"--locked" flag ignored in "cross build"

[RalfJung]

In japaric/xargo#264 I am trying to ensure that xargo's lockfile is up-to-date on CI, so I added --locked to our cross build invocation. However, that seems to have no effect: even with a stale lockfile, and even with no lockfile at all, the build succeeds!

Silently ignoring important CLI flags like that seems quite surprising, so I was wondering if this is deliberate and if there's any way to do a locked build here.

[reitermarkus]

Not sure why it would do that. All flags are passed through to cargo in the container. You can check that with the --verbose flag.

[RalfJung]

Maybe something runs cargo update or some similar command first that would result in the lockfile not being any more the original one?

[reitermarkus]

Ok, so it seems obvious that this must be the culprit:

https://github.com/rust-embedded/cross/blob/ea29a50d236bd5bda5b9eb14ab04dedb46c96d96/src/docker.rs#L101-L108

[RalfJung]

Yes. That one should likely also have --locked when that flag is set for the main command.