[C#] fix net35 with JsonSubTypes

[manuc66]

PR checklist

• Read the contribution guidelines.
• Ran the shell script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh and ./bin/security/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates). Windows batch files can be found in .\bin\windows\.
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Description of the PR

As mentioned in #6969 this PR update JsonSubTypes to 1.2.0 which is compatible with NET35 without API changes.

As suggested I updated compile.mustache

In order to validate the NET35 compliance I added a new sample generation samples\client\petstore\csharp\SwaggerClientNet35\

Here is the compilation status of sample available in the project:

project	build.cmd build status	build. sh build status	VS2017 build status
csharp\SwaggerClient	OK	OK	OK
csharp\SwaggerClientWithPropertyChanged	OK	OK	OK
csharp\SwaggerClientNet35	NOT OK	OK	OK
csharp\SwaggerClientNet40	NOT OK	OK	OK
csharp\SwaggerClientNetCoreProject	na	na	OK
csharp\SwaggerClientNetStandard	na	na	OK

The two NOT OK are not related to this PR nor #6969 but seems to be related to the usage of csc

cc: @mandrean, @jimschubert

[jimschubert]

The change looks good.

What are the errors present in .NET 3.5/4.0 compile scripts? These worked previously (I resolved any issues about a week or two ago), before changing to the nuget package. Are you on an older version if mono, maybe?

I'll verify against this branch when I'm at a computer either tonight or tomorrow and report back with my mono version.

If it's a mono version issue, we'll want to open another pr to check for a minimum version before compilation, so there's no unknowns in build scripts. That's probably a good idea, anyway.

[manuc66]

@jimschubert I did not try on linux/mono but on windows only.

It looks like the windows scripts are at least missing the langversion configuration. But are those kind of scripts making senses on windows ?

Here are the windows build.log:
SwaggerClientNet35.windows.build.log
SwaggerClientNet40.windows.build.log

[jimschubert]

@manuc66 on Windows, I think it's a little different. If you're on Windows 10, I don't know if you'll be able to install .net 3.5 or 4.0. .net 4.5 is an in place install over .net 4.0, which may compile differently than having only .net 4.0 installed.

I'll need to download the IE developer images again to check.

[manuc66]

@jimschubert

If I do use msbuild instead of csc on Windows the compilation works:

For net35:

if not exist ".\nuget.exe" powershell -Command "(new-object System.Net.WebClient).DownloadFile('https://dist.nuget.org/win-x86-commandline/latest/nuget.exe', '.\nuget.exe')"
.\nuget.exe restore

%SYSTEMROOT%\Microsoft.NET\Framework\v4.0.30319\msbuild IO.Swagger.sln /p:TargetFramework=3.5

See: https://pastebin.com/ZrCfdbrS

For net40 I still have issue with msbuild that I don't have with VS 2017:

if not exist ".\nuget.exe" powershell -Command "(new-object System.Net.WebClient).DownloadFile('https://dist.nuget.org/win-x86-commandline/latest/nuget.exe', '.\nuget.exe')"
.\nuget.exe restore

%SYSTEMROOT%\Microsoft.NET\Framework\v4.0.30319\msbuild IO.Swagger.sln /p:TargetFramework=4.0

see: https://pastebin.com/5mCLTqn7 (in fact that's only the test library that is failing to build)

[jimschubert]

@manuc66 were you ever able to resolve the issue with .NET 4.0? I intended to test this out but my VM drive crapped out and my main machine didn't have enough space for running a VM. I've upgraded my machine, and could take a look now if you were unable to.

[manuc66]

@jimschubert I did not found a solution for the compilation errors that are linked to the use of csc in the compilation stage.

Note that:

• the generated code can be build with VS2017
• the errors generated by csc are not related to the changes made by this PR
• there is no build error on Linux

[wing328]

Thanks @manuc66.

We plan to release 2.3.0 today or tomorrow so I hope we can this into master as well.

[wing328]

I tested build.sh for the following folders and the result is good:

SwaggerClient
SwaggerClientNet40
SwaggerClientNet35
SwaggerClientWithPropertyChanged