Enable filesync with debug

[briandealwis]

debug currently disables the Skaffold watcher to prevent Skaffold from redeploying artifacts on file changes: having a debug session ripped out when in progress is a suboptimal user experience! And many runtimes support installing changes, normally handled by the IDE.

But a side-effect is that this also disables the filesync functionality. We should be able to forego artifact redeployment while still supporting filesync.

[corneliusweig]

That sounds good, however it can also be confusing: Sync has to be configured by supplying sync patterns. If a file gets changed which does not match any of the sync patterns, the container is usually rebuilt. Now if some changes get applied (via sync in debug-mode) and others are not (because they would require a rebuild in debug-mode), this can be a bit confusing.
Overall, I'm not sure if we do our users a favor, if sync is enabled during debugging.

[briandealwis]

It seems some language runtimes, like Python, do not support a debugger-controlled hot-swap capability. VS Code and the Debug Adapter Protocol do not support installing code-changes either.

[corneliusweig]

@briandealwis Do I understand you correctly, that this also speaks against enabling sync in debug mode?

[briandealwis]

The opposite: Python's pydevd has some support for reloading changes from disk (pydev_reload). Haven't tried to figure out how to integrate it though.

[tstromberg]

Is this still an issue?

[briandealwis]

Yes.