Zero Descriptor UID/GID (V2)

[tri-adam]

Mark UID/GID fields deprecated in type Descriptor struct, and set values to zero. Remove UID/GID values from info command output. Update integrity package tests to begin with zero value UID/GID. Don't consider deprecated UID/GID fields in GetFromDescr.

Closes #59

[codecov-commenter]

Codecov Report

Merging #61 (f7fe0ed) into master (08f0698) will increase coverage by 0.34%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #61      +/-   ##
==========================================
+ Coverage   69.82%   70.16%   +0.34%     
==========================================
  Files          25       25              
  Lines        1922     1904      -18     
==========================================
- Hits         1342     1336       -6     
+ Misses        390      384       -6     
+ Partials      190      184       -6     

Impacted Files	Coverage Δ
pkg/sif/fmt.go	71.08% <ø> (-0.69%)	⬇️
pkg/sif/lookup.go	69.36% <ø> (+1.22%)	⬆️
pkg/sif/sif.go	31.18% <ø> (ø)
pkg/sif/create.go	54.54% <100.00%> (+0.76%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 08f0698...f7fe0ed. Read the comment docs.

[dtrudg]

Since 0 infers root for uid/gid fields... would a -1 be acceptable here as a 'not used' value that distinguishes from 0 that might be present in older images.. given they are int and not uint definitions here?

[tri-adam]

Since 0 infers root for uid/gid fields... would a -1 be acceptable here as a 'not used' value that distinguishes from 0 that might be present in older images.. given they are int and not uint definitions here?

We could, although it's worth noting that the v1 API does use 0 to mean unset/ignore in at least one context (searching for descriptors):

sif/pkg/sif/lookup.go

Lines 227 to 232 in 08f0698

	if descr.UID != 0 && descr.UID != v.UID {
	continue
	}
	if descr.GID != 0 && descr.GID != v.GID {
	continue
	}

I have a slight preference for keeping it zero value, for no other reason than it being Go's default value, which reduces the number of references required to deprecated fields in tests that simulate the default behaviour (for example in the integrity tests that currently utilize the Descriptor type directly.)

Does that make sense?

[dtrudg]

Since 0 infers root for uid/gid fields... would a -1 be acceptable here as a 'not used' value that distinguishes from 0 that might be present in older images.. given they are int and not uint definitions here?

We could, although it's worth noting that the v1 API does use 0 to mean unset/ignore in at least one context (searching for descriptors):

sif/pkg/sif/lookup.go

Lines 227 to 232 in 08f0698

	if descr.UID != 0 && descr.UID != v.UID {
	continue
	}
	if descr.GID != 0 && descr.GID != v.GID {
	continue
	}

I have a slight preference for keeping it zero value, for no other reason than it being Go's default value, which reduces the number of references required to deprecated fields in tests that simulate the default behaviour (for example in the integrity tests that currently utilize the Descriptor type directly.)

Does that make sense?

Fair enough. It is one of those areas where it's pretty awkward that the default value is a meaningful one here, but this doesn't seem to have been used anywhere.