Make mode optional?

[AkihiroSuda]

https://github.com/stevvooe/continuity/blob/master/proto/manifest.proto

Since mode is currently defined as uint32, there is no way to omit mode from the manifest
(zero should be interpreted as zero, not nil)

Or maybe it should bbetter to clarify that mode is mandatory field and cannot be omitted, but I'm not sure it causes compatibility issue

[stevvooe]

Fields in proto3 cannot be optional. Mode is required.

Is there a use case for not specifying the file mode?

[AkihiroSuda]

My intent was for the root dir issue discussed in https://github.com/docker/containerd/issues/523, but on second thought I found that the ModeDir bit is still required.
So I'm closing this issue.

However, for context.Verify(), I think we still need some umask-like feature for the issue mentioned above and for non-UNIX filesystems such as FAT.

[stevvooe]

However, for context.Verify(), I think we still need some umask-like feature for the issue mentioned above and for non-UNIX filesystems such as FAT.

Could you clarify that request in another issue?

[AkihiroSuda]

sure, opened #49