Ask HN: How do you deal with 2000 line functions?

#1

Post by pinkunicorn » Tue, Jan 19, 2016, 5:43 PM UTC

I'm working with an archaic code base and I'm stuck at trying to add new business logic into a 2000 line function that is absolutely crappily written with nothing but if() conditions in it. Given such a scenario, how do I go about adding a new functionality to this mess? Should I tell my manager that the function needs to be refactored and take time to refactor it?

Edit: Removed offensive word

Re: Ask HN: How do you deal with 2000 line functions?

#2

Post by PaulHoule » Tue, Jan 19, 2016, 5:51 PM UTC

Yes, just don't use the word "shit".

The obvious refactoring is to split the function up into smaller pieces, even if you can split it into two 1500 line functions that is a win.

Re: Ask HN: How do you deal with 2000 line functions?

#3

Post by sharemywin » Tue, Jan 19, 2016, 5:52 PM UTC

you probably need a ton of unit tests for this thing.

Re: Ask HN: How do you deal with 2000 line functions?

#4

Post by mod » Tue, Jan 19, 2016, 5:53 PM UTC

You test the shit out of it, then re-write it ensuring tests pass, then add your new code.

It's probably easier to do that than to muck around in the 2000-line version hoping you don't screw something else up.

Re: Ask HN: How do you deal with 2000 line functions?

#5

Post by pinkunicorn » Tue, Jan 19, 2016, 5:54 PM UTC

PaulHoule wrote: post #2

Yes, just don't use the word "shit". The obvious refactoring is to split the function up into smaller pieces, even if you can split it into two 1500 line functions that is a win.

Thanks, that came out of frustration from looking at similar long-sized functions for an extended period of time.

Re: Ask HN: How do you deal with 2000 line functions?

#6

Post by pinkunicorn » Tue, Jan 19, 2016, 5:55 PM UTC

mod wrote: post #4

You test the shit out of it, then re-write it ensuring tests pass, then add your new code. It's probably easier to do that than to muck around in the 2000-line version hoping you don't screw something else up.

Makes sense. So step #1, get 100% coverage for that thing.

Re: Ask HN: How do you deal with 2000 line functions?

#7

Post by josephmx » Tue, Jan 19, 2016, 6:00 PM UTC

PaulHoule wrote: post #2

Yes, just don't use the word "shit". The obvious refactoring is to split the function up into smaller pieces, even if you can split it into two 1500 line functions that is a win.

Is swearing on HN banned now?

Re: Ask HN: How do you deal with 2000 line functions?

#8

Post by NDizzle » Tue, Jan 19, 2016, 6:02 PM UTC

mod wrote: post #4

You test the shit out of it, then re-write it ensuring tests pass, then add your new code. It's probably easier to do that than to muck around in the 2000-line version hoping you don't screw something else up.

Yep, this is the only way to handle these beasts. Don't touch anything. Make a ton of tests. Spend some time validating those tests. Get someone to write off that those tests are sufficient. Start refactoring!

Re: Ask HN: How do you deal with 2000 line functions?

#9

Post by s73v3r » Tue, Jan 19, 2016, 6:05 PM UTC

Unless it's going to take a really long time, don't tell the boss it needs to be refactored; just do it.

Re: Ask HN: How do you deal with 2000 line functions?

#10

Post by there4 » Tue, Jan 19, 2016, 6:07 PM UTC

This is a great presentation about refactoring that may be useful: "RailsConf 2014 - All the Little Things by Sandi Metz" https://www.youtube.com/watch?v=8bZh5LMaSmE