PMC + xproj: dotnet-ef uses incorrect build directory

[natemcmaster]

Steps to reproduce

File -> New ASP.NET Web Application (.NET Core)
Install Microsoft.EntityFrameworkCore.Tools 1.0.0-preview2-final
Add-Migration Initial -Verbose

The issue

PMC cmdlets will call dotnet-ef with the incorrect build base path option. In project that use global.json, this can cause .NET Core SDK to use ./bin/src/<projectName>/bin/ as the build directory instead of just ./bin/.

e.g.:

dotnet ef --build-base-path .\bin dbcontext list --verbose

In many cases, the PMC command will continue to function correctly. However, this causes problems for projects using SQLite and Update-Database. See aspnet/Microsoft.Data.Sqlite#275. In other cases, it causes misleading "class libraries not supported" errors.

Further technical details

PMC uses DTE to determine build base path. Before preview2, the behavior of web tooling in VS was to build in <solutionRoot>/bin/<projectName>. This was changed for preview 2 to instead use <projectDirectory>/bin/. dotnet-ef preview2 still uses the original behavior.

EF Core version: 1.0.0-preview2-final tooling
Visual Studio version: VS 2015 U3, Web Tooling Preview 2

Workaround

Use dotnet-ef directly and don't pass in the --build-base-path option.
Use absolute paths in connection strings for SQLite.

[bricelam]

I believe this issue went away with #6288.