I recently ran into a situation where building and debugging a SPFx web part seemed to go off the rails. Then I figured out that my normal pattern of skipping the ‘gulp clean’ command during project deployment had cause what I thought was bizarre behavior in Site Collection Features and toolbox.
I was working for a client that does not have a dedicated development or QA environment due primarily to political reasons. They also block access to all non-company tenants. Fortunately, I am able to do my development “off network” and once everything is ready, I move the code inside the firewall. Since this was an update to an existing web part, I knew deploying it to the same tenant as the existing web part was going to be tricky. The existing web part is on the company intranet home page, so getting into a site for testing without affecting the original web part meant deploying into a “QA” site app catalog. I thought this would work and there shouldn’t be any conflict. Famous last words …