Prevent possible F#4.0 issue

It seems that these attributes can cause this compilation error in F#4.0:
error FS0927: The kind of the type specified by its attributes does not match the kind implied by its definition

Newer versions of F# (like 4.5 or even newer, like the one being used
by .NETCore to build the binary that is later published in nuget) allow
compiling this code with no issues, but if you reference the generated
assembly later from an old F# compiler, it could generate exceptions at
runtime, e.g.: System.BadFormatImageException (or other types) whose
inner exception could be the following:

System.TypeLoadException : Could not load type of field 'GWallet.Backend.UtxoCoin.Lightning.SerializedChannel:MinSafeDepth@' (6) due to: Expected reference type but got type kind 17

FSharp.Core's Result type is also affected by this so in this commit we
create a replacement for it that is only used in the BouncyCastle build
(which we now rename as 'Portability' build).

Forward-ported from a4a59d0

Co-authored-by: Andres G. Aragoneses <knocte@gmail.com>

Author: Bobface

.github/workflows/ci.yml

@@ -15,11 +15,11 @@ jobs:
       with:
         dotnet-version: ${{ matrix.dotnet }}
 
-    - name: Run tests (BouncyCastle)
+    - name: Run tests (Portability)
       # we want to run only once.
       if: startsWith(matrix.os, 'ubuntu-18')
       run: |
-        dotnet build tests/DotNetLightning.Core.Tests -p:BouncyCastle=True
+        dotnet build tests/DotNetLightning.Core.Tests -p:Portability=True
         dotnet run --no-build --project tests/DotNetLightning.Core.Tests
 
     - name: Clean to prepare for NSec build
@@ -40,6 +40,6 @@ jobs:
       run: |
         DEBIAN_FRONTEND=noninteractive sudo apt install -y msbuild fsharp
 
-        dotnet restore -p:BouncyCastle=True DotNetLightning.sln
-        msbuild src/DotNetLightning.Core/DotNetLightning.Core.fsproj -p:BouncyCastle=True -p:TargetFramework=netstandard2.0
+        dotnet restore -p:Portability=True DotNetLightning.sln
+        msbuild src/DotNetLightning.Core/DotNetLightning.Core.fsproj -p:Portability=True -p:TargetFramework=netstandard2.0
 

.github/workflows/publish_master.yml

@@ -29,8 +29,8 @@ jobs:
       with:
         dotnet-version: '3.1.200'
 
-    - name: Upload nuget packages (BouncyCastle)
+    - name: Upload nuget packages (Portability)
       if: startsWith(matrix.os, 'ubuntu')
       run: |
-        dotnet pack ./src/DotNetLightning.Core -p:Configuration=Release --version-suffix date`date +%Y%m%d-%H%M`-git-`echo $GITHUB_SHA | head -c 7` -p:BouncyCastle=True
+        dotnet pack ./src/DotNetLightning.Core -p:Configuration=Release --version-suffix date`date +%Y%m%d-%H%M`-git-`echo $GITHUB_SHA | head -c 7` -p:Portability=True
         dotnet nuget push ./src/DotNetLightning.Core/bin/Release/DotNetLightning.Kiss.1*.nupkg -k ${{ secrets.NUGET_API_KEY }} -s https://api.nuget.org/v3/index.json

Directory.Build.props

@@ -8,22 +8,22 @@
 
   <!-->Since NBitcoin.Secp256k1 does not support netstandard 2.0, we will fallback to BouncyCastle build<-->
   <PropertyGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
-    <BouncyCastle>True</BouncyCastle>
+    <Portability>True</Portability>
   </PropertyGroup>
 
 
   <Choose>
-    <When Condition="'$(BouncyCastle)'=='true'">
+    <When Condition="'$(Portability)'=='true'">
       <PropertyGroup>
-        <OtherFlags>$(OtherFlags) -d:BouncyCastle</OtherFlags>
-        <DefineConstants>$(DefineConstants);BouncyCastle</DefineConstants>
+        <OtherFlags>$(OtherFlags) -d:NoDUsAsStructs -d:BouncyCastle</OtherFlags>
+        <DefineConstants>$(DefineConstants);NoDUsAsStructs;BouncyCastle</DefineConstants>
       </PropertyGroup>
     </When>
   </Choose>
 
   <ItemGroup>
     <PackageReference Include="NBitcoin" Version="5.0.65" />
-    <PackageReference Condition="'$(BouncyCastle)'=='true'" Include="Portable.BouncyCastle" Version="1.8.6.7" />
+    <PackageReference Condition="'$(Portability)'=='true'" Include="Portable.BouncyCastle" Version="1.8.6.7" />
   </ItemGroup>
 
   <PropertyGroup>

src/DotNetLightning.Core/Channel/Channel.fs

@@ -1,7 +1,5 @@
 namespace DotNetLightning.Channel
 
-open ResultUtils
-
 open DotNetLightning.Utils
 open DotNetLightning.Utils.NBitcoinExtensions
 open DotNetLightning.Utils.Aether
@@ -12,6 +10,8 @@ open DotNetLightning.Serialization.Msgs
 open NBitcoin
 open System
 
+open ResultUtils
+open ResultUtils.Portability
 
 type ProvideFundingTx = IDestination * Money * FeeRatePerKw -> Result<FinalizedTx * TxOutIndex, string> 
 type Channel = {

src/DotNetLightning.Core/Channel/ChannelError.fs

@@ -1,6 +1,5 @@
 namespace DotNetLightning.Channel
 
-open ResultUtils
 open DotNetLightning.Utils
 open NBitcoinExtensions
 open DotNetLightning.Utils.OnionError
@@ -11,6 +10,9 @@ open DotNetLightning.Transactions
 
 open NBitcoin
 
+open ResultUtils
+open ResultUtils.Portability
+
 type ChannelError =
     | CryptoError of CryptoError
     | TransactionRelatedErrors of TransactionError list

src/DotNetLightning.Core/Channel/ChannelOperations.fs

@@ -1,6 +1,5 @@
 namespace DotNetLightning.Channel
 
-open ResultUtils
 open DotNetLightning.Utils
 open DotNetLightning.Utils.NBitcoinExtensions
 open DotNetLightning.Utils.OnionError
@@ -13,6 +12,9 @@ open DotNetLightning.Serialization
 
 open NBitcoin
 
+open ResultUtils
+open ResultUtils.Portability
+
 type OperationMonoHopUnidirectionalPayment = {
     Amount: LNMoney
 }

src/DotNetLightning.Core/Channel/ChannelValidation.fs

@@ -1,6 +1,5 @@
 namespace DotNetLightning.Channel
 
-open ResultUtils
 open NBitcoin
 
 open DotNetLightning.Chain
@@ -10,6 +9,9 @@ open DotNetLightning.Utils.NBitcoinExtensions
 open DotNetLightning.Serialization.Msgs
 open DotNetLightning.Transactions
 
+open ResultUtils
+open ResultUtils.Portability
+
 exception ChannelException of ChannelError
 module internal ChannelHelpers =
 

src/DotNetLightning.Core/Channel/CommitmentToLocalExtension.fs

@@ -6,6 +6,9 @@ open DotNetLightning.Utils
 open DotNetLightning.Utils.SeqConsumer
 open DotNetLightning.Crypto
 
+open ResultUtils
+open ResultUtils.Portability
+
 type CommitmentToLocalParameters = {
     RevocationPubKey: RevocationPubKey
     ToSelfDelay: BlockHeightOffset16

src/DotNetLightning.Core/Channel/Commitments.fs

@@ -8,6 +8,9 @@ open DotNetLightning.Crypto
 open DotNetLightning.Transactions
 open DotNetLightning.Serialization.Msgs
 
+open ResultUtils
+open ResultUtils.Portability
+
 type LocalChanges = {
     Proposed: IUpdateMsg list
     Signed: IUpdateMsg list

src/DotNetLightning.Core/Channel/CommitmentsModule.fs

@@ -2,14 +2,15 @@ namespace DotNetLightning.Channel
 
 open NBitcoin
 
-open ResultUtils
-
 open DotNetLightning.Utils
 open DotNetLightning.Transactions
 open DotNetLightning.Crypto
 open DotNetLightning.Chain
 open DotNetLightning.Serialization.Msgs
 
+open ResultUtils
+open ResultUtils.Portability
+
 [<RequireQualifiedAccess; CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix)>]
 module internal Commitments =
     module private Helpers =