autofac/Autofac

IStartable in a child lifetime scope causes recompilation of factory delegates

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#1,461 opened on Jul 3, 2025

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 (5 comments) (0 reactions) (0 assignees)C# (827 forks)batch import
bughelp wanted

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Description

Describe the Bug

An IStartable that depends on a Func dynamic instantiation recreates and compiles the factory delegate anew for every lifetime scope. In the Gist, FactoryGenerator.CreateGenerator is called exactly once for LifetimeWithoutStartable and a total of four times—again once, but also once per lifetime scope—in LifetimeWithStartable.

Steps to Reproduce

https://gist.github.com/Tragetaschen/0f951b32cea3aaf98c1e9b83953dfcf8

Expected Behavior

I don't see a reason why the factory delegate cannot be reused for the startable and would prefer to not pay the expression creation, compilation and native code again and again for every child scope.

Dependency Versions

Autofac: 8.3.0

Contributor guide

Research direction
Investigate the Autofac source code, specifically the LifetimeScope and FactoryGenerator classes. The gist at https://gist.github.com/Tragetaschen/0f951b32cea3aaf98c1e9b83953dfcf8 demonstrates the issue. Look at how IStartable instances are resolved within child scopes and why the factory delegate is not cached per scope. Consider whether the delegate could be compiled once and reused across scopes.
Tech stack
csharp
Domain
backendperformance
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Mostly clear
Prerequisites
C#Autofac basicsExpression trees
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
15