Backend(,Tests): stop using binary serialization

We had a need in the past to serialize exceptions (as they could
happen in off-line mode, when running as a cold-storage device),
so that they could be reported later when the device comes
online, but exceptions can't be seralizated to JSON (as
explained in [1]), so we ended up using binary serialization
(hooking it up in this past commit[2]).

However, binary serialization is going away in .NET9[3] because
of its potential security risk. Even though we doubt that for
our use case we would be affected by this security vector, we:

- Want to be prepared for the future.
- Know that there were anyway edge cases where binary
serialization was not actually working (e.g. see bug 240), and
was causing crashes.

We explored the idea of contributing an IException interface to
the 'sentry-dotnet' repo [4] (this library is the replacement of
SharpRaven, see [5]), so that we can serialize exceptions easily
in JSON, for later deserializing them and send them straight to
Sentry's API for report purposes, however:

* We found adding the IException overloads to be extremely
complicated due to the sheer amount of unit tests and things
that Sentry has, that would need to be modified.
* Given the above, we thought it would be too much work, and too
much risk of not being accepted upstream.
* Even if the IException overloads were accepted, the approach
would still be a leaky abstraction because the type of the
exception cannot be properly represented in a hypothetical
IException's property, so we were/would ending up with hacky
things such as an IsAggregateException:bool property, for
example. But why end here and not have more bool types for
other exceptions?

Instead of the above nightmare we have decided to go for the
simplest approach of all (the one that I should have done 3ish
years ago when I was initially solving this problem, to avoid
any OVERENGINEERING): just use good old Exception.ToString()
method! This method provides, not only the type of the
exception and its .Message property, also all its inner
exceptions recursively. This is GOOD ENOUGH.

Fixes #240
Closes https://gitlab.com/nblockchain/geewallet/-/issues/174

[1] 403d5c7
[2] 1f7b3b7
[3] https://twitter.com/SitnikAdam/status/1746874459640811575
[4] https://github.com/getsentry/sentry-dotnet
[5] #252

src/GWallet.Backend.Tests/ExceptionMarshalling.fs

@@ -8,7 +8,7 @@ open NUnit.Framework
 open GWallet.Backend
 
 
-type CustomExceptionWithoutSerializationCtor =
+type CustomExceptionWithoutInnerExceptionCtor =
    inherit Exception
 
    new(message) =
@@ -17,8 +17,6 @@ type CustomExceptionWithoutSerializationCtor =
 type CustomException =
    inherit Exception
 
-   new(info: SerializationInfo, context: StreamingContext) =
-       { inherit Exception(info, context) }
    new(message: string, innerException: CustomException) =
        { inherit Exception(message, innerException) }
    new(message) =
@@ -78,7 +76,7 @@ type ExceptionMarshalling () =
         let json = SerializeBasicException ()
         Assert.That(json, Is.Not.Null)
         Assert.That(json, Is.Not.Empty)
-        Assert.That(MarshallingData.SerializedExceptionsAreSame json MarshallingData.BasicExceptionExampleInJson false msg)
+        Assert.That(MarshallingData.SerializedExceptionsAreSame json MarshallingData.BasicExceptionExampleInJson msg)
 
     [<Test>]
     member __.``can deserialize basic exceptions``() =
@@ -102,20 +100,7 @@ type ExceptionMarshalling () =
         let json = SerializeRealException ()
         Assert.That(json, Is.Not.Null)
         Assert.That(json, Is.Not.Empty)
-#if !LEGACY_FRAMEWORK
-        Assert.That(MarshallingData.SerializedExceptionsAreSame json MarshallingData.RealExceptionExampleInJson false msg)
-#else
-        if Config.IsWindowsPlatform () then
-            let serializedExceptionsAreSame =
-                try
-                    MarshallingData.SerializedExceptionsAreSame json MarshallingData.RealExceptionExampleInJson false msg
-                with
-                | :? AssertionException ->
-                    MarshallingData.SerializedExceptionsAreSame json MarshallingData.RealExceptionWindowsLegacyExampleInJson false legacyMsg
-            Assert.That serializedExceptionsAreSame
-        else
-            Assert.That(MarshallingData.SerializedExceptionsAreSame json MarshallingData.RealExceptionUnixLegacyExampleInJson false legacyMsg)
-#endif
+        Assert.That(MarshallingData.SerializedExceptionsAreSame json MarshallingData.RealExceptionExampleInJson msg)
 
     [<Test>]
     member __.``can deserialize real exceptions``() =
@@ -140,7 +125,7 @@ type ExceptionMarshalling () =
         let json = SerializeInnerException ()
         Assert.That(json, Is.Not.Null)
         Assert.That(json, Is.Not.Empty)
-        Assert.That(MarshallingData.SerializedExceptionsAreSame json MarshallingData.InnerExceptionExampleInJson false msg)
+        Assert.That(MarshallingData.SerializedExceptionsAreSame json MarshallingData.InnerExceptionExampleInJson msg)
 
     [<Test>]
     member __.``can deserialize inner exceptions``() =
@@ -168,15 +153,15 @@ type ExceptionMarshalling () =
         let json = SerializeCustomException ()
         Assert.That(json, Is.Not.Null)
         Assert.That(json, Is.Not.Empty)
-        Assert.That(MarshallingData.SerializedExceptionsAreSame json MarshallingData.CustomExceptionExampleInJson false msg)
+        Assert.That(MarshallingData.SerializedExceptionsAreSame json MarshallingData.CustomExceptionExampleInJson msg)
 
     [<Test>]
     member __.``serializing custom exception not prepared for binary serialization, throws``() =
-        let exToSerialize = CustomExceptionWithoutSerializationCtor "msg"
+        let exToSerialize = CustomExceptionWithoutInnerExceptionCtor "msg"
         let ex: MarshallingCompatibilityException =
             Assert.Throws(fun _ -> Marshalling.Serialize exToSerialize |> ignore<string>)
         Assert.That(ex, Is.TypeOf<MarshallingCompatibilityException>())
-        Assert.That(ex.Message, IsString.WhichContains "GWallet.Backend.Tests.CustomExceptionWithoutSerializationCtor")
+        Assert.That(ex.Message, IsString.WhichContains "GWallet.Backend.Tests.CustomExceptionWithoutInnerExceptionCtor")
 
     [<Test>]
     member __.``can deserialize custom exceptions``() =
@@ -200,9 +185,7 @@ type ExceptionMarshalling () =
         let json = SerializeCustomFSharpException ()
         Assert.That(json, Is.Not.Null)
         Assert.That(json, Is.Not.Empty)
-
-        // strangely enough, message would be different between linux_vanilla_dotnet6 and other dotnet6 configs (e.g. Windows, macOS, Linux-github)
-        Assert.That(MarshallingData.SerializedExceptionsAreSame json MarshallingData.CustomFSharpExceptionExampleInJson true msg)
+        Assert.That(MarshallingData.SerializedExceptionsAreSame json MarshallingData.CustomFSharpExceptionExampleInJson msg)
 
     [<Test>]
     member __.``can deserialize F# custom exceptions``() =
@@ -230,21 +213,7 @@ type ExceptionMarshalling () =
 
         Assert.That(json, Is.Not.Null)
         Assert.That(json, Is.Not.Empty)
-
-#if !LEGACY_FRAMEWORK
-        Assert.That(MarshallingData.SerializedExceptionsAreSame json MarshallingData.FullExceptionExampleInJson false msg)
-#else
-        if Config.IsWindowsPlatform () then
-            let serializedExceptionsAreSame =
-                try
-                    MarshallingData.SerializedExceptionsAreSame json MarshallingData.FullExceptionExampleInJson false msg
-                with
-                | :? AssertionException ->
-                    MarshallingData.SerializedExceptionsAreSame json MarshallingData.FullExceptionWindowsLegacyExampleInJson false legacyMsg
-            Assert.That serializedExceptionsAreSame
-        else
-            Assert.That(MarshallingData.SerializedExceptionsAreSame json MarshallingData.FullExceptionUnixLegacyExampleInJson false legacyMsg)
-#endif
+        Assert.That(MarshallingData.SerializedExceptionsAreSame json MarshallingData.FullExceptionExampleInJson msg)
 
     [<Test>]
     member __.``can deserialize full exceptions (all previous features combined)``() =

src/GWallet.Backend.Tests/GWallet.Backend.Tests.fsproj

@@ -39,18 +39,13 @@
   <ItemGroup>
     <EmbeddedResource Include="data\basicException.json" />
     <EmbeddedResource Include="data\customFSharpException.json" />
-    <EmbeddedResource Include="data\customFSharpException_legacy.json" />
     <EmbeddedResource Include="data\realException.json" />
-    <EmbeddedResource Include="data\realException_unixLegacy.json" />
-    <EmbeddedResource Include="data\realException_windowsLegacy.json" />
     <EmbeddedResource Include="data\signedAndFormattedEtherTransaction.json" />
     <EmbeddedResource Include="data\customException.json" />
     <EmbeddedResource Include="data\unsignedAndFormattedSaiTransaction.json" />
     <EmbeddedResource Include="data\unsignedAndFormattedBtcTransaction.json" />
     <EmbeddedResource Include="data\unsignedAndFormattedEtherTransaction.json" />
     <EmbeddedResource Include="data\fullException.json" />
-    <EmbeddedResource Include="data\fullException_unixLegacy.json" />
-    <EmbeddedResource Include="data\fullException_windowsLegacy.json" />
     <EmbeddedResource Include="data\signedAndFormattedBtcTransaction.json" />
     <EmbeddedResource Include="data\signedAndFormattedSaiTransaction.json" />
     <EmbeddedResource Include="data\innerException.json" />

src/GWallet.Backend.Tests/MarshallingData.fs

@@ -16,7 +16,7 @@ module MarshallingData =
     let private executingAssembly = Assembly.GetExecutingAssembly()
     let private version = VersionHelper.CURRENT_VERSION
     let private binPath = executingAssembly.Location |> FileInfo
-    let private prjPath = Path.Combine(binPath.Directory.FullName, "..") |> DirectoryInfo
+    let private prjPath = Path.Combine(binPath.Directory.FullName, "..", "..", "..") |> DirectoryInfo
 
     let private RemoveJsonFormatting (jsonContent: string): string =
         jsonContent.Replace("\r", String.Empty)
@@ -50,12 +50,6 @@ module MarshallingData =
     let RealExceptionExampleInJson =
         ReadEmbeddedResource "realException.json"
 
-    let RealExceptionUnixLegacyExampleInJson =
-        ReadEmbeddedResource "realException_unixLegacy.json"
-
-    let RealExceptionWindowsLegacyExampleInJson =
-        ReadEmbeddedResource "realException_windowsLegacy.json"
-
     let InnerExceptionExampleInJson =
         ReadEmbeddedResource "innerException.json"
 
@@ -65,80 +59,35 @@ module MarshallingData =
     let CustomFSharpExceptionExampleInJson =
         ReadEmbeddedResource "customFSharpException.json"
 
-    let CustomFSharpExceptionLegacyExampleInJson =
-        ReadEmbeddedResource "customFSharpException_legacy.json"
-
     let FullExceptionExampleInJson =
         ReadEmbeddedResource "fullException.json"
 
-    let FullExceptionUnixLegacyExampleInJson =
-        ReadEmbeddedResource "fullException_unixLegacy.json"
-
-    let FullExceptionWindowsLegacyExampleInJson =
-        ReadEmbeddedResource "fullException_windowsLegacy.json"
-
     let rec TrimOutsideAndInside(str: string) =
         let trimmed = str.Replace("  ", " ").Trim()
         if trimmed = str then
             trimmed
         else
             TrimOutsideAndInside trimmed
 
-    let SerializedExceptionsAreSame actualJsonString expectedJsonString ignoreExMessage msg =
-
-        let actualJsonException = JObject.Parse actualJsonString
-        let expectedJsonException = JObject.Parse expectedJsonString
-
-        let fullBinaryFormPath = "Value.FullBinaryForm"
-        let tweakStackTraces () =
-
-            let fullBinaryFormBeginning = "AAEAAAD/////AQAA"
-            let stackTracePath = "Value.HumanReadableSummary.StackTrace"
-            let stackTraceFragment = "ExceptionMarshalling.fs"
-
-            let tweakStackTraceAndBinaryForm (jsonEx: JObject) (assertBinaryForm: bool) =
-                let stackTraceJToken = jsonEx.SelectToken stackTracePath
-                Assert.That(stackTraceJToken, Is.Not.Null, sprintf "Path %s not found in %s" stackTracePath (jsonEx.ToString()))
-                let initialStackTraceJToken = stackTraceJToken.ToString()
-                if initialStackTraceJToken.Length > 0 then
-                    Assert.That(initialStackTraceJToken, IsString.WhichContains stackTraceFragment,
-                                sprintf "comparing actual '%s' with expected '%s'" actualJsonString expectedJsonString)
-                    let endOfStackTrace = initialStackTraceJToken.Substring(initialStackTraceJToken.IndexOf stackTraceFragment)
-                    let tweakedEndOfStackTrace =
-                        endOfStackTrace
-                            .Replace(":line 42", ":41 ")
-                            .Replace(":line 41", ":41 ")
-                            .Replace(":line 65", ":64 ")
-                            .Replace(":line 64", ":64 ")
-                    stackTraceJToken.Replace (tweakedEndOfStackTrace |> JToken.op_Implicit)
-
-                let binaryFormToken = jsonEx.SelectToken fullBinaryFormPath
-                Assert.That(binaryFormToken, Is.Not.Null, sprintf "Path %s not found in %s" fullBinaryFormPath (jsonEx.ToString()))
-                let initialBinaryFormJToken = binaryFormToken.ToString()
-                if assertBinaryForm then
-                    Assert.That(initialBinaryFormJToken, IsString.StartingWith fullBinaryFormBeginning)
-                binaryFormToken.Replace (fullBinaryFormBeginning |> JToken.op_Implicit)
-
-            tweakStackTraceAndBinaryForm actualJsonException true
-            tweakStackTraceAndBinaryForm expectedJsonException false
-
-        tweakStackTraces()
-
-        // strangely enough, message would be different between linux_vanilla_dotnet6 and other dotnet6 configs (e.g. Windows, macOS, Linux-github)
-        if ignoreExMessage then
-            let exMessagePath = "Value.HumanReadableSummary.Message"
-            let actualMsgToken = actualJsonException.SelectToken exMessagePath
-            Assert.That(actualMsgToken, Is.Not.Null, sprintf "Path %s not found in %s" exMessagePath (actualJsonException.ToString()))
-            let expectedMsgToken = expectedJsonException.SelectToken exMessagePath
-            Assert.That(expectedMsgToken, Is.Not.Null, sprintf "Path %s not found in %s" exMessagePath (expectedJsonException.ToString()))
-            actualMsgToken.Replace(String.Empty |> JToken.op_Implicit)
-            expectedMsgToken.Replace(String.Empty |> JToken.op_Implicit)
-
-        let actualBinaryForm = (actualJsonException.SelectToken fullBinaryFormPath).ToString()
+    let SerializedExceptionsAreSame actualJsonString expectedJsonString (msg: string) =
+        let actualJson = JObject.Parse actualJsonString
+        Assert.That(actualJson, Is.Not.Null)
+        let expectedJson = JObject.Parse expectedJsonString
+        Assert.That(expectedJson, Is.Not.Null)
+
+        let fullDescPath = "Value.FullDescription"
+        let actualJsonToken = actualJson.SelectToken fullDescPath
+        Assert.That(actualJsonToken, Is.Not.Null)
+        let expectedJsonToken = expectedJson.SelectToken fullDescPath
+        Assert.That(expectedJsonToken, Is.Not.Null)
+
+        let actualFullDesc = actualJsonToken.ToString()
+        let expectedFullDesc = expectedJsonToken.ToString()
+
         Assert.That(
-            TrimOutsideAndInside(actualJsonException.ToString()),
-            Is.EqualTo (TrimOutsideAndInside(expectedJsonException.ToString())),
-            msg + actualBinaryForm
+            TrimOutsideAndInside actualFullDesc,
+            Is.EqualTo (TrimOutsideAndInside expectedFullDesc),
+            msg
         )
 
         true

src/GWallet.Backend.Tests/data/basicException.json

@@ -2,12 +2,7 @@
   "Version": "{version}",
   "TypeName": "GWallet.Backend.MarshalledException",
   "Value": {
-    "HumanReadableSummary": {
-      "ExceptionType": "System.Exception",
-      "Message": "msg",
-      "StackTrace": "",
-      "InnerException": null
-    },
-    "FullBinaryForm": "{binaryMarshalledException}"
+    "DateTimeUtc": "<this value is not compared in tests>",
+    "FullDescription": "System.Exception: msg"
   }
 }

src/GWallet.Backend.Tests/data/customException.json

@@ -2,12 +2,7 @@
   "Version": "{version}",
   "TypeName": "GWallet.Backend.MarshalledException",
   "Value": {
-    "HumanReadableSummary": {
-      "ExceptionType": "GWallet.Backend.Tests.CustomException",
-      "Message": "msg",
-      "StackTrace": "",
-      "InnerException": null
-    },
-    "FullBinaryForm": "{binaryMarshalledException}"
+    "DateTimeUtc": "<this value is not compared in tests>",
+    "FullDescription": "GWallet.Backend.Tests.CustomException: msg"
   }
 }

src/GWallet.Backend.Tests/data/customFSharpException.json

@@ -2,12 +2,7 @@
   "Version": "{version}",
   "TypeName": "GWallet.Backend.MarshalledException",
   "Value": {
-    "HumanReadableSummary": {
-      "ExceptionType": "GWallet.Backend.Tests.CustomFSharpException",
-      "Message": "Exception of type 'GWallet.Backend.Tests.CustomFSharpException' was thrown.",
-      "StackTrace": "",
-      "InnerException": null
-    },
-    "FullBinaryForm": "{binaryMarshalledException}"
+    "DateTimeUtc": "<this value is not compared in tests>",
+    "FullDescription": "GWallet.Backend.Tests.CustomFSharpException: CustomFSharpException"
   }
 }

src/GWallet.Backend.Tests/data/innerException.json

@@ -2,22 +2,7 @@
   "Version": "{version}",
   "TypeName": "GWallet.Backend.MarshalledException",
   "Value": {
-    "HumanReadableSummary": {
-      "ExceptionType": "System.Exception",
-      "Message": "msg",
-      "StackTrace": "",
-      "InnerException": {
-        "Case": "Some",
-        "Fields": [
-          {
-            "ExceptionType": "System.Exception",
-            "Message": "innerMsg",
-            "StackTrace": "",
-            "InnerException": null
-          }
-        ]
-      }
-    },
-    "FullBinaryForm": "{binaryMarshalledException}"
+    "DateTimeUtc": "<this value is not compared in tests>",
+    "FullDescription": "GWallet.Backend.Tests.CustomFSharpException: CustomFSharpException"
   }
 }