Investigate Hot Reload issues with EF Core

I’ve ported my project from v5 to v6 EF Core. Previously everything worked fine but now I’m getting random translation exceptions from EF.Functions.Like calls. I monitor the same operation and see the same data coming from input but sometimes it passes fine and sometimes throws an exception.

Behavior looks random, I can’t understand what’s causing it. But I see it is a cascade failure. Once one error pops, all queries with LIKE function starts to fail on execution: different tables, not a single one.

Call example:

public static async Task SetCacheLastAccess(string id, string type)
{
   await using var db = new DbContext();
   var entry = await db.Cache.FirstOrDefaultAsync(a => EF.Functions.Like(a.Id, id) && EF.Functions.Like(a.Type, type));
}

...
       public string Type { get; set; } = "-";
        public string Id { get; set; }
...

Database

            modelBuilder.Entity<ThdCacheEntry>().HasIndex(u => u.Id);

            modelBuilder.Entity<ThdCacheEntry>().ToTable("cache");

            modelBuilder.Entity<ThdCacheEntry>().Property(a => a.Id).HasColumnName("id");
            modelBuilder.Entity<ThdCacheEntry>().Property(a => a.Type).HasColumnName("type");
            modelBuilder.Entity<ThdCacheEntry>().Property(a => a.LastAccess).HasColumnName("lastAccess");
            modelBuilder.Entity<ThdCacheEntry>().Property(a => a.LastUpdate).HasColumnName("lastUpdate");
            modelBuilder.Entity<ThdCacheEntry>().Property(a => a.Content).HasColumnName("text");
            modelBuilder.Entity<ThdCacheEntry>().Property(a => a.Days).HasColumnName("days");

Exception details

The LINQ expression 'DbSet<ThdCacheEntry>()
    .Where(t => __Functions_0
        .Like(
            matchExpression: t.Id, 
            pattern: __id_1) && __Functions_0
        .Like(
            matchExpression: t.Type, 
            pattern: __type_2))' could not be translated. Additional information: Translation of method 'Microsoft.EntityFrameworkCore.DbFunctionsExtensions.Like' failed. If this method can be mapped to your custom function, see https://go.microsoft.com/fwlink/?linkid=2132413 for more information.
Translation of method 'Microsoft.EntityFrameworkCore.DbFunctionsExtensions.Like' failed. If this method can be mapped to your custom function, see https://go.microsoft.com/fwlink/?linkid=2132413 for more information. Either rewrite the query in a form that can be translated, or switch to client evaluation explicitly by inserting a call to 'AsEnumerable', 'AsAsyncEnumerable', 'ToList', or 'ToListAsync'. See https://go.microsoft.com/fwlink/?linkid=2101038 for more information.

   at Microsoft.EntityFrameworkCore.Query.QueryableMethodTranslatingExpressionVisitor.<VisitMethodCall>g__CheckTranslated|15_0(ShapedQueryExpression translated, <>c__DisplayClass15_0& )
   at Microsoft.EntityFrameworkCore.Query.QueryableMethodTranslatingExpressionVisitor.VisitMethodCall(MethodCallExpression methodCallExpression)
   at Microsoft.EntityFrameworkCore.Query.QueryableMethodTranslatingExpressionVisitor.VisitMethodCall(MethodCallExpression methodCallExpression)
   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__DisplayClass12_0`1.<ExecuteAsync>b__0()
   at Microsoft.EntityFrameworkCore.Query.Internal.CompiledQueryCache.GetOrAddQuery[TResult](Object cacheKey, Func`1 compiler)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.ExecuteAsync[TResult](Expression query, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryProvider.ExecuteAsync[TResult](Expression expression, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.ExecuteAsync[TSource,TResult](MethodInfo operatorMethodInfo, IQueryable`1 source, Expression expression, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.ExecuteAsync[TSource,TResult](MethodInfo operatorMethodInfo, IQueryable`1 source, LambdaExpression expression, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.FirstOrDefaultAsync[TSource](IQueryable`1 source, Expression`1 predicate, CancellationToken cancellationToken)
   at ThunderED.DbHelper.<SetCacheLastAccess>d__35.MoveNext() in 

Include provider and version information

EF Core version: 6.0.0 Database provider: Microsoft.EntityFrameworkCore.Sqlite 6.0.0 Target framework: .NET 6.0 Operating system: WIn10 x64 21H1 IDE: Visual Studio 2022 17.0.2 Project: Blazor Server-Side

[panthernet]

UPDATE: Okay not sure by 100% but looks like it happens after I use HOT RELOAD button in VS 2022 to apply changes OR reload happens automatically on code change. I use server-side Blazor for the project.

UPDATE: Confirmed. HOT RELOAD is the bad guy.

HOT RELOAD logs

THDWebServer (Web server): Hot reload session complete
THDWebServer (Web server): Hot reload session started
THDWebServer (Web server): Sending updates to running application
THDWebServer (Web server): Updates applied successfully

[rshekhtm]

Same issue with hot reload and EF.Functions.ILike usage. The hacky workaround I put in place was to catch the InvalidOperationException and invoke a query without ILike that is similar enough for development purposes, but is not suitable for production.