Feature that adds vcpkg item to project settings in visual studio breaks builds that set VcpkgTriplet in .vcxproj, introduces other odd behaviors

[aggieNick02]

Commit 1451450 seems really problematic. While being able to edit these properties in the VS GUI is awesome, the issues it is causing are serious to enough to justify reverting until they are addressed.

If I have an existing project with VcpkgTriplet set in the .vcxproj as the documentation suggests, then before the commit, vcpkg respects that triplet. After, it does not. Additionally, there are other bits of wonky behavior I'm seeing, depending on machine and VS version.

Environment
Reproduced as follows. Imagine happens on VS2017 as well.

• OS: Windows 1903, Windows 1909
• Compiler: VS2015, VS2019

To Reproduce
Steps to reproduce:

• Begin by creating a vcpkg install right before the commit. We'll install the "minhook" package just to have something to include. From powershell, run

git clone https://github.com/Microsoft/vcpkg.git vcpkg_before
cd vcpkg_before
git checkout 14514508d8d30bdbd645b2bec89696aec25497f1~1
.\bootstrap-vcpkg.bat
.\vcpkg.exe integrate install
.\vcpkg.exe install minhook:x86-windows-static

• Leave powershell open.
• Now start visual studio (reproduced with 2015 and 2019), create a new c++ console application project with solution, and then edit the .vcxproj project file to have the line:
  <VcpkgTriplet>x86-windows-static</VcpkgTriplet>
  at the bottom of the
  <PropertyGroup Label="Globals">
  section. Reload the project when visual studio prompts. Then add
  #include "minhook.h"
  immediately before the main() function.
• Build the solution. It will succeed.
• Now close visual studio. We will now move to vcpkg with the problematic commit.
  Go back to powershell in vcpkg_before and run the following commands:

.\vcpkg.exe integrate remove
cd ..
git clone https://github.com/Microsoft/vcpkg.git vcpkg_after
cd vcpkg_after
git checkout 14514508d8d30bdbd645b2bec89696aec25497f1
.\bootstrap-vcpkg.bat
.\vcpkg.exe integrate install
.\vcpkg.exe install minhook:x86-windows-static

• Now launch visual studio and open the previous solution. Rebuild the solution. It fails.
• Note that the build output specifies that it is using x86-windows even though the project file specifies x86-windows-static.
• In VS2015 only, if you move the
  <VcpkgTriplet>x86-windows-static</VcpkgTriplet>
  line in the vcxproj to the "Configuration" PropertyGroup for Debug|Win32, it will then use "x86-windows-static", which is correct, but from the wrong location "C:\vckpg_after\installed\x86-windows", and still fail.
• On a non-clean windows image (my dev machine with a slightly older VS2015 Update 3 (14.0.25425.01), the behavior is even wonkier. In that scenario, the triplet in the property page is defaulted to "$(PlatformTarget)-$(VcpkgOSTarget)" and building with vcpkg_after outputs
  "Using triplet "-windows" from "F:\vcpkg\installed\-windows\"

Expected behavior
Updating to the latest vcpkg should not break existing working projects

[aggieNick02]

Sorry for the noise as I figured out git markdown and fixed typos. It should be stable now. Let me know if you want any files to repro or more details. I imagine this will break any project that prefers to link statically to vcpkg dependencies, so reverting may be prudent.

@Neumann-A @cbezault @BillyONeal @ras0219-msft

Also, once this new feature is in and stable, the documentation should probably updated to explain both the new functionality and its relation to setting VcpkgTriplet directly in the .vcxproj.

[BillyONeal]

This is because we accidentally overwrite VcpkgTriplet even when it has already been set in your project file.

[BillyONeal]

vcpkg/scripts/buildsystems/msbuild/vcpkg.targets

Line 44 in aef8385

<VcpkgTriplet Condition="'$(VcpkgTriplet)'!='$(VcpkgUserTriplet)'">$(VcpkgUserTriplet)</VcpkgTriplet>

<-- Right here. I wanted to give Nicole's change ~2 days to land to avoid another merge mess as it heavily edits that file to add manifests.

[aggieNick02]

That makes sense, thanks for pointing out where it is happening. I'm not sure how the wonky behavior in 2015 is happening (where the VcpkgTriplet is sometimes honored but the corresponding directory is wrong)... might be worth considering just disabling 2015 support if necessary.

[aggieNick02]

Just as a heads up, the issue filed at #12086 is mentioned in this issue as an "odd behavior", and caused by the same commit.

[aggieNick02]

Just checking in on this issue as it seems pretty critical. Any ETA? Is the current plan to rollback the problematic commit or to remedy it?

[ras0219]

I'm looking into this now.