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376 points turrini | 1 comments | | HN request time: 1.006s | source
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rkharsan64 ◴[] No.42146864[source]
On a general note, I would recommend any new (and experienced!) programmers to master the debugging tools of their ecosystem. I've seen countless experienced developers use printf-based debugging and waste hourse debugging something which could've been easily figured out by setting a breakpoint and stepping through your code. This is also a good way to understand code you're unfamiliar with.

This is one area where I believe a GUI tool is so much better: I can hover over variable names to view their values, expand and collapse parts of a nested structure, edit values easily, and follow execution in the same environment I write my code in.

Sure, it doesn't help much for some scenarios (one I've heard people mention is multithreaded code, where logs are better?), but for most people it's not that far from a superpower.

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mpweiher ◴[] No.42147101[source]
Interesting.

My experience is the opposite: I see developers waste hours stepping through their code a line at a time when a few judiciously placed logs (printfs() are fine, but we can do better) would have told them exactly what they needed in a jiffy.

If you have a fairly shallow bug, that is a single point in your code that always behaves incorrectly, then I find debuggers reasonably effective.

But most of the bugs that I see aren't that shallow, with code misbehaving when the context is just so and perfectly fine otherwise. In those cases, I need to see lots of different invocations and their context. The debugger is like trying to drink the information ocean I need through a straw. A mostly plugged straw.

I wonder what makes our experiences so different? Do you unit test a lot? Particularly with TDD? I am guessing that this practice means I just don't get to see a lot of the bugs that a debugger would help me with.

(And it doesn't mean I never fire up the debugger. But it is fairly rare).

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1. a_e_k ◴[] No.42151135[source]
The big ones for me with log/printf debugging are:

- I can get a good idea of the temporal behavior of the program, and I can just scroll up to see earlier state, rather than having to restart the program in the debugger. (I know that "time travel" debuggers exist, but I've found them finicky.) I can scrub back and forth through time just by scrolling.

- I can compare runs by diffing the logs. Sometimes that alone is enough to show where things start going amiss. Or I can keep instrumented logs from baseline runs.

- If there's a personally useful set of printf statements in an area that I'm in a lot, I can save those off to a patch file or a local branch. I don't have to reapply my breakpoints / watchpoints in the debugger each time. Easy persistence.

(That said, I do like to start with a debugger when tackling reproducible crashes.)