Optimize the pipeline by reduce the disk usage and build time

[licanhua]

We are starting to hit the 'not enough space' issue(see https://dev.azure.com/ms/react-native-windows/_build/results?buildId=47129). Currently I workaround the problem by deleting the buildout of ReactWindows-Desktop.sln before it builds Playground project.

There are possible two places we can improve:

1. Reduce the build time of some jobs
2. We didn't reuse the buildout put of vnext/ReactWindows-Desktop.sln in the next Playground project. so it hits not enough space.

not enough space error:

 ##[error]C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\amd64\Microsoft.Common.CurrentVersion.targets(4365,5): Error MSB3021: Unable to copy file "d:\a\1\s\vnext\target\x64\Debug\ReactUWP\React.UWP.pdb" to "d:\a\1\s\packages\playground\windows\x64\Debug\Playground\React.UWP.pdb". There is not enough space on the disk.

[JunielKatarn]

I am confused. How is ReactWindows-Desktop.sln related to the Playground project?
The only failures that show in the link provided are related to the Universal variant.
Do you perhaps mean ReactWindows-Universal.sln? The Desktop solution gets build exactly 4 times:

[acoates-ms]

Playground is a standalone solution, that look much more like a normal user of RNW would look like.
Its in packages/playground/windows/Playground.sln.

[chrisglein]

We either need to address this by upgrading the machine pool (which costs money) or improving our disk usage. We can work on the latter while we're having conversations about the former.

[licanhua]

I tried https://devblogs.microsoft.com/cppblog/shared-pch-usage-sample-in-visual-studio/, but I have two problems to go with this solution:

1. Although only one project used WinUI nuget, to use the shared precompile header, I need to move WinUI dependency to shared-pch project, then all cppwinrt projects depends on WinUI.
2. The projects have different PreprocessorDefinitions, AdditionalOptions and other settings, and finally the compiler complains the incompatibility with the shared header.

C++ modules may resolve this problem in the future, we it needs compiler support.

For the short term solution:

1. reduce the size of nuget packages by removing duplication. For example Use ReactNative.V8JSI.Windows.0.1.6 and ReactNative.Hermes.Windows.0.1.6 #3729 will reduce 1.3G
2. redirect the BaseIntDir part from D to C in pipeline, it will reduce 6G

[JunielKatarn]

Should we perhaps rename this issue? It doesn't appear to be related to the Desktop solution.

[JunielKatarn]

@licanhua I believe we are placing several packages folders in the repo.
One in the root for the Universal and Desktop solution, and one for each Playground/Sample solution location.

If we use environment/build variables smartly, we should be able to consolidate all packages in a single folder, avoiding such duplication.