Fix#5242
Do this by first supplying the `servicePath` in `~/lib/plugins/lib/validate.js` and `~/lib/plugins/print.js` in a consistent manner with the code in `~/lib/classes/PluginManager.js`. Then, provide a default of `process.cwd()` for `servicePath` in `getCacheFilePath` and `getServerlessConfigFile`.
Fix `print`
The print command is highly linked to the `Variables` and `Service` codebases, keep those in sync and leave reminders about the link. Made these explicit and separately implemented to avoid complexity.
Additionally, the print command re-populates an object with the *very similar* content as the previously pre-populated service (just not augmented as just mentioned). This can lead to cross contamination between the two. As such, all caches must be cleared per unique invocation of service/object/property population.
Add tests for some expected but previously unverified behaviors.
Clean pre-population
The previous implementation worked okay but was unnecessary and would have been a maintenance problem. Instead, just knock out the population of variables depending on those config dependent services and use the standard means of resolution.
Fix cyclic bug (resulting from running print against a self-referencing serverless.yml)
The caching of values could lead to a cyclic object remaining in the caches for variable population. This causes crashes and pain. Solved by the cache cleaning logic.
Replace the existing service and clear the cache (which references the ammended service)
Remove cycles in that service using json-cycle.
Dump the decycled object as YAML to console.
