[bst-1] bst build --track-all doesn't build anything

Summary

Sometimes, running bst build with --track-all behaves as if I ran bst track. It tracks all element but doesn't try to build or pull anything.

Note

This issue is mostly fixed, but it seems to reproduce spuriously now, keeping this open to record any information pertaining to any further sightings of this issue.

Steps to reproduce

Using branch abderrahim/gnome-boot of gnome-build-meta, run

bst --no-strict --on-error continue build --track-all vm/desktop-vm-image-x86_64.bst

What is the current bug behavior?

Pipeline Summary
  Total:       613
  Session:     555
  Track Queue: processed 232, skipped 13, failed 0
  Pull Queue:  processed 0,   skipped 0,  failed 0
  Fetch Queue: processed 0,   skipped 0,  failed 0
  Build Queue: processed 0,   skipped 0,  failed 0
  Push Queue:  processed 0,   skipped 0,  failed 0

What is the expected correct behavior?

bst should try to pull/build things.

Other relevant information

This is using bst 1.2.6, in non strict mode.

• BuildStream version affected: /milestone %BuildStream_v1.2

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