Segmentation masks 1.1 dumping annotations

[aschernov]

My actions before raising this issue

• Read/searched the docs
• Searched past issues

Expected Behaviour

All frames should dump with a segmentation mask

Current Behaviour

Noticed that when we dump annotation in the segmentation masks 1.1 format some frames don't contain a mask even if they were correctly annotated.
In the annotation tool this frame look so. As we can see it's fully annotated:

And so it dumps in the segmentation mask 1.1 format:

Possible Solution

Steps to Reproduce (for bugs)

1.Annotate images with polygons using z-order
1.Dump the annotation in segmentation mask 1.1 format
1.Check the images inside the zip archive you'll get

Context

Your Environment

• Git hash commit (git log -1):
• Docker version docker version (e.g. Docker 17.0.05):
• Are you using Docker Swarm or Kubernetes?
• Operating System and version (e.g. Linux, Windows, MacOS):
• Code example or link to GitHub repo or gist to reproduce problem:
• Other diagnostic information / logs:
  Logs from `cvat` container

Next steps

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[zhiltsov-max]

Is it possible that this image had the red rectangle annotation (background) with lesser z_order than others? This is the only possible reason I can come up with now.

[nmanovic]

@aschernov , could you please attach an annotation file which the issue?

[zhiltsov-max]

I've checked already. Seems really strange, especially taking into account that the same actions in Datumaro done manually give the expected result.

[aschernov]

2020_05_21_16_08_19-cvat for images 1.1.zip
2020_05_21_16_08_19-segmentation mask 1.1.zip