Merge pull request #192 from fiddlerwoaroof/fix/jgzw-tile-virtuals

jgzw: keep _Index/_Dim tileable, and pin the offered set by name

context/code/command.md

@@ -2874,6 +2874,43 @@ flag: tidy-up goes where an abort cannot reach it.
 stays in `TileSelect` mode so the user can adjust several tiles. `axis: None` cycles;
 `axis: Some(a)` sets.
 
+**The tile bar offers `_Index` and `_Dim`, and that is deliberate (improvise-jgzw).**
+Every tile call site passes `Model::category_names()`, virtual categories included,
+so tile cursor 0 is `_Index`. The ticket asked whether that was a leak. It is not,
+for three reasons, each checked rather than argued:
+
+- **It is a decision the user already made.** improvise-kos: "`_Dim` and `_Index`
+  should work as pivot axes outside Records/Drill view". A category that works as a
+  pivot axis is one the axis picker offers.
+- **The tile bar is the only way out of a records layout that was saved.**
+  improvise-jgzw's "check what it does" found that hand-assigning `_Index` → Row and
+  `_Dim` → Column in a real view (tile bar or `:set-axis`) is **written** to the
+  `.improv`, because a real view persists every axis, and it reopens as records mode.
+  (`VIRTUAL_VIEW_NAMES`' "never-persisted `_Index`/`_Dim` on axes" is true only of
+  `_Records`/`_Drill`.) In that document, `R` (`toggle-records-mode`) emits
+  `ViewBack` on an empty back stack, so it leaves the layout as it was and sets the
+  status to "Pivot mode". That is filed as improvise-gj5p. Moving the two axes back through
+  the tile bar is what gets out. In the browser, which declines
+  `toggle-records-mode`, the tile bar is also the only way in, and improvise-bd9o
+  already made that route safe instead of closing it
+  (`the_tile_bar_route_into_records_mode_does_not_strand_the_user`).
+- **What filtering would cost was measured.** With `View::tileable_cats` filtering
+  on `CategoryKind::is_index_or_dim`, that bd9o test and the TUI's
+  `renders_each_tile_with_its_axis_label` fail, as well as the two characterization
+  tests here.
+
+What the default cursor does cost, stated: one cycle key on tile 0 puts `_Index`
+on Row alone, and in a pivot view that empties the grid (0 rows on
+`web/demo.improv`). The status line says `_Index → Row`, and three more presses
+undo it. If that turns out to matter, the fix is the order the tile bar lists
+categories in, not taking entries out of it.
+
+**`_Measure` must stay tileable.** It is on an axis in every shipped document, so
+`regular_category_names()`, the advice for *prompts*, is the wrong filter here.
+`the_tile_bar_offers_every_category_by_name_measure_and_records_axes_included`
+names the whole offered list with `_Measure` on a column, and fails if either
+decision changes.
+
 ### `cmd/effect_cmds.rs`
 
 The parseable model-mutation commands are thin `Cmd` wrappers around effects,

context/test-evidence/command.md

@@ -5313,3 +5313,27 @@ refusal is recorded and the mode is not `Quit`. `import-json` failed first,
 before `refuse_and_stop` was applied to its arms. For `load`, the injected fault
 is removing its abort (`refuse_and_stop` back to `app.refuse`), and the test
 then fails with "`load absent.improv . q` quit having loaded nothing".
+
+## `command/cmd/tile.rs` — the tile bar's offered set, by name (improvise-jgzw)
+
+### the_tile_bar_offers_every_category_by_name_measure_and_records_axes_included
+
+This test pins a decision, not a bug. The argument is in `context/code/command.md`
+under `cmd/tile.rs`. Before this test, no tile assertion named the whole offered
+set. The two older ones named only the category at cursor 0, so a filter that
+changed what the bar offers past the cursor was invisible. The fixture puts
+`_Measure` on **Column**, as every shipped document does. The test then walks the
+cursor past the end and asserts the exact list
+`[_Index, _Dim, _Measure, Type, Month]`.
+
+Rivals, injected, full workspace run:
+
+- **`regular_category_names()` in `TileAxisOp`**, the obvious "no virtual
+  categories in pickers" fix, which drops `_Measure` too. It fails this test
+  (`["Type", "Month"]`), the two characterization tests above it, and
+  `lockstep.rs::a_locally_resolved_tile_axis_change_agrees_with_the_host`.
+- **`View::tileable_cats` filtering `is_index_or_dim`**, the ticket's option (b).
+  With the list asserted this test fails by construction, so the point is what
+  *else* fails: `renders_each_tile_with_its_axis_label` (TUI) and
+  `the_tile_bar_route_into_records_mode_does_not_strand_the_user`. The second one
+  is improvise-bd9o's own test of the route this decision keeps.

crates/improvise-command/src/command/cmd/tile.rs

@@ -59,6 +59,26 @@ mod tests {
         assert!(effects.is_empty());
     }
 
+    /// improvise-jgzw: `_Index`/`_Dim` stay tileable on purpose, and `_Measure` on
+    /// a column must too — `context/test-evidence/command.md`.
+    #[test]
+    fn the_tile_bar_offers_every_category_by_name_measure_and_records_axes_included() {
+        let mut m = two_cat_model();
+        m.active_view_mut().set_axis("_Measure", Axis::Column);
+        let layout = make_layout(&m);
+        let reg = make_registry();
+        let mut ctx = make_ctx(&m, &layout, &reg);
+        let mut offered = Vec::new();
+        for idx in 0..8 {
+            ctx.tile_cat_idx = idx;
+            let dbg = effects_debug(&TileAxisOp { axis: None }.execute(&ctx));
+            if let Some(rest) = dbg.split("CycleAxis(Active, \"").nth(1) {
+                offered.push(rest.split('"').next().unwrap_or_default().to_string());
+            }
+        }
+        assert_eq!(offered, ["_Index", "_Dim", "_Measure", "Type", "Month"]);
+    }
+
     #[test]
     fn move_tile_cursor_right() {
         let m = two_cat_model();