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Comment by kridsdale3 | Hacker News Reader

Can those kinds of things work in monorepos with 50 million files?

They use this thing called repo map[1]. I only used it for personal projects and it’s been great. You need to add the files you care about yourself, it’ll do its best and add additional files from the repo map if needed.

Since it’s git based, it makes it very easy to keep track of the LLMs output. The agents is really well done too. I like to skip auto commit so I can “git reset —hard HEAD^1” if needed but aider has built in “undo” command too.

[1] https://aider.chat/docs/repomap.html

Thats a cool idea, kind of reminds me of ctags.

Aider had actually used ctags to implement that feature before they switched to tree-sitter.

Can you work in a repo with fifty million files? Can Git? I just checked on my Windows machine using Everything and there are 15,960,619 files total including every executable, image, datafile, &c.

Out of curiosity what does your IDE do when you do a global symbol rename in a repository with fifty million files?

I'm absolutely a real human, and I think this just might be too much context for me! Perhaps I am not general enough.

Having worked on a codebase like that, you need to use some extra plugins to get git to work. And even then, it’s very slow. Like 15-30 seconds for a git status to run even with caching. Global renames with an IDE are impossible but tools like sed and grep still work well. Usually there is a module system that maps to the org structure and you don’t venture outside of your modules or dependency modules very often.

I thought this was common knowledge but I guess not: Google's monopoly famously has over a billion files. No, Git cannot handle it. Their whole software stack is developed around this from the ground up. But they are one of the largest software employers in the world, so quite a few engineers evidently do make do with 200x more than 50 million files.

Monopoly <> Monorepo This is the funniest typo possible in the context of google

No and neither can you. Like you, it works best with small, focused context.

These tools aren’t magic. But they do certain tasks remarkably well.

> No and neither can you.

People do work on monorepos with 50 million+ files, though…

I made a tool that allows you to use LLMs on large codebases. You can select which files are relevant and embed them into the prompt: https://prompt.16x.engineer/

Based on my personal experience it works well as long as each file is not too long.

I believe they can as long as you're able to identify a contained task that touches no more than a handful of files. Still very useful to automate some tedious work or refactoring if you ask me.

That's effectively an answer of "no".

I used to work in a monorepo of that size.

All of the PRs I ever submitted touched a handful of files in my project’s subdirectory.

That's effectively an answer of "yes".

Or what "yes" looks like to you? It can do all the work itself, for a 50m-file monorepo, without a human guiding it which files to look at?

If it were true then human programmers would have been considered obsoleted today. There would be exactly zero human programmers who make any money in 2025.

It doesn't take the whole repo as context, it tries to guess which files to look at. So if you prompt with that in mind, it works well. Haven't tried it on a very large codebase though. You can also explicitly add files, if you know where work should be done.

you can make it work. just think of the many approaches and you'll see that there are actually quite many viable ways to work around pseudo-infinite context.

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