Express dependency of one resource on the latest version of another resource

I would like a way to say "'foo' depends on 'bar'. If 'bar' changes, reload 'foo' with the most recent and up-to-date version of bar".

For example, in my team's Tiltfile, we have a local_resource which runs unit tests for our main webapp. I've set a dependency in the testing local resource on the webapp, i.e. local_resource('run_tests', cmd='./run_tests.sh', ..., resource_deps=['core-webapp']). In practice, I've found that updating core-webapp triggers a test run, but usually the test run is against an out of date version of the webapp. This makes it appear that a test is still broken, even if the most recent change fixes it, and makes it look like tests are fine, even when the most recent change broke things. Usually, manually running tests a second time shows correct results.

https://docs.tilt.dev/resource_dependencies.html says "This feature currently mostly only helps in the common case that different versions of services are broadly compatible with each other, and focuses on ensuring that some instance of a resource’s dependencies exist, without worrying too much about whether it’s a current version. For this reason, resource_deps currently only affects the first build after a tilt up. e.g., Once any version of database has been running at least once, its dependencies are unblocked to build for the rest of Tilt’s lifetime."

We would like to depend on the current version, please!

Start with resource_dependencies.html and the local_resource/resource_deps behavior described in the issue. Reproduce the example from the Tiltfile to observe when a dependent resource runs relative to its dependency. Done means dependencies use the most recent version, rather than merely any previously started version, and the documented behavior is updated.