.NET 6 trimmed mode=link application option throws Exception

[EjaYF]

We are using Npgsql.EntityFrameworkCore.PostgreSQL in a .NET 6 console application which we deploy using

 dotnet publish ./App.csproj -c Release -o out  \
                      --no-restore \  
                      --runtime alpine-x64 \
                      --self-contained true \
                      -p:PublishTrimmed=true \
                      -p:PublishSingleFile=true \
                      -p:TrimMode=Link 

in .NET 5 this had no issues running, but in .NET 6 (as the core .NET 6 libraries now support trimming mode Link) an Exception is thrown while querying the database:

Unhandled exception. System.TypeInitializationException: The type initializer for 'Npgsql.EntityFrameworkCore.PostgreSQL.Query.ExpressionTranslators.Internal.NpgsqlMathTranslator' threw an exception.
 ---> System.InvalidOperationException: Could not find method 'Truncate' on type 'System.Math'
   at System.SharedTypeExtensions.GetRequiredRuntimeMethod(Type type, String name, Type[] parameters)
   at Npgsql.EntityFrameworkCore.PostgreSQL.Query.ExpressionTranslators.Internal.NpgsqlMathTranslator..cctor()
   --- End of inner exception stack trace ---
   at Npgsql.EntityFrameworkCore.PostgreSQL.Query.ExpressionTranslators.Internal.NpgsqlMathTranslator.Translate(SqlExpression instance, MethodInfo method, IReadOnlyList`1 arguments, IDiagnosticsLogger`1 logger)
   at Microsoft.EntityFrameworkCore.Query.RelationalMethodCallTranslatorProvider.<>c__DisplayClass7_0.<Translate>b__0(IMethodCallTranslator t)
   at System.Linq.Enumerable.SelectEnumerableIterator`2.MoveNext()
   at System.Linq.Enumerable.TryGetFirst[TSource](IEnumerable`1 source, Func`2 predicate, Boolean& found)
   at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source, Func`2 predicate)
   at Microsoft.EntityFrameworkCore.Query.RelationalMethodCallTranslatorProvider.Translate(IModel model, SqlExpression instance, MethodInfo method, IReadOnlyList`1 arguments, IDiagnosticsLogger`1 logger)
   at Microsoft.EntityFrameworkCore.Query.RelationalSqlTranslatingExpressionVisitor.VisitMethodCall(MethodCallExpression methodCallExpression)
   at Npgsql.EntityFrameworkCore.PostgreSQL.Query.Internal.NpgsqlSqlTranslatingExpressionVisitor.VisitMethodCall(MethodCallExpression methodCall)
   at System.Linq.Expressions.MethodCallExpression.Accept(ExpressionVisitor )
   at System.Linq.Expressions.ExpressionVisitor.Visit(Expression node)
   at Microsoft.EntityFrameworkCore.Query.RelationalSqlTranslatingExpressionVisitor.TryRewriteEntityEquality(ExpressionType nodeType, Expression left, Expression right, Boolean equalsMethod, Expression& result)
   at Microsoft.EntityFrameworkCore.Query.RelationalSqlTranslatingExpressionVisitor.VisitBinary(BinaryExpression binaryExpression)
   at Npgsql.EntityFrameworkCore.PostgreSQL.Query.Internal.NpgsqlSqlTranslatingExpressionVisitor.VisitBinary(BinaryExpression binaryExpression)
   at System.Linq.Expressions.BinaryExpression.Accept(ExpressionVisitor )
   at System.Linq.Expressions.ExpressionVisitor.Visit(Expression node)
   at Microsoft.EntityFrameworkCore.Query.RelationalSqlTranslatingExpressionVisitor.VisitConditional(ConditionalExpression conditionalExpression)
   at System.Linq.Expressions.ConditionalExpression.Accept(ExpressionVisitor )
   at System.Linq.Expressions.ExpressionVisitor.Visit(Expression node)
   at Microsoft.EntityFrameworkCore.Query.RelationalSqlTranslatingExpressionVisitor.TranslateInternal(Expression expression)
   at Microsoft.EntityFrameworkCore.Query.RelationalSqlTranslatingExpressionVisitor.Translate(Expression expression)
   at Microsoft.EntityFrameworkCore.Query.Internal.RelationalProjectionBindingExpressionVisitor.Visit(Expression expression)
   at Microsoft.EntityFrameworkCore.Query.Internal.RelationalProjectionBindingExpressionVisitor.Translate(SelectExpression selectExpression, Expression expression)
   at Microsoft.EntityFrameworkCore.Query.RelationalQueryableMethodTranslatingExpressionVisitor.TranslateSelect(ShapedQueryExpression source, LambdaExpression selector)
   at Microsoft.EntityFrameworkCore.Query.QueryableMethodTranslatingExpressionVisitor.VisitMethodCall(MethodCallExpression methodCallExpression)
   at System.Linq.Expressions.MethodCallExpression.Accept(ExpressionVisitor )
   at System.Linq.Expressions.ExpressionVisitor.Visit(Expression node)
   at Microsoft.EntityFrameworkCore.Query.QueryCompilationContext.CreateQueryExecutor[TResult](Expression query)
   at Microsoft.EntityFrameworkCore.Storage.Database.CompileQuery[TResult](Expression query, Boolean async)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.CompileQueryCore[TResult](IDatabase database, Expression query, IModel model, Boolean async)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.<>c__DisplayClass9_0`1.<Execute>b__0()
   at Microsoft.EntityFrameworkCore.Query.Internal.CompiledQueryCache.GetOrAddQuery[TResult](Object cacheKey, Func`1 compiler)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.Execute[TResult](Expression query)
   at Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryProvider.Execute[TResult](Expression expression)
   at Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryable`1.GetEnumerator()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 )
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
[...]

I can overcome this issue by using:

TrimmingRoot.xml

<?xml version="1.0" encoding="utf-8"?>
<linker>
    <!-- Necessary for NpgSql library -->
    <assembly fullname="System.Private.CoreLib">
        <type fullname="System.Math" preserve="all" />
    </assembly>
</linker>

And in my application add this to the .csproj file:

  <ItemGroup>
    <TrimmerRootDescriptor Include="TrimmerRoots.xml" />
  </ItemGroup>

But I think your library should take of this.

[roji]

Duplicate of #26288

[roji]

@EjaYF I'll be working on EF Core trimming compatibility for EF 7.0 - though it's good to know things were working for you in 5.0.

[roji]

@EjaYF I'm looking into this, and I wanted to confirm something... Can you confirm that with .NET 5.0 - where everything was running well for you - you were getting (and ignoring) many trim analysis warning when publishing? And that your EF Core application was still running well?