EF Issue Triage

This skill covers triaging and reproducing incoming issues on the Entity Framework Core repository. To do so, read the issue in question (provided as input in the prompt), as well as any linked issues/code/resources, apply appropriate classifications and assignments, and for alleged bugs, try to arrive at a minimal repro. User-submitted bug reports frequently provide only fragmentary information and code snippets, forcing you to try to fill in the missing information in the effort to create a minimal repro; valuable information is frequently provided in free-form text, which you need to integrate into the repro as code.

High-level steps

1. Read the issue in question and any linked issues/code/resources.
2. Assess whether the issue involves any sort of security concern. If it does, either because the reporting user claims so, or because you suspect there might be a security aspect that the reporting user hasn't mentioned, exit immediately. Do not continue processing or post anything on issues which may involve any sort of security aspect.
3. Determine whether the issue is a feature or bug, and set the GitHub issue type accordingly.
4. Determine what area of EF the issue relates to, and apply area labels to the GitHub issue accordingly (see below for more details).
5. Produce a minimal repro
   1. If the issue was determined to be a feature request, skip the minimal repro in this step; continue with the remaining triage steps (duplicate search and final report).
   2. If, on the other hand, the issue was determined to be a bug report, attempt to produce a minimal repro as a console program which confirms that the bug is genuine. See "Creating a minimal repro" below for instructions.
   3. If you've managed to confirm a bug in your repro, test your repro on both the failing version and the previous working version. Provide clear feedback confirming or refuting the fact that the reported issue is a regression.
6. Try to find possible duplicate issues - opened or closed - in the EF Core repo (https://github.com/dotnet/efcore), and include the likely candidates in your final report.
7. Post your final report as a comment on the issue being triaged.

Area labels

The EF repo contains a set of "area" labels that express which part of EF is affected. Area labels always start with an area- prefix. You can see the canonical list of area labels at https://github.com/dotnet/efcore/labels?q=area-, or fetch them using the GitHub CLI with gh label list --search "area-" --repo dotnet/efcore.

• If an issue affects only a specific provider, make sure to add the label corresponding to that provider (e.g. area-sqlserver, area-cosmos...). However, if an issue affects all providers, do not add provider labels.
• The same issue can have multiple labels when relevant. For example, a Cosmos query bug should have both area-cosmos and area-query.

Creating a minimal repro

The minimal repro should be created as a completely separate console program, outside of the EF repo. Use the following as your starting point:

using System;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;

await using var context = new TestContext();
await context.Database.EnsureDeletedAsync();
await context.Database.EnsureCreatedAsync();

public class TestContext : DbContext
{
    public DbSet<Blog> Blogs { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        => optionsBuilder
            // Modify the following line to switch EF providers
            .UseSqlServer(Environment.GetEnvironmentVariable("Test__SqlServer__DefaultConnection"))
            .LogTo(Console.WriteLine, LogLevel.Information)
            .EnableSensitiveDataLogging();

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
    }
}

public class Blog
{
    public int Id { get; set; }
    public string Name { get; set; }
}

• Try to integrate the user's code into the minimal template, incorporating any textual instructions from the issue, or clues that you can glean.
• At the end of the process, the minimal repro should compile and execute, and reproduce the user's reported error.
• The program should use code that's as close as possible to the user-reported code, including type/property naming and things that seem irrelevant.

Database providers used in the bug report and repro

• We're ideally looking for a repro using SQL Server (or, as a fallback, using SQLite), which are the built-in EF providers; these are easiest to investigate and reproduce. So reproducing on SQL Server should be your starting point.
• However, if the bug isn't immediately reproducible on SQL Server/SQLite, it may require a different database; check the issue report for the reported database, or try to infer from the textual description what database the user is using. Then, attempt to reproduce the bug on that database. If you've managed to repro a problem on a provider other than SQL Server, please attempt to port the repro back to SQL Server, as that's the easiest built-in provider to diagnose/debug on. When doing this, you need to see the same error/exception on SQL Server as on the non-SQL Server provider, otherwise that may be showing a different issue. This would also confirm whether the bug is specific to e.g. the PostgreSQL provider, or a general EF Core bug.
• Some databases (PostgreSQL, MySQL) should already be installed on the github runner image which you're running - but you may still need to bring them up. Others may require bringing in a testcontainer to run the repro against.
• Pay attention to the EF provider version being used, as the bug may be specific to the version reported by the user. Once you have a working repro, try other, newer versions to confirm where the bug still occurs, and whether it has already been fixed.
• Once you've pinned down a provider to repro on (ideally SQL Server), do not keep code for multiple providers - the repro should only have code to repro on a single provider.

Make the repro as minimal as possible

Once you've managed to reproduce the bug, work to make the repro as minimal as possible, removing any code that isn't absolutely necessary to triggering the bug:

• If the repro includes a LINQ query, try to remove any irrelevant LINQ operators from that query, as long as the error continues to reproduce.
• If the repro makes use of AutoMapper, attempt to remove it, reproducing the raw LINQ query which Automapper produces.
• If the repro is a query translation issue and does not actually require seed data to reproduce, remove any seeding as well, keeping only the query.
• Do not include any non-necessary Console.WriteLine, banners, comments, summaries or other long-form text inside the code to explain what's going on. Add minimal one-line comments at most, and only where they're really necessary to follow a complicated flow or document results of calls; otherwise no comments are necessary.
• Do not encapsulate code in functions unless really necessary - prefer a simple, minimal function-less program with only top-level statements.
• Do not catch exceptions in order to convert them to a friendlier message; just allow them to bubble up and terminate the program.
• However, leave the LogTo code that ensures that SQL gets logged to the console for diagnostics.
• Do DbContext configuration within the OnConfiguring method of the DbContext type, rather than building the options externally and passing them to the constructor. Avoid any sort of DI unless it's necessary to reproducing the bug.
• In general, the less lines of code, the better.

Posting your findings

• Post your findings on the triaged issue as a comment.
• The comment should begin with a first-level heading with the text "AI Triage", followed by the sentence "The below is an AI-generated analysis and may contain inaccuracies."
• If there's a minimal repro, its source code should be contained within the posted comment, wrapped inside a collapsible HTML <details> block, to not take up too much space (the summary should be "minimal repro").
• In your response, make sure that all links to issues, pull requests or source files are to the repo on github.com, and not local (e.g. file:// or vscode://) links, as your answer will be posted online.