Getting appveyor to do prerelease and release nuget packages based on branch versus tag builds

appveyor.yml

version: 1.{build}.0
os: Visual Studio 2015
configuration: Release
platform: Any CPU
init:
- ps: $env:customnugetversion = if ($env:APPVEYOR_REPO_TAG -eq $True) { "$env:APPVEYOR_BUILD_VERSION" } else { "$env:APPVEYOR_BUILD_VERSION-$env:APPVEYOR_REPO_BRANCH" }
- ps: Update-AppveyorBuild -Version $env:customnugetversion

assembly_info:
  patch: true
  file: '**\AssemblyInfo.*'
  assembly_version: '{version}'
  assembly_file_version: '{version}'
  assembly_informational_version: '{version}'
  
before_build:
- ps: nuget restore

build:
  publish_nuget: true
  publish_nuget_symbols: true
  verbosity: minimal
  
deploy:
- provider: NuGet
  server: https://www.myget.org/blahblahblah
  api_key:
    secure: blahblah
  

AssemblyInfo.cs

using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

// General Information about an assembly is controlled through the following 
// set of attributes. Change these attribute values to modify the information
// associated with an assembly.
[assembly: AssemblyTitle( "MyAssembly" )]
[assembly: AssemblyDescription( "" )]
[assembly: AssemblyConfiguration( "" )]
[assembly: AssemblyCompany( "" )]
[assembly: AssemblyProduct( "Awesomeness2016" )]
[assembly: AssemblyCopyright( "Copyright ©  2016" )]
[assembly: AssemblyTrademark( "" )]
[assembly: AssemblyCulture( "" )]
[assembly: AssemblyVersion( "1.0.0.0" )]
[assembly: AssemblyFileVersion( "1.0.0.0" )]

// This attribute is important as it is what is referenced for the $version$ part of the nuspec
[assembly: AssemblyInformationalVersion( "1.0.0.0" ) ]

The key is to have the AssemblyInformationalVersion attribute in the AssemblyInfo.cs as that is what gets used for the $version$ field substitution in the nuspec.

https://gist.github.com/somewhatabstract/b2f2fe384b77a9c1e069f908bb3c4568#file-assemblyinfo-cs-L20

The other part is the scripts that init appveyor with a different version based off whether it's a tag build or not. The numeric versions ignore the additional string, but the informational attribute does not.

https://gist.github.com/somewhatabstract/b2f2fe384b77a9c1e069f908bb3c4568#file-appveyor-yaml-L6-L7

Push changes to a branch and it builds a nuget package with a prerelease -branchname at the end.

Push a tag and it builds a nuget package without that prerelease bit.

Ah so you always deploy to MyGet? I have a MyGet/NuGet setup for pre-release/release. But I'm pretty sure AppVeyor alllows different targets. Hmmmmm...