dotnet build rebuilds every time when the project contains a pre/post-compile script and incremental build gets disabled

[prochan2]

Steps to reproduce

1. Create a new console (or any other) .NET Core app. (dotnet new)
2. Add any postcompile script to project.json.
3. Run dotnet build twice.

Expected behavior

1. First run of dotnet build builds the project.
2. Second run of dotnet build says `Project {project name} was previously compiled. Skipping compilation.

Actual behavior

Both runs of dotnet build rebuild the whole project.

Environment data

dotnet --info output:
.NET Command Line Tools (1.0.0-preview2-003133)

Product Information:
Version: 1.0.0-preview2-003133
Commit SHA-1 hash: 74df065

Runtime Environment:
OS Name: Windows
OS Version: 10.0.14393
OS Platform: Windows
RID: win10-x64

Notes

Let's say that the post-compile script does not do any change which would affect the incremental build. Wouldn't it be better to allow adding a flag to the script telling that the script is "incremental build friendly"?

[blackdwarf]

This was by design in Preview 2 I believe. https://docs.microsoft.com/en-us/dotnet/articles/core/tools/dotnet-build has all of the details.

In the MSBuild world, this is not applicable since MSBuild has a different way of providing post-target extensibility. With that, I will close this issue.