Unexpected caching behaviour with bst plugin

Summary

I have been developing a plugin for bst, which gathers json manifests as part of a pipeline. I have a version of this, which is already cached in our shared bst cache server on freedesktop-sdk. However when modifying this plugin locally, bst has been pulling the cached version, which has lead to a lot of confusion, when trying to debug a change I made locally, as the updated local version was not being applied, instead the cached plugin was used.

Steps to reproduce

The branch here could be modified locally and rebuilt, which would then show how the local changes are not applied, bst instead seems to pull the old version from the cache.

What is the current bug behavior?

When rebuilding a plugin locally bst does not seem to calculate the plugin has changed locally and pulls an old version from the cache.

I have tried removing my local cache, but bst will just fetch from the remote. I have also tried increasing the version number found in the project.conf definition, which did not stop bst from pulling the older version from the cache.

What is the expected correct behavior?

The local changes should rebuilt/applied, which will prevent any confusion for the user when they receive the wrong output, from an older version.

The fact the plugin source changed and i was still receiving invalid values caused me a lot of confusion, i use the self.status() method in bst to log debug info, which appeared to suppressed by bst, however it wasn't, it was actually just not being called at all.

Relevant logs and/or screenshots

In this this build, however the plugin logic has changed to fix this indexing issue, and was rebased on top of the old logic. You can see from the logs that the plugin was cached and the build then failed with the original python error that was actually fixed locally.

In this build you can see how i changed the required version of the plugin, but bst still decided to pull the cached version.

Other relevant information

BuildStream version affected: /milestone %BuildStream_v1.2.3