Can Exec task in msbuild fail if exitCode = 0 but there is logging to standard error? - msbuild

Question

I am curious about:
https://learn.microsoft.com/en-us/visualstudio/msbuild/exec-task?view=vs-2019
ExitCode Optional Int32 output read-only parameter.
Specifies the exit code that is provided by the executed command, except that if the task logged any errors, but the process had an exit code of 0 (success), ExitCode is set to -1.
Can msbuild fail on Exec even if process has an exit code of 0 but it logs to standard error?
I tried to make it fail with the following code:
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApp3
{
class Program
{
static int Main( string[] args )
{
using ( var stdErr = Console.Error )
{
for ( int i = 0; i <= 100; i++ )
{
stdErr.WriteLine( $"Failed to copy attempt {i}." );
System.Threading.Thread.Sleep( 50 );
}
// Close redirected error stream.
Console.Error.Close();
}
return 0;
}
}
}
It is being called as part of a standard props file.
<Target
Name = "IvaraSign"
AfterTargets="CoreBuild"
BeforeTargets="CopyFilesToOutputDirectory" >
<!-- Update version on main output -->
<!-- this works when the solution being compiled is in the dotnet folder. -->
<Exec Command="C:\Users\Derek.Morin\source\repos\ConsoleApp3\bin\Debug\ConsoleApp3.exe"/>
</Target>
When I build in msbuild I can see the error text in the build output but the compiling passes.

Answer 1

Does the MSBuild Exec task search STDOUT for the string "error"?
I was able to duplicate making exec file fail with the following
static int Main( string[] args )
{
using ( var stdErr = Console.Error )
{
stdErr.WriteLine( $#"signtool.exe : error information: ""Error: Store IsDiskFile() failed."" (-2147024864/0x80070020) [d:\work\1\s\common\MAFPlugins\MAFScripting\Contracts\Contracts.csproj]" );
}
Console.WriteLine( "but I'm still going to return 0" );
return 0;
}
The workaround is to use IgnoreStandardErrorWarningFormat="true".
<Exec Command="C:\ConsoleApp3\ConsoleApp3.exe" IgnoreStandardErrorWarningFormat="true" />