Review of #761 turned up three real defects and a feature that was visible
but not usable. All of it is fixed here, each defect with a regression test
that fails without the fix.
- A binding outlived the object it named. Deleting art left its entry in
`variables.bindings` forever: it counted as a skip in every dataset
application, `variable.list` counted it, and the saved file grew with every
delete. `Document::prune_variable_bindings` now lets them go after each
edit, as `prune_assets` does for Asset Export's.
- `Variables::prune` cleared `active_dataset` by comparing it against the
*variable* names being deleted. A dataset named like a variable lost its
active state when the variable went. The two are separate namespaces; the
block is gone (dataset.delete already did it right).
- `variable.delete` reported the number of names asked for, not the number
deleted, so deleting a name that was not there still said `deleted: 1`.
- `dataset.set` (new): a dataset's values could only be set when it was
created, so changing one meant deleting and rebuilding the row — losing its
place in the list and the active one. This replaces the row's values and
reports what it dropped.
- Window › Variables, and dialogs for the "…" commands. Every command had an
empty menu path and the command palette runs those with `{}`, so nothing
could be defined from the UI at all. The commands now carry their menu
path, the "…" ones open a Variables dialog (a name and a kind; a name and a
field per variable, its kind's editor), and `dataset.set` opens with the
row's own values.
- Locked art is neither bound nor rewritten by a dataset, and says so.
- `set_plain_text` told a node that existed but was not type that it was
missing.
- The panel had Document Info's icon, so the two were indistinguishable in
the collapsed column; it gets its own, plus New/Delete buttons, and its
rows say what their count is.
Format round trips now cover variables (the testkit fixture defines both
kinds, binds them and applies a row), and ROADMAP/README no longer list the
feature as missing.
cargo xtask ci: all 7 steps pass.