424: The Spectrum of Automated Processes for Your Dev Team The Bike Shed

Joël shares his experience with the dry-rb suite of gems, focusing on how he's been using contracts to validate input data. Stephanie relates to Joël's insights with her preparation for RailsConf, discussing her methods for presenting code in slides and weighing the aesthetics and functionality of different tools like VS Code and Carbon.sh. She also encounters a CI test failure that prompts her to consider the implications of enforcing specific coding standards through CI processes.


The conversation turns into a discussion on managing coding standards and tools effectively, ensuring that automated systems help rather than hinder development. Joël and Stephanie ponder the balance between enforcing strict coding standards through CI and allowing developers the flexibility to bypass specific rules when necessary, ensuring tools provide valuable feedback without becoming obstructions.



dry-rb
A broader take on parsing
Parse; don’t validate
Debugging at the boundaries
Specialized vocabulary
Carbon
RailsConf 2024
Moving errors to the left
Contracts
Linters shouldn’t be optional
Linter rules to avoid focused tests
Thoughtbot Rails guides
Danger


Transcript:


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STEPHANIE: Hello and welcome to another episode of the Bike Shed, a weekly podcast from your friends at thoughtbot about developing great software. I'm Stephanie Minn.


JOËL: And I'm Joël Quenneville. And together, we're here to share a bit of what we've learned along the way.


STEPHANIE: So, Joël, what's new in your world?


JOËL: I've been working on a project that uses the dry-rb suite of gems. And one of the things we're doing there is we're validating inputs using this concept of a contract. So, you sort of describe the shape and requirements of this, like hash of attributes that you get, and it will then tell you whether it's valid or not, along with error messages. We then want to use those to eventually build some other sort of value object type things that we use in the app. And because there's, like, failure points at multiple places that you have to track, it gets a little bit clunky.


And I got to thinking a little bit about, like, forget about the internal machinery. What is it that I would actually like to happen here? And really, what I want is to say, I've got this, like, bunch of attributes, which may or may not be correct. I want to pass them into a method, and then either get back a value object that I was hoping to construct or some kind of error.


STEPHANIE: That sounds reasonable to me.


JOËL: And then, thinking about it just a little bit longer, I was like, wait a minute, this idea of, like, unstructured input goes into a method, you get back something more structured or an error, that's kind of the broad definition of parsing. I think what I'm looking for is a parser object. And this really fits well with a style of processing popularized in the functional programming community called parse, don't validate the idea that you use a parser like this to sort of transform data from more loose to more strict values, values where you can have more assumptions.


And so, I create an object, and I can take a contract. I can take a class and say, "Attempt to take the following attributes. If they're valid according to the construct, create this classroom." And it, you know, does a bunch of error handling and some...under the hood, dry-rb does all this monad stuff. So, I handled that all inside of the obj