Because there will be a reason why the code was changed that introduced the bug. If you fix the bug you might inadvertently break a different piece of functionality.
A git commit gives you the reason for the change and the context of what other files were changed at the same time. I’ve found that invaluable.
I'm just going to answer this one candidly. Yes, you are doing something wrong. Immediately: the commit history is useful to understand the context in which a bug was introduced, because it's the best context to understand the _reason_ the mistake was maybe, which is a really good way to prevent regressions. But more generally: when an entire industry has arrived at an accepted practice, you the junior developer (sorry, 5 years is _nothing_: you need to be told this too) have a chance to pick up on it.
Have you heard "have you played guitar for 20 years, or have you played guitar 20 times for a year?" Time only helps with accumulating wisdom if you let it.
You can of course choose alternate strategies. It comes up a lot when doing low level systems programming because the bugs can be non-trivial to repro and root cause (particularly for C/C++ where you have segfaults and whatnot). So it’s cheaper and faster to try a bisect to find the regression introduction as an additional clue in the root cause analysis (eg ownership rules changed or there were changes that looked correct regarding threading but when you hyper focus on it you realize what the problem is). Or you’re working on a high performance codebase and there was a performance regression - it can be faster to bisect than it is to try to find the issue with profiling tools (I had this and seen issues where profiling tools would never have told you the issue).
I would ignore it if I spotted it once. This is the second time, though, so I probably should point it out: 5 years is a very short time in terms of personal experience and development. While the whole industry moves very fast, it does so thanks to slow, grinding effort parallelized over hundreds of thousands of individuals. For an organization, 5 years is an era. For individuals, it's just 3-6 projects (+/- a few, depending on the context you work in).
TL;DR: "never have encountered in 5 years" is a meaningless data point.
My professional career can legally drink beer since a few years back, yet I'm still regularly hitting "first times" on various things in my day job; I'm also frequently mind-blown reading about others' experiences in domains I never touched. Don't make those "5 years" into a badge to hide behind; use it as a springboard to reach higher.
In this case, try to actively think of uses for the commit history. It's already there; there's an expectation (admittedly, to various degrees depending on context) that it will be maintained. Try to maximize the value you get out of it. Underutilizing a tool you have access to may not be that much of a problem on average, but in some specific circumstances can make a difference between being able to complete a task at all or not. You shouldn't rely on luck to never land in a situation like that: familiarizing yourself with as many potential uses for a tool as possible gives you a better chance of handling it more easily.
It depends on the size of the project (mostly in terms of number of active developers) and how close you are to the running code in production.
On a large project it's probably the first tool I reach for when we find something we have reason to believe was a recently introduced bug. Specifically annotating (git blame) the relevant code and scanning for what lines have been recently modified.
I've worked in startups where there were only 2 backend devs and a frontend guy. There it was almost completely irrelevant and I spent a couple of years at a large software shop, early in my career, where bugs in production code was mostly someone else's problem.
Probably, because in my 20 year career I have encountered it plenty except back the first couple of years as a junior developer when I did not know my tools and did not know that I should do this.
> A git commit [ideally] gives you the reason for the change
FTFY ;) I broadly agree, but it's important to note that, in practice, Git commits are hit and miss: they might save you a lot of time if they are well-structured and described properly, but they might also completely fail to give you anything of value (for the problem you're facing at the moment). Turning Git history into a broadly useful artifact requires a lot of discipline from everyone working on a codebase over its lifetime.
It's never totally useless, but it's often less helpful than it could be.
Recently, I turned to JJ for this exact reason: crafting a meaningful change history is much easier there, especially if you need to retrofit it after you're done with the implementation. jj's split, squash, and describe are a joy to work with, also because the interactive version lets you easily split or squash hunks (selected changes in the same file).
Fair. Though I find it works well when commits get squished at the PR level. That way you have a link to a (hopefully!) detailed overview of what happened, when and why.
Concrete example: yabridge is a tool to let Linux users run DAW plugins designed for Windows. Some changes to Wine (yabridge's main dependency) made yabridge stop working in 2024, and those Wine changes are not going to be undone as they advance progress on Wine's own bug list and test suite. When those changes were made, there wasn't a clear way to change the yabridge code to work with the modified Wine functions.
At the very least, if Wine and yabridge didn't keep a history of their code, you wouldn't even be able to download and build Wine 9.21 staging, when yabridge worked.
Every few weeks, a new dev will find this problem and look into fixing it. By having a history, this dev can always look back on the working implementation. Maybe one day there will be a series of function calls in the new Wine codebase that gets the same behavior that worked before? Maybe Wine adds a flag for yabridge that reintroduces the old functionality but retains for everyone else the changes they decided were necessary. Both avenues would fix the bug but from different ends.
(I understand Wine avoiding the flag solution: It's more to maintain just to help a single project, plus it introduces a conditional jump fail in the very active event handler and windowing subsystems affecting nearly every Wine user, and the development of Wine keeps moving, which could make a flag-based workaround redundant in the near future.)
I haven't opened my DAW in a few months. Last I knew, the problem is resolved for most users but not all, and there might have been a major breakthrough in April or May that still hasn't reached end users.
I don’t - Windows keeps a compatibility database for a reason. It seems inevitable that you’d need to maintain that too to keep apps working or drop support. The performance is a non-sequiter for a few reasons. Even in the hot path the conditional is going to get speculated away since the wine subsystem is uniquely instantiated per application. If you were really paranoid you could ship multiple binaries and select which ones to use dynamically at runtime. I suspect the bigger problem is one of maintenance - Microsoft does this with a huge budget and a huge team whose sole responsibility is maintaining that comparability. A community project is going to have to make more pragmatic choices.
Diagnosing why a bug happened is interesting. Sometimes it points to a communication shortcoming that the project/organization should strive to improve on. Of course, if you're slinging code with a few buddies, it might not matter.
In the worst/most paranoid case (xz) you might also want to know who planted a backdoor and where else they made commits to.
A git commit gives you the reason for the change and the context of what other files were changed at the same time. I’ve found that invaluable.