External Inconsistency Flag

[okennedy]

For reasons of performance/sanity, we've been forced to make a number of compromises on reproducibility. For example, LOAD DATASET can read from a URL or from the local filesystem (and that's generally desirable!). However, if the underlying file changes... the resulting dataset/workflow becomes stale.

We should be able to communicate this situation to users. The proposed approach is to define a new cell state (name TBD, tentative: INCONSISTENT) that indicates that the cell is valid w.r.t. the current workflow, but stale w.r.t., the outside world. Planned implementations include:

• [ ] LOAD DATASET cells reading from the local FS can use timestamps and hashes to flag when the underlying file has changed
• [ ] PYTHON cells should flag when the python environment being used has changed destructively (new package version, deleted package)