The Go Command That Kills AI Slop

Added: 2026-05-07

[00:00:00]Did you know there is a command in Go that can clean up your legacy code? This is very useful when working with AI because AI can produce messy and outdated code. Here we have an example and we have a volume control struct and then we have a method called set level and in this method we want to do some validation. So you cannot set the volume level to be below zero and you cannot set it to be above 100. And while this code works, there is a newer way how to do this. With Go 1.21, min and max functions were added. So instead of fixing this manually, what you could do instead is run a command. If I open up my terminal and here I can run go fix and after I run it, we can see one if statement was replaced with max. Now, if I run it again, go fix, we can then see the second if statement was removed and replaced with the min function. And the reason you have to run it multiple times is because go fix only see the original code. However, the first time when you run it, it might create a pattern that another fix could clean up. And if you would like to know what else does go fix, I created a blog post here where I go through all the examples that go fix will clean up. There will be a link in the description. Another useful thing you can use go fix for is, let's say we have some kind of library. This can be a library that's maybe shared externally or it could be a library that you share internally with the rest of your code.

[00:01:36]It doesn't really matter. So here we have a delete function and it will delete a file on the file system. But then let's say our business requirements changes and instead of deleting, you want to archive this file. So it might look something like this. We will have a new function called archive and for this case, we will upload it to S3 and if it was successful, we will then delete the local file. And then after implementing this new archive function, you might say, "Okay, but this is easy. We used replace where we call delete with archive." But the problem with that is if this was a library, then you have no control over who will be calling this function. What you then could do is you could mark this delete function as deprecated. To do that, you add the deprecated comment and when a developer try to use this function, it will say that it's deprecated. And then if we open up main.go here and we try to call it, so we will say storage and then we will say delete. And we can now see it says storage delete is deprecated. Now, the problem with this is maybe the business requirements are very strict and we must always keep a copy of the local file we delete. How would you fix that? If we go back to the storage file, you could then say, "Oh, but this is easy. We remove this code and we replace that by calling archive inside delete.

[00:03:03]So this would work. However, there is a problem with this approach. If we go back to main.go, you can imagine that you have this call in a lot of places and yes, it would show up as deprecated.

[00:03:17]But the big problem with this is it's no longer a delete function, it's a archive function. So developer using this would be very confusing. They would just think it deletes it, but actually we are keeping a copy of the file. So how could we solve this? If we go back to the storage file, go fix has a comment that you can use and it will look something like this. So I paste it here and then we say go fix inline. And let's go back to our main.go and let's pass this some file.

[00:03:49]txt and let's see what happened now when we run go fix.

[00:03:54]We can then see that it replaced the deprecated delete function with archive.

[00:04:00]And now it also makes sense for another developer that is reading the code. If this was a library and someone was using it, when they would run go fix, it would automatically get these updates. Do you want to become a senior Go engineer?

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