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I don't think the things you listed, even when combined, are sufficient substitutes for well-written documentation. The fact of the matter is that, for humans,

I don't think the things you listed, even when combined, are sufficient substitutes for well-written documentation. The fact of the matter is that, for humans, plain English is always much easier to understand than computer code. The more complex the code, the more true that is going to be. You can use all the friendly function names and object names and file layouts you want. At the end of the day, it is not going to be enough for someone who is not familiar with that part of the system to understand it quickly and to the appropriate level of detail. This is especially true if you have junior-level or intermediate-level people on your team. It is also true if you ever end up coming back to some piece of code you yourself wrote a year ago. Furthermore, documentation can provide additional value by including examples of code usage in different settings that you may not have covered in your test cases due to not being immediately relevant. It can contain links to other websites and have embedded images of system diagrams or data flow. It can also describe third-party systems your code has to interact with and various bugs and unconventional behavior that may exist in those systems that your code has to account for. Yes, documentation involves more upfront effort. IMO the correct way to deal with that is to include that in project estimates, and to not mark tasks and features to be "done" until their documentation is written. Same with revisions and bug fixes. I understand the feeling that it duplicates logic already expressed in the code. But look at it this way: code is for computers. Documentation is for humans.

wpietri 9y ago
I should be clear that I like good documentation, and will happily write it when necessary. It's just that over the years, I've a) found a lot of ways to make it unnecessary, b) grown to despise useless or out of date docs, which is the bulk of what I see, and c) grown very tired of writing documentation that people end up not reading. > [...] plain English is always much easier to understand than computer code [...] This is especially true if you have junior-level or intermediate-level people on your team. This is why I'm a big fan of collective code ownership, pair programming, and frequent pair rotation. That has a variety of benefits. It also has substantial advantages over documentation. A big piece of which is that the need for documentation is always speculative, whereas answering a question always works from a confirmed need. > It is also true if you ever end up coming back to some piece of code you yourself wrote a year ago. This is what I use tests and journals for. Well-written tests are essentially machine-verifiable documentation. They tell me what the intent of the system is. If I want to know the history of the intent, then I turn to my journals. > But look at it this way: code is for computers. Documentation is for humans. I couldn't disagree more. As Martin Fowler says: “Any fool can write code that a computer can understand. Good programmers write code that humans can understand.” Code and tests are primarily means of communication between developers. They have the constraint that they should result in a running system. But we stuff most of the work of that into compilers, optimizers, and run times. Our tools are -- and should be -- optimized for human productivity. And since programming is mostly a team sport, the biggest value of our tools is in how they enable that teamwork.
- ethbro 9y ago
  The biggest value in documentation to me has always been efficiency in understanding: that usually means documenting at the architecture / "components as black boxes" level. I could trace through to see how someone glued something together without having a hint what I'm looking for, or I could get the architecture gist and then generally know where the thing I should be looking at is. To me, this delivers two benefits. (1) Reduced redundancy / potential for divergence (as you mentioned above), as you're not re-documenting code but rather documenting at a higher level. (2) Reduced churn, as architecture changes more slowly than code, and generally an arch change will have some organizational process before being made (where docs can be updated). Disclaimer: This is coming from a place of diving into a lot of client systems with really poor or utterly lacking documentation.
  - wpietri 9y ago
    Sure, but no documentation here will be as efficient as an expert having a conversation with you and answering your questions. I'd much rather have a few whiteboard conversations and maybe some pair programming time, and that is cheaper and easier for everybody then speculative production of documentation. If the choices are only "shitty code with no docs" and "shitty code with good docs", I'll definitely take the latter. And if I'm rolling a team off a project, I'm happy to take some time to write some high-level docs for the people who will next pick it up. That's a one-time expense with documentation written for a defined audience. But when I'm picking up a system and the original team is gone, I'd much rather have good code and good tests over good docs. And honestly, I'm not sure I've even inherited a system with good docs. I have seen things that managers probably thought were good docs. And I've seen things that the developers intended to be good docs, and might have even been good once upon a time. But by the time I get to them, it's either the "we were told to write docs" garbage that is useless, or stuff that's so far out of date that it's just as often misleading as helpful.

wpietri 9y ago

I should be clear that I like good documentation, and will happily write it when necessary. It's just that over the years, I've a) found a lot of ways to make it unnecessary, b) grown to despise useless or out of date docs, which is the bulk of what I see, and c) grown very tired of writing documentation that people end up not reading. > [...] plain English is always much easier to understand than computer code [...] This is especially true if you have junior-level or intermediate-level people on your team. This is why I'm a big fan of collective code ownership, pair programming, and frequent pair rotation. That has a variety of benefits. It also has substantial advantages over documentation. A big piece of which is that the need for documentation is always speculative, whereas answering a question always works from a confirmed need. > It is also true if you ever end up coming back to some piece of code you yourself wrote a year ago. This is what I use tests and journals for. Well-written tests are essentially machine-verifiable documentation. They tell me what the intent of the system is. If I want to know the history of the intent, then I turn to my journals. > But look at it this way: code is for computers. Documentation is for humans. I couldn't disagree more. As Martin Fowler says: “Any fool can write code that a computer can understand. Good programmers write code that humans can understand.” Code and tests are primarily means of communication between developers. They have the constraint that they should result in a running system. But we stuff most of the work of that into compilers, optimizers, and run times. Our tools are -- and should be -- optimized for human productivity. And since programming is mostly a team sport, the biggest value of our tools is in how they enable that teamwork.

ethbro 9y ago
The biggest value in documentation to me has always been efficiency in understanding: that usually means documenting at the architecture / "components as black boxes" level. I could trace through to see how someone glued something together without having a hint what I'm looking for, or I could get the architecture gist and then generally know where the thing I should be looking at is. To me, this delivers two benefits. (1) Reduced redundancy / potential for divergence (as you mentioned above), as you're not re-documenting code but rather documenting at a higher level. (2) Reduced churn, as architecture changes more slowly than code, and generally an arch change will have some organizational process before being made (where docs can be updated). Disclaimer: This is coming from a place of diving into a lot of client systems with really poor or utterly lacking documentation.
- wpietri 9y ago
  Sure, but no documentation here will be as efficient as an expert having a conversation with you and answering your questions. I'd much rather have a few whiteboard conversations and maybe some pair programming time, and that is cheaper and easier for everybody then speculative production of documentation. If the choices are only "shitty code with no docs" and "shitty code with good docs", I'll definitely take the latter. And if I'm rolling a team off a project, I'm happy to take some time to write some high-level docs for the people who will next pick it up. That's a one-time expense with documentation written for a defined audience. But when I'm picking up a system and the original team is gone, I'd much rather have good code and good tests over good docs. And honestly, I'm not sure I've even inherited a system with good docs. I have seen things that managers probably thought were good docs. And I've seen things that the developers intended to be good docs, and might have even been good once upon a time. But by the time I get to them, it's either the "we were told to write docs" garbage that is useless, or stuff that's so far out of date that it's just as often misleading as helpful.