ko resolve segfaults when push=false

[ian-mi]

When push=false there are no publishers and multiPublisher.Publish will return a nil name.Reference causing a segfault:

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x38 pc=0x1610af5]

goroutine 13 [running]:
github.com/google/ko/pkg/resolve.ImageReferences.func1(0x1, 0x665a99)
/usr/local/google/home/ianmi/go/pkg/mod/github.com/google/[email protected]/pkg/resolve/resolve.go:66 +0x115
golang.org/x/sync/errgroup.(*Group).Go.func1(0xc000362a80, 0xc0000b6230)
/usr/local/google/home/ianmi/go/pkg/mod/golang.org/x/[email protected]/errgroup/errgroup.go:57 +0x59
created by golang.org/x/sync/errgroup.(*Group).Go
/usr/local/google/home/ianmi/go/pkg/mod/golang.org/x/[email protected]/errgroup/errgroup.go:54 +0x66

[imjasonh]

What command were you running?

I tried with ko publish <importpath> --push=false and it succeeded (though it logged the final line <nil>...)

ko apply did fail with the stacktrace though.

[jonjohnsonjr]

#166

[imjasonh]

WIP at master...ImJasonH:multi-panic

It gets around this by injecting not-published@sha256...

Edit: we shouldn't go with that placeholder, but that's the idea

[jonjohnsonjr]

As mentioned in the other bug, there doesn't seem to be any utility in just setting push=false without any other publisher. We should just return a descriptive error here.

@ian-mi does that sound right or are you interested in some kind of NOP publisher as a dry run?

[ian-mi]

I think it'd be great to have a dry run mode for testing purposes as that's how I was attempting to use the push flag. I can open a separate feature request for that, however.

…

On Mon, Oct 5, 2020, 3:11 PM jonjohnsonjr ***@***.***> wrote: As mentioned in the other bug, there doesn't seem to be any utility in just setting push=false without any other publisher. We should just return a descriptive error here. @ian-mi <https://github.com/ian-mi> does that sound right or are you interested in some kind of NOP publisher as a dry run? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#215 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABO2RCRB2QMWAXD2MWHMYBTSJJACPANCNFSM4SFGHOTA> .

[imjasonh]

Updated the PR to do a nop push. This ignores -P or -B flags, and always uses -P behavior.