Using pflag precludes the use of any other package written to use flag

[ziffusion]

This is because if you mix packages that use pflag with those that use flag, it requires you to call both flag.Parse() anf pflag.Parse() - one or both of which will fail.

This seems to be a crippling requirement because if I choose to use pflag, I am precluded from using any other third party package that uses flag.

[eparis]

You can use AddGoFlagSet to add all flag defined flags as pflag flags.

[ziffusion]

There is another use case that is still problematic.

There are cases where the program is passed flag style arguments automatically, which then fail when parsed by pflag.

A glaring example of this is in fact "go test" - which passes flags such as -test.v -test.trace etc. After importing flags from flag into pflag, "go test" fails.

[anthonyfok]

Reopening this to bring attention to fellow developers.

[epelc]

I also ran into this while using pflags with flags from go test ie -v.

Here is a workaround. It works by seperating the test flags and all other flags. Then it hands them off to the correct flag parser. Note you need go 1.6rc2(might work with rc1) as there is a bug in 1.5 which makes m.Run() call flags.parse even if they have already been parsed.
https://gist.github.com/epelc/02011f31bd7e227de1c8

[doublerebel]

I extended @epelc's gist to also filter goflags with values. It now works with -test.* flags or any other single-dash flags with or without values:

https://gist.github.com/doublerebel/8b95c5c118e958e495d2#file-your_test-go-L13

Wouldn't hurt to have this as a feature such as KeepGoFlagSet, so that existing software moving to pflag package can maintain backward compatibility.

[spf13]

I believe this commit cb88ea7 adds built in support for passing through test flags.

It's convenient that the go flag package uses a single dash followed by a string of characters containing a dot as that's invalid for posix shorthand flags and is easily identifiable and ignorable.

Closing this for now as it feels the core issue is resolved. If someone wants to create another issue requesting a new KeepGoFlagSet feature or similar please do.