerializationError]} =
-  try:
-    readValue[T](r, T)
-  except SerializationError as e:
-    raise newException(SerializationError, e.msg)
-
-proc readValue*[T](r: var AbiReader, _: typedesc[T]): T {.raises: [SerializationError]} =
-  var resultObj: T
+proc readValue*[T](r: var AbiReader, value: var T) {.raises: [SerializationError]} =
   var decoder = AbiDecoder(input: r.getStream)
   type StInts = StInt | StUint
 
   when T is object and T is not StInts:
-    resultObj = decodeObject(decoder, T)
+    value = decodeObject(decoder, T)
   else:
-    resultObj = decoder.decode(T)
+    value = decoder.decode(T)
 
   decoder.finish()
-  result = resultObj
 
 # Keep the old encode functions for compatibility
 func decode*(input: openArray[byte], baseOffset, offset: int, to: var StUint): int {.deprecated: "use Abi.decode instead"} =