If you have some code that if its callers changed, they would stop using that code or use it on a different place, it's a unit and it's a good idea to unit test it. If you have some code that if its callers changed you would want to change it too, then it's on the same unit as the calling code, and it's bad to divide it away. We deploy to production multiple times per day, with no human intervention, successfully. Our test suite includes some unit and full end to end tests, and yea sometimes a breaking change slips through, we write a test to catch it next time, and move on.
Different projects have different complexities and differing levels of CD viability, but there are definitely many people truly doing automated continuous deployment all day every day. Besides less-anemic E2E tests, this is why type systems exist. Define a well-typed interface, code to the interface, test the units — and then it's hard to make terrible mistakes wiring things up. To realize the full benefit does, of course, require substantially better data structures than string-to-Any hashes, and it requires some proper old-school software engineering i.
And there is some overhead, though I'd say that a proper null-checking pass alone would be worth that much. Sorry, Java, your types are terrible. It works very well if you can tolerate that some of your users will have typically minor issues once in a while. Maybe I'm missing something but when did continuous delivery imply no human testing?
My last two jobs have had what I understand to be continuous delivery, to great success, but perhaps it was something other than CD. I don't agree that you can take humans out of the equation, particularly for new code. FANG push changes to each of many components daily, with feature flags. Trunk based can be sort of ok of you can accept a broken trunk and features can be kept small enough to give meaningful commits.
You need to make each step of each feature shippable if you use CD - so e. I make a point never to commit broken code anyway. If a series of changes have to be together to not break, I put them all in one commit. Often a feature is made up of a series of non-breaking changes that can be layered one at a time, if appropriate. As a reviewer I really want a series of commits each making closely related changes that are easy to understand.
How about with multiple repos, across multiple systems? You can't get them all in one commit then. Even with a monorepo not contributing back to upstream it'd be an utterly massive commit. That negates one of the major advantages of committing code, which is having a regular backup of your work.
My team makes several commits locally, then rebases, squashes, and pushes the squashed commit to the trunk which has CI. This maintains a local, regular backup of your code and collects features into single commits for the trunk which are easily revertable if found to be problematic. Edit: Rereading your comment, I suspect you mean non-local backups. Our organization has a special remote only visible to you and those you allow for pushing code you'd like to backup off of your box.
That sounds like feature branches but with more steps and worse. You can't share your unfinished work non-locally, for one thing.
And it has none of the advantages of CI because you still have infrequent large merges. I'm sorry but it hurts just to read this. Just No. Please could you expand?
Going back through history to find where a bug was introduced usually happens on the commit level e. Once you find the commit that introduced the bug in question, it will be immensely easier to hunt down the bug within the commit if the commit is 10 or 50 lines long instead of or MarkSweep 4 months ago parent prev next [—].
Feature flags can be helpful here. Another thing that can help is a source control system that supports multiple commits and committing them to the main branch as a contiguous unit. I believe Phabricator supports that. The next best thing you can do with GitHub is make your pretty series of commits for review, but then squash on completion using the GitHub UI.
More or less. I'm inclined to agree. More than once, I've been burned when merging a long-lived feature branch, because it turns out that, during development, the behavior of some other portion of the system changed in a way that broke the behavior of what I was working on, without actually causing any compile-time or run-time errors. You can theoretically guard against that with more and more automated testing, but that's putting a lot of weight on a thing that's almost always full of things you forgot to test, or didn't think you needed to test.
I've had better luck with feature flags. They don't take anything away from automated tests or static analysis. They potentially add a little bit more hassle in the form of maintaining the flags.
Not nearly as much hassle as sorting out a merge conflict, though. The other, quite compelling, thing they add is a much wider expanse of time during which you can notice, "Huh, that's funny," when you're doing your mid-development ad-hoc testing.
You can, of course, get a similar benefit by making a daily practice of rebasing your feature branch onto the latest version of the main branch. But my experience has been that doing that is annoying, and the thing about annoying things that you have to actively remember to do is that it's surprisingly easy to just not remember to do them. Always be merging to master or main. Feature flags make functional overlap and branching explicit and prevent difficult merge conflicts. I understand it that way as well.
Unfortunately if everyone isn't sufficiently disciplined on a team, what happens is that code that takes weeks to develop sits on their machine for weeks. Which is like a feature branch that nobody can see.
That, plus a few sentences later: "Frankly, at the time, I did not understand much about branching strategies. It all seemed too complicated to me. I had hard times trying to fit the workflow in my head. Coming next week - a post about why X is the best programming language, from someone who hasn't bothered to learn any other programming languages! Having worked with novice developers very recently I agree with the author here. The workflow of SVN and similar is much easier to understand and explain to folks who haven't used version control before.
I often find even a simple workflow involves teaching multiple Git concepts that get in the way. I don't get how that's so complicated to be honest and your host of commands is literally 3. SVN had 2, big deal, especially when of those 2, commit can destroy all your work easily n SVN, while a very simple rule of git will allow you to never loose any work: Before you do "anything else", commit! Are you insane! All of my last few new hires juniors can work without problems with our simple git workflow.
Master is always green and deployable hourly. The branch is yours to do with whatever you want until you want to actually merge to master, at which point you have to squash and rebase from master.
Some guys got bitten by not following the simple rules of "do one thing at a time" and "commit first". Luckily git refuses many actions if you have a dirty tree but people can get confused because they never read error messages. Do one thing at a time works for most things in life and software development and rebasing from master while also squashing at the same time is just insane.
Just do one of them first. Usually I find squashing first is easier as otherwise you might have to solve conflicts on intermediary commits that you wouldn't have in the first place with your squashed commit. You don't have to convince me that the git workflow is more powerful and affords more opportunities to recover from error - I completely agree and could go on at length. However, the git workflow requires you to understand a larger number of concepts and I can personally attest that these concepts are not intuitive to new learners.
For example, in Git you need to do the following, just to create a PR editing a file: 1. Checkout master 2. Pull master 3. Create a new branch off of master 4. Edit files 5. Stage edits 6. Commit 7. Push the local branch to the remote Consider the equivalent SVN workflow: 1. There's no branches, no division between local and remote, no index and distinction between staged and unstaged changes.
All of these concepts are like an unexpected speed bump when someone is trying to learn to accomplish a task; they're trying to do one thing at a time and are forced to instead learn 5 other things until those are fully reinforced. And we haven't even gotten into the various minutia of commit-squashing etiquette, rebasing vs. Not a fair comparison. You're comparing a branching workflow in Git to a branchless workflow in SVN.
The branchless workflow in Git eliminates step 1 and 3. You are fogetting something in your three step svn tutorial: svn add! You have to learn that git is always offline and you do need to actively push your commit.
Now if you were using SVN with a code review workflow, it is very likely that you used something like Atlassian's Crucible and you would use branches.
So on svn you have trunk checked out and on git you are on master. You push, big deal, already learned. But I can totally understand why a newbie might not want to. Now if we get away from the command line and just think in concepts that someone has to understand on top of svn while using a GUI, there really isn't much more than the "You need to push to actually publish your changes instead of commit always talking to the server right away".
Now we're actually at a problematic stage. At his peak, he was deploying to production fifty times an hour. Good practice not as a nice-to-have, but out of necessity! The key to both of these cases, though, is that they involve, respectively, throw-away and short-lived branches that are automatically merged into trunk. Of course, for most teams including the ones I am part of!
But we can embrace trunk-based development as a desirable goal and reconsider our use of branch-based approaches that build delay and manual bottlenecks into our flow to production. That way, we can get back to focusing on what it would take to build a system and process that will allow us to deliver code as quickly and safely as we can.
So go on, ask yourself: what would your team need to do to be able to develop safely on trunk? For more insights on implementing unambiguous code requirements, Continuous Delivery anti-patterns, best practices for microservices and containers, and more, get your free copy of the new DZone Guide to DevOps! Continuous Delivery Anti-Patterns. Better Code for Better Requirements. Executive Insights on the State of DevOps. Microservices and Docker at Scale. Thanks for visiting DZone today,.
Edit Profile. Sign Out View Profile. Over 2 million developers have joined DZone. Branching Considered Harmful! Branch-based development can be a good trade-off in some scenarios but should be considered harmful for true CI. Branches can also be useful in trunk-based environments. Better to reduce the branch instructions you use, right? I am implementing a Forth system in bit Intel assembly language. It is a silly project, but it keeps me happy and implementing it gives me a few very geeky anecdotes.
One of these anecdotes is eliminating branches from the implemention of ABS. ABS is a procedure that computes the absolute value of a number. In the version I am implementing, the input is a signed bit integer, and the output is the positive integer with the same magnitude. The first version I implement is on github. Having executed test rax, rax , the jns instruction Jumps if Not Signed. In this case Signed means "has the sign bit set" which means negative; So if rax is 0 or positive the jump is taken and so the neg rax instruction is skipped.
The new version is also on github. In the first comment, "Forth boolean" means a value that is either 0 or And while it is true that the carry flag is converted, first the sign flag is shifted into the carry flag. The new implementation is in two parts: 1. The "Subtract with Borrow" instruction computes Rd - Rs - B where Rd is the destination register, Rs is a source register, and B is the borrow aka carry flag which is either 0 or 1.
In sbb rcx, rcx the source and destination are the same: the value computed is Rd - Rd - B , which is the same as - B.
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