ArgumentOutOfRangeException during Build with Tools 12.0 - msbuild

Question

We have an (old) build definition is using the UpgradeTemplate.xaml on TFS 2015 (and an underlying TFSBuild.proj which has a heap of custom actions). As such, the task of properly modernising the build is going to take time.
I'd like to hack the UpgradeTemplate to add in C#6/VB14 support without requiring a full re-write of the build definition, in order to keep the devs happy.
I attempted to edit the UpgradeTemplate.xaml to add a ToolPath property on the TfsBuild. However, now that I have done this, I get the following error on nearly all my projects:
ArgumentOutOfRangeException: Index and length must refer to a location within the string. Parameter name: length
On investigation, the lines of code in these projects all look like this:
<MSBuild.ExtensionPack.VisualStudio.TfsVersion TaskAction="GetVersion"
BuildName="$(BuildDefinition)" TfsBuildNumber="$(BuildNumber)"
VersionFormat="DateTime" DateFormat="MMdd" Major="$(MajorVersion)"
Minor="$(MinorVersion)">
The values of these variables as set printed out by Message tasks on the vbproj:
BuildDefinition: MyBuild-Testing
BuildNumber: 57902
MajorVersion: 43
MinorVersion: 2
The Build server has version 3.5.10 on the MSBuild ExtensionPack installed.
How do I resolve this issue? I'm testing this with a new build definition to allow devs to continue working while I get this set up, so I don't want to replace the ExtensionPack with the latest release (if possible) if it is likely to break the existing build.
Upgrade Template
<Activity mc:Ignorable="sad" x:Class="TfsBuild.Process" xmlns="http://schemas.microsoft.com/netfx/2009/xaml/activities" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:mtbc="clr-namespace:Microsoft.TeamFoundation.Build.Client;assembly=Microsoft.TeamFoundation.Build.Client" xmlns:mtbw="clr-namespace:Microsoft.TeamFoundation.Build.Workflow;assembly=Microsoft.TeamFoundation.Build.Workflow" xmlns:mtbwa="clr-namespace:Microsoft.TeamFoundation.Build.Workflow.Activities;assembly=Microsoft.TeamFoundation.Build.Workflow" xmlns:mtbwt="clr-namespace:Microsoft.TeamFoundation.Build.Workflow.Tracking;assembly=Microsoft.TeamFoundation.Build.Workflow" xmlns:mtvc="clr-namespace:Microsoft.TeamFoundation.VersionControl.Client;assembly=Microsoft.TeamFoundation.VersionControl.Client" xmlns:mva="clr-namespace:Microsoft.VisualBasic.Activities;assembly=System.Activities" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:sad="http://schemas.microsoft.com/netfx/2009/xaml/activities/presentation" xmlns:sad1="clr-namespace:System.Activities.Debugger;assembly=System.Activities" xmlns:scg="clr-namespace:System.Collections.Generic;assembly=mscorlib" xmlns:this="clr-namespace:TfsBuild;" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<x:Members>
<x:Property Name="ConfigurationFolderPath" Type="InArgument(x:String)" />
<x:Property Name="AgentSettings" Type="InArgument(mtbwa:AgentSettings)" />
<x:Property Name="MSBuildArguments" Type="InArgument(x:String)" />
<x:Property Name="MSBuildPlatform" Type="InArgument(mtbwa:ToolPlatform)" />
<x:Property Name="DoNotDownloadBuildType" Type="InArgument(x:Boolean)" />
<x:Property Name="LogFilePerProject" Type="InArgument(x:Boolean)" />
<x:Property Name="SourcesSubdirectory" Type="InArgument(x:String)" />
<x:Property Name="BinariesSubdirectory" Type="InArgument(x:String)" />
<x:Property Name="TestResultsSubdirectory" Type="InArgument(x:String)" />
<x:Property Name="RecursionType" Type="InArgument(mtvc:RecursionType)" />
<x:Property Name="Verbosity" Type="InArgument(mtbw:BuildVerbosity)" />
<x:Property Name="Metadata" Type="mtbw:ProcessParameterMetadataCollection" />
<x:Property Name="SupportedReasons" Type="mtbc:BuildReason" />
</x:Members>
<this:Process.ConfigurationFolderPath>
<InArgument x:TypeArguments="x:String" />
</this:Process.ConfigurationFolderPath>
<this:Process.AgentSettings>[New Microsoft.TeamFoundation.Build.Workflow.Activities.AgentSettings() With {.MaxWaitTime = New System.TimeSpan(4, 0, 0), .MaxExecutionTime = New System.TimeSpan(0, 0, 0), .TagComparison = Microsoft.TeamFoundation.Build.Workflow.Activities.TagComparison.MatchExactly }]</this:Process.AgentSettings>
<this:Process.MSBuildArguments>
<InArgument x:TypeArguments="x:String" />
</this:Process.MSBuildArguments>
<this:Process.MSBuildPlatform>[Microsoft.TeamFoundation.Build.Workflow.Activities.ToolPlatform.Auto]</this:Process.MSBuildPlatform>
<this:Process.DoNotDownloadBuildType>[False]</this:Process.DoNotDownloadBuildType>
<this:Process.LogFilePerProject>[False]</this:Process.LogFilePerProject>
<this:Process.SourcesSubdirectory>
<InArgument x:TypeArguments="x:String" />
</this:Process.SourcesSubdirectory>
<this:Process.BinariesSubdirectory>
<InArgument x:TypeArguments="x:String" />
</this:Process.BinariesSubdirectory>
<this:Process.TestResultsSubdirectory>
<InArgument x:TypeArguments="x:String" />
</this:Process.TestResultsSubdirectory>
<this:Process.RecursionType>[Microsoft.TeamFoundation.VersionControl.Client.RecursionType.OneLevel]</this:Process.RecursionType>
<this:Process.Verbosity>[Microsoft.TeamFoundation.Build.Workflow.BuildVerbosity.Normal]</this:Process.Verbosity>
<this:Process.Metadata>
<mtbw:ProcessParameterMetadataCollection />
</this:Process.Metadata>
<this:Process.SupportedReasons>All</this:Process.SupportedReasons>
<mva:VisualBasic.Settings>Assembly references and imported namespaces serialized as XML namespaces</mva:VisualBasic.Settings>
<Sequence mtbwt:BuildTrackingParticipant.Importance="None">
<Sequence.Variables>
<Variable x:TypeArguments="mtbc:IBuildDetail" Name="BuildDetail" />
</Sequence.Variables>
<mtbwa:GetBuildDetail DisplayName="Get the Build" Result="[BuildDetail]" />
<mtbwa:InvokeForReason DisplayName="Update Build Number for Triggered Builds" Reason="Triggered">
<mtbwa:UpdateBuildNumber BuildNumberFormat="["$(BuildDefinitionName)_$(Date:yyyyMMdd)$(Rev:.r)"]" DisplayName="Update Build Number" />
</mtbwa:InvokeForReason>
<mtbwa:AgentScope DisplayName="Run On Agent" MaxExecutionTime="[AgentSettings.MaxExecutionTime]" MaxWaitTime="[AgentSettings.MaxWaitTime]" ReservationSpec="[AgentSettings.GetAgentReservationSpec()]">
<mtbwa:AgentScope.Variables>
<Variable x:TypeArguments="x:String" Name="buildDirectory" />
</mtbwa:AgentScope.Variables>
<mtbwa:GetBuildDirectory DisplayName="Get the Build Directory" Result="[buildDirectory]" />
<If Condition="[Not String.IsNullOrEmpty(ConfigurationFolderPath)]" DisplayName="If Not String.IsNullOrEmpty(ConfigurationFolderPath)">
<If.Then>
<mtbwa:TfsBuild BinariesSubdirectory="[BinariesSubdirectory]" BuildDirectory="[buildDirectory]" CommandLineArguments="[MSBuildArguments]" ConfigurationFolderPath="[ConfigurationFolderPath]" DisplayName="Run TfsBuild for Configuration Folder" DoNotDownloadBuildType="[DoNotDownloadBuildType]" LogFilePerProject="[LogFilePerProject]" RecursionType="[RecursionType]" SourcesSubdirectory="[SourcesSubdirectory]" TestResultsSubdirectory="[TestResultsSubdirectory]" ToolPath="C:\Program Files (x86)\MSBuild\12.0\Bin\" ToolPlatform="[MSBuildPlatform]" Verbosity="[Verbosity]" />
</If.Then>
</If>
<If Condition="[BuildDetail.CompilationStatus = Microsoft.TeamFoundation.Build.Client.BuildPhaseStatus.Unknown]" DisplayName="If CompilationStatus = Unknown">
<If.Then>
<mtbwa:SetBuildProperties CompilationStatus="[Microsoft.TeamFoundation.Build.Client.BuildPhaseStatus.Succeeded]" DisplayName="Set CompilationStatus to Succeeded" PropertiesToSet="CompilationStatus" />
</If.Then>
</If>
<If Condition="[BuildDetail.TestStatus = Microsoft.TeamFoundation.Build.Client.BuildPhaseStatus.Unknown]" DisplayName="If TestStatus = Unknown">
<If.Then>
<mtbwa:SetBuildProperties DisplayName="Set TestStatus to Succeeded" PropertiesToSet="TestStatus" TestStatus="[Microsoft.TeamFoundation.Build.Client.BuildPhaseStatus.Succeeded]" />
</If.Then>
</If>
</mtbwa:AgentScope>
<mtbwa:InvokeForReason Reason="CheckInShelveset">
<mtbwa:CheckInGatedChanges DisplayName="Check In Gated Changes" />
</mtbwa:InvokeForReason>
</Sequence>
</Activity>
In Particular, I added ToolPath="C:\Program Files (x86)\MSBuild\12.0\Bin\" to line 58.
TFSBuild.proj
<?xml version="1.0" encoding="utf-8"?>
<Project DefaultTargets="DesktopBuild" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0">
<Import Project="$(MSBuildExtensionsPath)\Microsoft\VisualStudio\TeamBuild\Microsoft.TeamFoundation.Build.targets" />
<Import Project="$(MSBuildExtensionsPath)\Microsoft\SDC\Microsoft.Sdc.Common.tasks" />
<Import Project="$(MSBuildExtensionsPath)\ExtensionPack\MSBuild.ExtensionPack.tasks"/>
<ProjectExtensions>
<!-- Team Foundation Build Version - DO NOT CHANGE -->
<ProjectFileVersion>2</ProjectFileVersion>
</ProjectExtensions>
<PropertyGroup>
<RunCodeAnalysis>Never</RunCodeAnalysis>
<UpdateAssociatedWorkItems>false</UpdateAssociatedWorkItems>
<AdditionalVCOverrides></AdditionalVCOverrides>
<CustomPropertiesForClean></CustomPropertiesForClean>
<CustomPropertiesForBuild></CustomPropertiesForBuild>
<SkipGetChangesetsAndUpdateWorkItems>False</SkipGetChangesetsAndUpdateWorkItems>
<SkipWorkItemCreation>true</SkipWorkItemCreation>
<BuildConfigurationsInParallel>true</BuildConfigurationsInParallel>
<SkipDropBuild>false</SkipDropBuild>
</PropertyGroup>
<ItemGroup>
<SolutionToBuild Include="$(BuildProjectFolderPath)/SolutionsToBuild/Common.sln">
<Targets></Targets>
<Properties></Properties>
</SolutionToBuild>
</ItemGroup>
<ItemGroup>
<ConfigurationToBuild Include="Release|Any CPU">
<FlavorToBuild>Release</FlavorToBuild>
<PlatformToBuild>Any CPU</PlatformToBuild>
</ConfigurationToBuild>
</ItemGroup>
<PropertyGroup>
<SkipClean>false</SkipClean>
<SkipInitializeWorkspace>true</SkipInitializeWorkspace>
<ForceGet>true</ForceGet>
<IncrementalBuild>false</IncrementalBuild>
</PropertyGroup>
</Project>
Update
I think it might be something to do with running a private build (Latest + Shelveset). When I run a normal build, the BuildNumber variable is MyBuild-Testing_20170328.1. This appears to be working fine.

Answer 1

This issue is due to a difference between Private and Public builds. With Public Builds, the build is immediately numbered as BuildName_DateFormat.BuildNumber. Private builds however, are just numeric (e.g. 57902 above).
The Code in the extension does the following:
string buildstring = this.TfsBuildNumber.Replace(string.Concat(this.BuildName, "_"),
string.Empty);
char[] chrArray = new char[] { '.' };
string[] buildParts = buildstring.Split(chrArray, StringSplitOptions.RemoveEmptyEntries);
DateTime t = new DateTime(Convert.ToInt32(buildParts[0].Substring(0, 4),
CultureInfo.CurrentCulture),
Convert.ToInt32(buildParts[0].Substring(4, 2),
CultureInfo.CurrentCulture),
Convert.ToInt32(buildParts[0].Substring(6, 2),
CultureInfo.InvariantCulture));
Are you can see, its substringing on the build name, assuming it's been stripped down to the date component (20170328). Private builds aren't this long, and so fail.
This build works fine when running as a public build - basically it means that private builds on this definition are not available until an upgrade takes place.