No, the function does return two variables, as I take out "er" from "out, err:=" go vet report a flaw: /util.go:51:9: cannot initialize 1 variables with 2 values
On Tue, Jun 10, 2025 at 10:28 AM Robert Engels <reng...@ix.netcom.com> wrote: > Just use VSCode with the standard Go plugin. > > On Jun 9, 2025, at 9:23 PM, Kurtis Rader <kra...@skepticism.us> wrote: > > > On Mon, Jun 9, 2025 at 7:01 PM Zhaoxun Yan <yan.zhao...@gmail.com> wrote: > >> Oh! Thank you Kurtis. So do you have a special Editor to inform you about >> the functions? My current editor cannot even tell what type of variable a >> go function would return, let alone parameter hints, etc. >> > > I use a VIM plugin that talks to the > https://pkg.go.dev/golang.org/x/tools/gopls tool. That makes it easy to > jump to the definition of a function or other symbol and find all the > places that use it. It is likely your editor can be configured to interact > with that tool. > > >> On Mon, Jun 9, 2025 at 1:50 PM Kurtis Rader <kra...@skepticism.us> wrote: >> >>> >>> On Sun, Jun 8, 2025 at 9:35 PM Zhaoxun Yan <yan.zhao...@gmail.com> >>> wrote: >>> >>>> it turned out to be an error misjudgement. The real line that caused >>>> trouble is this: >>>> s = er.Error()+string(out) >>>> The error is gone after I changed it to this line : >>>> s = fmt.Sprintf("%v %s", er, out) >>>> >>> >>> The stdlib os.exec.Command() >>> <https://pkg.go.dev/os/exec@go1.24.4#Command>function only returns a >>> single value. Which should result in a compiler error since your program >>> expects two values. I'm going to guess that you are calling a different >>> function with that name which can return two values and the "er" return >>> value can be nil. Which would result in the "er.Error()" call to >>> dereference a nil value. So I think you have incorrectly diagnosed the >>> cause of the problem. The first statement does not correctly handle "er" >>> being nil. The "fmt.Sprintf()" correctly handles "er" being the nil value. >>> >>> >>>> On Fri, Jun 6, 2025 at 6:29 PM Zhaoxun Yan <yan.zhao...@gmail.com> >>>> wrote: >>>> >>>>> -------------------- >>>>> panic: runtime error: invalid memory address or nil pointer dereference >>>>> [signal SIGSEGV: segmentation violation code=0x1 addr=0x18 pc=0x6646f2] >>>>> >>>>> goroutine 1 [running]: >>>>> util.CommandArgs({0xc000093cb0?, 0x2?, 0xc000071380?}) >>>>> /home/zxun/src/util/util.go:49 +0xf2 >>>>> -------------------- >>>>> This error occurred because package [main] uses a function called >>>>> "CommandArgs" from my self-built package [util] with args in another >>>>> package [conf] in the same directory. Package [util] got lost because it >>>>> does not know where is package [conf] >>>>> like this >>>>> [util] /home/zxun/src/util.go >>>>> [conf] /home/zxun/src/conf.go >>>>> [main] /home/zxun/src/main.go... >>>>> /home/zxun/src/go.mod: >>>>> >>>>> require( >>>>> util v0.0.0 >>>>> ... >>>>> replace util => ../util >>>>> >>>>> The usage line in main.go: >>>>> fmt.Println( util.CommandArgs([]string{conf.IreportExec, >>>>> conf.IreportScript, "redis"}) ) >>>>> >>>>> util.CommandArgs: >>>>> >>>>> func CommandArgs(args []string) string{ >>>>> if len(args) ==0{ >>>>> return "args are empty！" >>>>> } >>>>> var s string >>>>> if len(args) ==1{ >>>>> out, er := exec.Command(args[0]).CombinedOutput() >>>>> s = er.Error()+string(out) >>>>> }else{ >>>>> out, er := exec.Command(args[0],args[1:]...).CombinedOutput() >>>>> s = er.Error()+string(out) >>>>> fmt.Println(s) >>>>> } >>>>> return s >>>>> } >>>>> >>>>> So is my analysis correct? I have not seen s printed yet, because s >>>>> shall include "<nil>" at the beginning. I am using go1.18. If the cause is >>>>> util package cannot access a variable in conf, is it possible to walk >>>>> around by a deepcopy of the string array (which will be in package main)? >>>>> >>>>> Thanks in advance. >>>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "golang-nuts" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to golang-nuts+unsubscr...@googlegroups.com. >>>> To view this discussion visit >>>> https://groups.google.com/d/msgid/golang-nuts/CADEX6_Wzy%3DPoqdXBNUqQ0tGYmQfacTq6A%2By58a5osDkKB-Z1yA%40mail.gmail.com >>>> <https://groups.google.com/d/msgid/golang-nuts/CADEX6_Wzy%3DPoqdXBNUqQ0tGYmQfacTq6A%2By58a5osDkKB-Z1yA%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> >>> >>> -- >>> Kurtis Rader >>> Caretaker of the exceptional canines Junior and Hank >>> >> > > -- > Kurtis Rader > Caretaker of the exceptional canines Junior and Hank > > -- > You received this message because you are subscribed to the Google Groups > "golang-nuts" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to golang-nuts+unsubscr...@googlegroups.com. > To view this discussion visit > https://groups.google.com/d/msgid/golang-nuts/CABx2%3DD-_MxcMch21H-UhOX_N8Wf2A-8Gtb-WJ1DXqkh5YBAEGQ%40mail.gmail.com > <https://groups.google.com/d/msgid/golang-nuts/CABx2%3DD-_MxcMch21H-UhOX_N8Wf2A-8Gtb-WJ1DXqkh5YBAEGQ%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. 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