After added and '$(TargetFrameworkMonikerAssemblyAttributeText)' != '' to the Condition on the Target. The condition on the target is false all the time even though $(TargetFrameworkMonikerAssemblyAttributeText) is not empty. It seems target condition is evaluated in the Evalution time not the execution time.
Here is the binlog
msbuild9840.binlog.txt

<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <Target Name="FirstTarget" BeforeTargets="SecondTarget">
    <!-- Define a property inside the first target -->
    <PropertyGroup>
      <ConditionProperty>ConditionValue</ConditionProperty>
    </PropertyGroup>
    <Message Text="Executing FirstTarget" />
  </Target>  
  <Target Name="SecondTarget" Condition="'$(ConditionProperty)' == 'ConditionValue'" >
    <Message Text="Executing SecondTarget" />
  </Target>
</Project>

msbuild /t:SecondTarget doesn't output the secondtarget message.

Thank you @JaynieBai !

I tried it out too and got the exact same result.

This is because $(TargetFrameworkMonikerAssemblyAttributeText) property is set inside another target _SetTargetFrameworkMonikerAttribute
https://github.com/dotnet/msbuild/blob/main/src/Tasks/Microsoft.VisualBasic.CurrentVersion.targets#L332
https://github.com/dotnet/msbuild/blob/main/src/Tasks/Microsoft.CSharp.CurrentVersion.targets#L331

If we add and '$(TargetFrameworkMonikerAssemblyAttributeText)' != '' to the condition on GenerateTargetFrameworkMonikerAttribute target, then the condition is always false and target is never run (see Jenny's example).

Another solution could be to remove _SetTargetFrameworkMonikerAttribute and instead set the property outside of any target, then we can add and '$(TargetFrameworkMonikerAssemblyAttributeText)' != '' to the Condition on GenerateTargetFrameworkMonikerAttribute target. @KirillOsenkov what do you think?

It seems target condition is evaluated in the Evalution time not the execution time.

This is not quite right--it's more complicated :( The docs at https://learn.microsoft.com/en-us/visualstudio/msbuild/target-build-order?view=vs-2022#determine-the-target-build-order are accurate, but you have to read them about 300 times before they sink in. I did, anyway . . .

What happens in your example is that the condition is evaluated between seeing the target for the first time (when the build starts, because you specified it as the entry-point target) and running the BeforeTargets, so the condition observes project state before FirstTarget runs.

thanks Rainer! I wasn't looking forward to digging in deeper to understand this :)

I'm going to bow out if you excuse me :)

@surayya-MS can you try:

1. Extract the current body of GenerateTargetFrameworkMonikerAttribute to a new target _WriteTargetFrameworkMonikerAttributeToFile (name arbitrary), including Inputs/Outputs
2. Make GenerateTargetFrameworkMonikerAttribute have DependsOnTargets="PrepareForBuild;GetReferenceAssemblyPaths;_WriteTargetFrameworkMonikerAttributeToFile"
3. Make _WriteTargetFrameworkMonikerAttributeToFile have Condition="'@(Compile)' != '' and '$(GenerateTargetFrameworkAttribute)' == 'true' and '$(TargetFrameworkMonikerAssemblyAttributeText)' != '' "

That should delay the evaluation of the condition to the point where it's already computed, so the target can be conditioned out rather than marked out of date.