Opt into IncludePackageReferencesDuringMarkupCompilation

[sfoslund]

Fixes #15395

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this PR. If you have write-permissions please help me learn by adding exactly one area label.

[clairernovotny]

I don't know where the right place in the SDK is for this, so I can't speak to that, but otherwise LGTM

[dsplaisted]

Normally I would put this in a .targets file, though it would need to come before Microsoft.WinFX.targets where it's defaulted to false.

Is it possible to add a test for the end-to-end scenario here, ie using source generators in a WPF project or one of the other scenarios this unblocks?

[clairernovotny]

True, a targets file would make it easier for a user to disable it in their csproj if they wanted to.

It should be possible to test for this.

[dsplaisted]

Note that testing this might require updating to a stage 0 version which has the WPF fix.

[sfoslund]

Note that testing this might require updating to a stage 0 version which has the WPF fix.

@dsplaisted it looks like there isn't a 5.0.200 build that can be used for stage 0 that has all the changes. Specifically I'm looking at the latest 5.0.200 build locally (5.0.200-preview.21074.4) and it doesn't contain any of the changes from https://github.com/dotnet/wpf/pull/3846/files

Edit: we haven't updated our wpf version since December 10th, the day before the WPF changes were merged: https://github.com/dotnet/sdk/blame/release/5.0.2xx/eng/Versions.props#L135

[sfoslund]

Test should pass when we get a build to use as stage 0 from this PR: #15492

[dsplaisted]

I was confused about stage 0, I think we don't actually need a stage 0 round-trip, we just need the WPF update merged.

[sfoslund]

@dsplaisted this is passing locally with the wpf update, are we good to merge once it's green?

[dsplaisted]

@sfoslund LGTM

[sfoslund]

Thanks for merging @wli3!

[bording]

Normally I would put this in a .targets file, though it would need to come before Microsoft.WinFX.targets where it's defaulted to false.

Just curious, if Microsoft.WinFX.targets is defaulting it to false, why not change make the change there to default to true instead of effectively doing that with the change here?

[clairernovotny]

Normally I would put this in a .targets file, though it would need to come before Microsoft.WinFX.targets where it's defaulted to false.

Just curious, if Microsoft.WinFX.targets is defaulting it to false, why not change make the change there to default to true instead of effectively doing that with the change here?

The reason is that WPF is part of the runtime, ships in 5.0.2/5.0.3 and they can't change the default behavior there. The SDK is expected to change features (in a compatible way) from release to release, so we can flip the default here. WPF has an issue to make it on by default for .NET 6 here: dotnet/wpf#3974