5 ms·
All means are fair except solving the problem
- PaulHoule 6mo agoAren't you supposed to return a 0 status code when "yea done!" and some other status code when it wasn't done?
- yosefk 6mo agoIndeed you're supposed to, but that way if someone calls exit(0), it looks like the program worked fine, when in fact they committed some debug code and made the program no longer run to completion. "Yay, done" was put in for the scripts to flag this sort of thing, presumably based on experience.
- PaulHoule 6mo agoI can say up until 2005 or so I was a real believer in printf() debugging but I deliberately switched to using a debugger as much as possible around that time. I found that no matter how hard people "try" if they modifying the code to do debugging there is some chance these get checked in -- whereas you can investigate many things with the debugger without checking anything it. Some applications have more trouble with setup and teardown than others. Like I knew a professor who kept sending me C programs that would crash before main() and some systems have a lot of trouble with "crash on shutdown" which might be a problem (corrupted files) or a non-problem.
- anyfoo 5mo agoJust make it fprintf(stderr, ...) debugging instead.
- XorNot 5mo agoWe still seem to have fairly bad tooling for advanced debugging use cases. There's no good reason you shouldn't be able to have an IDE maintain a text overlay of debugging points which is solely supplied as breakpoint scripts to the debugger instead. IDEs seem to conk out at click to set breakpoint.
- bitwize 5mo agoThat has literally been table stakes for Windows development since the 90s. Not having the debugger fully integrated into your integrated development environment is strictly a problem of the commercial Unix and open source crowd and their "Real Programmers are fine with stone knives and bearskins" machismo.
- quietbritishjim 5mo ago> I was a real believer in printf() debugging but I deliberately switched to using a debugger This really does not need to be an either/or. They have different uses. You can stick in 20 printfs and get a quick feel for where the bug is far quicker than stepping through the code - especially if you set a breakpoint and hit run, only to realise that you've overshot. You can run the program 10 times with different parameters and compare the results with printf much more easily than you could with a debugger. But, once you've found the rough area, a debugger is much better for fine grained inspection, and especially interrogating state with carefully written watches. I do get your point about the risk of leaving in some trace by accident. But it feels like overkill to throw away such a valuable tool just because of that.
- PaulHoule 5mo agoI'll do printf() debugging as a second line or when the debugger isn't convenient. But i do reach for the debugger first.
- kubb 5mo ago"People deliberately misuse the very mechanism that was designed to indicate successful completion, so we added another, flawed detection mechanism based on IO, because there's no way they'll do the thing that they should have learned in the first year of school, and just call exit with any other argument than 0 on irregular completion". Gosh I thought the engineering culture was bad where I work.
- roughly 5mo agoBrother, have I got bad news for you about all the places outside your door.
- ryandrake 5mo agoYea, whatever you do, don't solve the actual problem! This reminds me of solving a buffer overflow by just blindly increasing the size of the buffer until it no longer crashes.
- hackable_sand 5mo agoThe amount of problems I have handled with liberal void* is greater than I care to admit
- anyfoo 5mo agoThen that's utterly and horribly wrong? And in my decades of experience, I've fortunately only relatively rarely had to deal with that particular kind of atrocity.
- atmavatar 5mo agoNext thing you know, you'll have to skip a major version number in your product because a significant fraction of your user base string parse its name to determine what version it is.
- hiAndrewQuinn 5mo agoThere is a parallel universe where the convention is that 0 is used for when something went wrong, and 1-127 are reserved for all the myriad and beautiful ways in which things went right.
- linkregister 5mo agoIt's POSIX convention to write to stderr for anything that's not strict program output. I have seen 2>&1 far too often in scripts. I don't worry about it and happily write error messages to stderr whenever my scripts exit without a 0 status code.
- ryandrake 5mo agoAnother thing that gets screwed up a lot is: Comand line usage help/information should be printed to stderr if it was invoked because the user passed an invalid option to the command line (in other words, the usage text counts as diagnostic[1] info), but it should be printed to stdout if the user invoked the application with -h, --help or similar. Reasons: 1. If you mess up the command line to the program in a script or pipe, and get a bunch of usage output in stdout, a downstream consumer of that stdout might think its legit program output and try to parse it. 2. If your user actually calls the program with -h or --help, they might want to |less through it to read it on a small terminal screen. Output that to stdout. 3. Generally, you can always tell if something is going wrong by grepping for errors or warnings a single stream (stderr), or by looking for a nonzero exit code. But your general principle applies: Output expected by the user -> stdout. Diagnostic output or output incidental to the program's operation or errors -> stderr. 1: https://pubs.opengroup.org/onlinepubs/9799919799/functions/stdin.html https://pubs.opengroup.org/onlinepubs/9799919799/functions/s...
- anyfoo 5mo agoDisagree. stdout is only reserved for actual processed command output. It may be empty, it may be invalid because the input was invalid (shit in, shit out), but it may never be things intended for a human to read. If one wants to use a pager (like I sometimes do, though most of the time I just scroll up), they'll just use `foo 2>&1 | less`.
- ryandrake 5mo agoGNU offers guidance[1] to output --help to stdout, but it's not against the law to do it your way. 1: https://www.gnu.org/prep/standards/html_node/_002d_002dhelp.html https://www.gnu.org/prep/standards/html_node/_002d_002dhelp....
- johnfn 5mo agoBut the whole idea is that a warning is a warning. Solving a warning can be deferred, and a warning doesn't cause execution to fail. Your warning was transmuting itself into an error. I feel like "All means are fair except solving the problem" is the wrong conclusion to draw here. If it should have been solved immediately, it should have been an error in the first place. (And then you should have politely bumped the version so that you don't immediately break the code of all your dependents.) If there is no need to solve it immediately, then "all means are fair" to convert it back to a warning as was originally intended.
- asdfasgasdgasdg 5mo agoThe warning was only "transmuting" itself into an error because another team took a dependency in their test on the exact ordering of writes of certain data to a globally shared resource.
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- chadgpt2 5mo agoWas this FOSS or commercial? If it's commercial software, you're paid to make it work, no matter how stupid that may be, and forced stupidity isn't your problem. If it's FOSS, you can tell the user to deal with it and close the ticket.
- debugnik 5mo agoThe other team is also paid to make the whole thing work, though. That alone is not enough reason to yield.
- potbelly83 5mo agoWhy not have the program touch a file on success?
- anyfoo 5mo agoWhy not have the program exit with exit code 0 on success, and non-0 on failure, like almost every program in a POSIX environment ever?
- potbelly83 5mo agosee yosefk reply above
- anyfoo 5mo agoI'm sorry, but "they committed some debug code that made the program exit(0)" for me is pretty much equivalent to "they committed some debug code that made the program not work correctly".
- anyfoo 5mo agoDoes no one know what exit codes and stderr vs. stdout is anymore? I work with old and new code bases used by many clients in complicated setups, but adding a warning to stderr while stdout was left untouched, and proper exit codes maintained, was hardly, if ever, a problem so far. Of course, there's always some unpleasant exception, but it's rare. And of course, I also understand that the author might have found themselves not only in one of those rare-ish instances, but also one where reasoning with the other side was fruitless.
- adrian_b 5mo agoYes, this was also exactly what I have thought while reading TFA.
- AnimalMuppet 5mo agoI worked on a code base that ran on a variety of Unixes. One customer complained about file corruption from our software. Turns out that their Unix setup was... rather unique. Spawned programs were not given a stderr file handle! If you wrote to stderr, it scribbled on whatever file was open on file handle 2. We, uh, reasoned with the other side - we told them to fix their stupid broken setup.
- anyfoo 5mo agoGlad you were able to sort it out properly. I guess maybe I'm also lucky to much less rarely work with, shall we say, consultation-resistant engineers than discussion forums sometimes make you believe.
- dylan604 5mo ago> Does no one know what exit codes and stderr vs. stdout is anymore? Sounds like you don't use ffmpeg very often. Because ffmpeg is able to send its output to stdout to be piped to other apps, verbose text output can't use stdout as one would expect. Non-error text is sent to stderr instead. So when you want to trap the text output you have to route stderr to text file. It takes some getting used to, but it's now normal for me. So, yeah, I know stderr vs stdout still, but it's not what you want it to simply be. In the real world, things are not as clean as they are in school books.
- michaelt 5mo ago> Instead, they were quick to point out that it’s hard to know where these warnings could come from, and we cannot risk all those critical workflows failing when some case of misuse surfaces in a new context. Ah yes, Schroedinger's workflow. So important any disruption is a disaster, and simultaneously so unimportant they couldn't possibly spend a single dime on the tools critical to the workflow.
- m463 5mo agoI have seen this kind of thing go so many ways. - sometimes you can get the status code, sometimes you can't. - sometimes you can separate out stdout from stderr, sometimes you can't - sometimes the program generating the error message identifies itself, sometimes it doesn't - sometimes you don't know if you have a "good error" (ok to ignore) or a "bad error" (cannot ignore) I am a fan of the HARD FAIL. I think internal unit tests or things like that should hard fail, then get a human to either fix it, or put in a hard exception. if it is user-facing... sigh
- shoo 5mo ago> I am a fan of the HARD FAIL. It reads as if the change was made to some library code that was depended upon by someone else's program that would "yay, done", which was in turn depended on by some workflow. It's probably a non-starter to change library code so it hard fails if it detects its being used incorrectly, in situations where it previously ran and did something. That's a severe breaking change in behaviour. Easing it in by printing a warning message sounds like a reasonable step toward hard failing. But then we get the situation yosefk relates.
- chr15m 5mo agoBackwards compatibility is golden.
- JanneVee 5mo agoWe even have the options around in our compilers to treat warnings as errors. As continuation on that idea I for one was lucky earlier in my career to work with the brilliant idea of just asserting in production. Straight up crash the software when something was wrong. Wrong preconditions that could mess something in the future. "empty array where it isn't supposed to be empty, sorry crash - fix your bug". even when it kind of worked, which is the real issue... it kind of works until it doesn't. I've silently introduced this mindset into my work ever since and the quality of the result is so much better. Warnings are something that will be deferred when given the option so don't warn it is an error.
- ninkendo 5mo agoOne should always imagine a 1000:1 ratio of “person who reads a warning message” to “person who can do anything about it”. You drop a little stderr print in your library saying “foo is deprecated, please use bar”, but then that library is included in another library which included in a CLI called by a script somewhere and, now the output goes to someone’s terminal when they’re running some management CLI. They never wrote the call to foo, they don’t even know what a foo is, they are 3 layers removed from who the target audience is. Runtime is never the time to alert to things like deprecations or “this shouldn’t be used this way” notices. For deprecations, use your language’s built-in way of making functions deprecated. If your language doesn’t have that, use a real programming language. For other types of warnings, if you’re not 100% sure your message will only be seen by the developer who can fix it, just don’t write it.
- moring 5mo agoBonus points for the kafkaesque responses you get as the end-user when you try to actually pass that information upstream where it could be fixed...