IncrementalClean deletes transitively-acquired content in Visual Studio

[rainersigwald]

[This is based on feedback from connect.microsoft.com.]

If you have:

• A project that copies some files to the output directory (call it ClassLibraryIndirect)
• A project that depends on ClassLibraryIndirect (call it ClassLibraryDirect)
• A project that depends on ClassLibraryDirect (call it IncrementalClean)

And you build using Visual Studio, some very surprising behavior can occur.

Demo projects: https://github.com/rainersigwald/IncrementalCleanDemo

On the first (full) build of the main project, the output file is present in ClassLibraryIndirect's bin directory, and in IncrementalClean's--as expected. Content files should be transitively passed along. Selected state.

If you make a change to the main project (to get VS's fast-up-to-date check to cause an actual build) and build just it again, the content file gets deleted from the main project's bin directory. changes

Looking through a diag-level log of the second build, the problem is that the IncrementalClean target deletes the file, because it incorrectly thinks it's no longer an output.

This does not happen when building from the command line using no special properties.

But it does happen when building from the command line setting the property BuildProjectReferences=false, which simulates Visual Studio's mechanism of building individual projects.

Whether or not a project is built in isolation should not affect the outputs it produces.

[rainersigwald]

The proximate cause of this is that the transitive GetCopyToOutputDirectoryItems target doesn't include the indirect content file in the latter build, while it does in the initial, successful build as well as the successful full command-line build.

There's a very confusing comment for GetCopyToOutputDirectoryItems that indicates that it isn't transitive--but clearly sometimes it is.

[kzu]

We're hitting this too, trying to improve the way we perform the Pdb>Mdb in-place, and not getting them copied transitively :(

[abbottbd]

+1 this has been a thorn in our side at work for ages!

[aswinraaj]

We are getting the same problem when using sonarqube for performing static code analysis which creates temporary files . Incremental clean deletes it before the entire solution is even completed building

[jcouv]

+1 I'm hitting this daily in my inner development loop.

[angularsen]

We worked around this by moving all content files from each individual library, where we feel they naturally belong, to dumping all of them in our main app project. It's not pretty, but it works. We have spent way too much time investigating this and very frustrated to see the age of this problem and no update on fixing this.

[KirillOsenkov]

We've been hitting this as well and the easy workaround we found is to add:

<Target Name="IncrementalClean" />

to a .targets file that's included in all projects. Disabling incremental clean is mostly harmless since we regularly do git clean -xdff anyway. A decent workaround.

[rainersigwald]

Another workaround is to flatten your dependency tree: ensure that there are direct ProjectReferences instead of relying on transitive copying behavior.

[gulbanana]

I can confirm that I was extremely surprised by this behaviour. The symptom is a failure to pack, since the PDB files which have been deleted aren't present as an input to nuget, which the pack targets require even if you aren't building a symbol package..

[gulbanana]

Actually I'm not totally sure it's the same issue, but it seems very similar. My problem is the same one that's described in this StackOverflow question: https://stackoverflow.com/questions/44175371/pdb-file-is-being-removed-by-target-incrementalclean

[herrgruebner]

2018 and still going on. Was a fun one to track down.