"dotnet build" fails when schema cache is present for a PostgreSQL DB

[ScottShingler]

Description

Running dotnet build on a project that uses SqlProvider with Npgsql while a cached schema file is present fails to build. However, the same project is able to build from Visual Studio 2019 Version 16.2.4.

Repro steps

1. Create a basic PostgreSQL schema (single table is enough) and use SqlProvider to generate a schema cache via GetDataContext().SaveContextSchema() from Visual Studio 2019.

2. Exit Visual Studio.

3. Delete the bin and obj folders.

4. Run dotnet build.

Expected behavior

The project compiles without error.

Actual behavior

Build fails with the following error:

C:\Projects\MyProj\foo\src\MyProj.Dal\Database.fs(19,5): error FS3033: The type provider 'FSharp.Data.Sql.SqlTypeProvider' reported an error: The data contract type 'Microsoft.FSharp.Collections.FSharpMap`2[[System.String, System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[FSharp.Data.Sql.Schema.Column, FSharp.Data.SqlProvider, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]' cannot be deserialized because the required data members 'comparer, tree' were not found. [C:\Projects\MyProj\foo\src\MyProj.Dal\MyProj.Dal.fsproj]

Known workarounds

Delete the schema cache and instead have an instance of the database running. This is not ideal for CI builds.

Related information

• Used database: PostgreSQL 11.5 with Npgsql 4.0.10 (also tried with 4.0.9)
• Operating system: Windows 10 Pro
• Branch: master (SqlProvider 1.1.68)
• .NET Runtime, CoreCLR or Mono Version: .NET Core 2.2.401
• Performance information, links to performance testing scripts: N/A

Additional Information

Comparing the build command from Visual Studio and dotnet build reveals the following differences:

Property	Visual Studio	dotnet build
Path	c:\program files (x86)\microsoft visual studio\2019\professional\common7\ide\commonextensions\microsoft\fsharp\fsc.exe	C:\Program Files\dotnet\dotnet.exe "C:\Program Files\dotnet\sdk\2.2.401\FSharp\fsc.exe"
Version	Microsoft (R) F# Compiler version 10.5.0.0 for F# 4.6	Microsoft (R) F# Compiler version 10.4.0 for F# 4.6

[ScottShingler]

Turns out this problem can be resolved by upgrading to .NET Core 3.0-preview9, which has F# Compiler version 10.6.0.0 for F# 4.7.

[mcspud]

Have you seen this problem reassert itself in .netcore 3.0 + npgsql 4.0.1 or 4.1.0? Looks like on my end the generated schema files are no longer including fields (columns) and their type maps, just the names of the tables themselves.

[Thorium]

See the response at #644