cmd/go: -keepfuzzing needs renaming, does not exist

[rsc]

Generally, we try to keep the flag names big-endian, so that related flags all have a common prefix, like bench, benchtime, benchmem; memprofile, memprofilerate; even fuzz, fuzzcachedir, fuzzminimizetime, fuzztime, fuzzworker.

The exception in the go help testflag output is keepfuzzing, which doesn't begin with fuzz. It probably should. Maybe fuzzmore?

Also the flag seems not to be implemented.

% gotip test -v -fuzz=Fuzz -keepfuzzing
flag provided but not defined: -keepfuzzing
Usage of /tmp/go-build1779596492/b001/pkg.test:
	...

/cc @jayconrod @katiehockman

[ameowlia]

fuzzforever? fuzzon? fuzznonstop?

[rsc]

fuzzcontinue would probably be fine.

[katiehockman]

https://go-review.googlesource.com/c/go/+/351113 removed the documentation for -keepfuzzing since it likely won't make it into this release. (And can always be added back if it does for whatever reason)
So I'll remove the release-blocker label.

-fuzzcontinue seems reasonable to me for when we implement it.

[rogpeppe]

FWIW I'd expect this to be the default - if I'm leaving something fuzzing for days or weeks (as I'm doing currently), I don't want it to stop immediately it finds a crash.
I was surprised when I found out that it did.

Possible flag name: -fuzzonce with the opposite sense to -fuzzcontinue? -fuzzstoponfail ?

[cespare]

@rogpeppe or use the existing -failfast flag?

(Though I'm not sure I agree about inverting the default behavior.)

[AlekSi]

or use the existing -failfast flag?

See #45690

[katiehockman]

This won't happen for 1.18, but I'd like to see it in 1.19. Updated the milestone.

[ianlancetaylor]

CC @golang/fuzzing

Do we want this? The milestone is currently 1.19. Should it be 1.20? Backlog? Thanks.