Task factories Shows Misleading Errors When Failing on internal operations

[benvillalobos]

Issue Description

Found in https://dev.azure.com/devdiv/DevDiv/_workitems/edit/1272722

Building a project that uses a task factory that fails to parse its input, the error reported is misleading. See below for the error. It should be something like "TaskFactory Failed: {stack-trace-etc}".

Steps to Reproduce

Build a project/xaml file like so:

project.proj

<Project>
<Target Name="Entry">
    <CudaCompile ToolExe="cmd.exe"/>
</Target>
<UsingTask TaskName="CudaCompile" TaskFactory="XamlTaskFactory" AssemblyName="Microsoft.Build.Tasks.v4.0, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
    <Task>Test.xaml</Task>
</UsingTask>
</Project>

test.xaml

<ProjectSchemaDefinitions xmlns=`clr-namespace:Microsoft.Build.Framework.XamlTypes;assembly=Microsoft.Build.Framework` xmlns:x=`http://schemas.microsoft.com/winfx/2006/xaml` xmlns:sys=`clr-namespace:System;assembly=mscorlib` xmlns:impl=`clr-namespace:Microsoft.VisualStudio.Project.Contracts.Implementation;assembly=Microsoft.VisualStudio.Project.Contracts.Implementation`>
    <Rule Name=`CL`>
        <EnumProperty Name=`GeneratePreprocessedFile` Switch=`nologo`>
            <EnumValue Name=`Disabled` />
            <EnumValue Name=`Yes` Switch=`P` />
            <EnumValue Name=`NoLineNumbers` Switch=`EP` />
        </EnumProperty>
    </Rule>
</ProjectSchemaDefinitions>

Expected Behavior

Error saying the task factory itself failed on the backticks existing in the xaml file.

Actual Behavior

We get both "taskfactory couldn't be loaded" and "

Build started 5/6/2021 2:11:30 PM.
Project "C:\src\issues\cudaproject\project.proj" on node 1 (default targets).
C:\src\issues\cudaproject\project.proj(3,5): error MSB4175: The task factory "XamlTaskFactory" could not be loaded 
from the assembly "Microsoft.Build.Tasks.v4.0, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a".  
'`' is an unexpected token. The expected token is '"' or '''. Line 1, position 33.
Done Building Project "C:\src\issues\cudaproject\project.proj" (default targets) -- FAILED.
Build FAILED.

Analysis

The error suggests the task factory was found just fine, but there was an error while parsing the xaml to create the task.

Versions & Configurations

msbuild --version

Microsoft (R) Build Engine version 16.10.0-dev-21205-01+86be06394 for .NET Framework
Copyright (C) Microsoft Corporation. All rights reserved.

16.10.0.20501

Notes

Does this also happen with other TaskFactory classes?

[benvillalobos]

Saw this when working with the roslyn task factory.

To repro: Create an inline task with any compiler error.

[benvillalobos]

Team Triage: We should consider changing the error message when an internal error in the factory comes up.

[benvillalobos]

That message should specifically not say "could not be loaded". Loaded is misleading, especially when it's a compiler error that happened when compiling within the factory.