A folder id the account does not have rendered the ordinary empty state --
"Nothing here. This folder is empty." That is a claim about a folder that
is not there, so a stale link read as a folder that had emptied itself
rather than one that was gone (#111).
It now goes to the inbox and says why. Inbox is the kinder landing than a
dead end for a bookmark that has outlived its folder, but swapping one
folder for another without a word would be its own small lie, so it does
not do that either.
The condition worth writing a test around is not the unknown id, it is
the one guarding it. The folder list arrives after the first paint, so for
a moment *every* id is unknown, the right one included. Without that gate
this redirects on every cold load, from the folder the reader actually
asked for, and looks exactly like a flaky link -- a worse bug than the one
being fixed and a harder one to see. `isUnknownMailbox` is a small pure
function so that case can be pinned down rather than reasoned about.
Only ever reachable from outside the app, which is why it went unnoticed:
the sidebar links to ids that exist. A bookmark to a deleted folder, or a
folder link passed between accounts, is where it bites.
Verified against the mock: an unknown id lands on the inbox with the
message and a full list rather than an empty one, and a cold load straight
into a real folder stays in that folder with nothing said.
Closes#111.
jcoffey-dev
5a7cc5cc5a