fix(display): defer the formula-result display: the surrogate cannot find the target's category (improvise-cq1q.13)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VdfEGXA7aJ6ftMsCc9PJze

context/code/core.md

@@ -1798,8 +1798,8 @@ Still keys: `GridLayout::row_label`/`col_label` (commands match on them),
 message that names a thing which exists. The title is the active view's display:
 the TUI reads `app.view().display()`, the browser `ViewListCache::display_of`
 (key when the list lacks the view). The statuses are the axis change (panel and
-tile bar), `Filter:`, `Deleted category/item`, the formula-result and non-item
-refusals, and the item-add prompt. Both ends say them through the same
+tile bar), `Filter:`, `Deleted category/item`, the non-item
+refusal, and the item-add prompt. Both ends say them through the same
 `viewmodel` builders, so a wording is not spelled twice. The host reads
 `Model::category_display`/`item_display`; the client reads
 `CategoryTreeCache::category_display`/`item_display`. Each falls back to the key.
@@ -1812,9 +1812,11 @@ names what was just typed, whose display equals its key at creation. A stray
 coordinate in `non_item_refusal` is a key for the same reason; only the category
 beside it is a display. **A display must never reach a lookup**: the item-add
 mode keeps the category key (`AppMode::item_add_shown(key, shown)`) and the prompt
-alone carries the display. A formula target has no display path yet
-(`set_item_display` needs an explicit `_Measure` item), so `derived_refusal` reads
-`item_display("_Measure", target)` and in practice says the key.
+alone carries the display. A formula-result refusal still says the target's key
+(improvise-cq1q.13 deferred it). A target in `_Measure` is implied by its formula
+and is no item, so it has no display to read. One in a regular category is a real
+item, but `CellId::Derived` carries only the target, so neither end can find its
+category. Both need that surrogate to carry the category first.
 
 `AxisFrame::cat_displays` is projected and validated, but nothing paints it yet
 (the corner label has no consumer); that is a gap to close when one does, not a

context/test-evidence/core.md

@@ -2175,11 +2175,10 @@ Rival: the mode is built with the display as its category
 (`item_add_shown(shown, ..)`); the prompt reads right and the commit would add to
 a category that does not exist. The test fails on `category == "Region"`.
 
-### resolve::display_tests::a_refused_cell_names_the_displays_it_shows
+### resolve::display_tests::a_refused_cell_names_the_category_it_shows
 
-Rival: the non-item refusal gets the category key. The derived arm is covered by
-the item display for `_Measure`; the stray coordinate stays a key because it names
-no item and has no display.
+Rival: the non-item refusal gets the category key. The stray coordinate stays a key
+because it names no item and has no display.
 
 ### command::cmd::panel::tests::a_panel_status_names_what_a_person_sees_not_the_keys
 
@@ -2193,12 +2192,6 @@ axis status passes `cat_name` (fails); the filter status passes the item key
 Rival: the status formats `name`. It fails on both the present display and the
 absent key.
 
-### command::cmd::cell::tests::a_refusal_names_the_formulas_display_not_its_key
-
-A formula target has no display path today: `set_item_display` needs an explicit
-`_Measure` item, so the fixture adds one named like the target. Rival:
-`derived_refusal` skips the lookup; the test fails on "Operating profit...".
-
 ### ui::app::non_item_key_tests::a_non_item_refusal_names_the_categorys_display
 
 Rival, run once per site: the refusal in `EditOrDrill` (the `i` key) and the one in
@@ -2210,8 +2203,8 @@ The third site, `uneditable` in `cmd/core.rs`, which only a commit reaches once
 editor is open (`:enter-mode editing`). Rival: it passes the key; the two tests
 above stay green and this one fails.
 
-### ui::app::non_item_key_tests::a_refused_wire_write_names_the_displays_it_shows
+### ui::app::non_item_key_tests::a_refused_wire_write_names_the_category_it_shows
 
-The wire's own refusals in `Grids::unwritable`: the non-item arm and the formula
-arm (once a third copy of the derived wording, now `derived_refusal`). Rivals: the
-category key; a model with no display for the formula. Each fails.
+The wire's own refusal in `Grids::unwritable`. Rival: the category key; fails. The
+formula arm (once a third copy of the derived wording, now `derived_refusal`) is
+pinned to its wording so the consolidation cannot change what it says.

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

@@ -494,24 +494,6 @@ mod tests {
         app
     }
 
-    #[test]
-    fn a_refusal_names_the_formulas_display_not_its_key() {
-        let mut app = formula_app();
-        let measure = app.model_state.workbook.model.category_mut("_Measure");
-        let measure = measure.unwrap();
-        measure.add_item("Profit");
-        measure.set_item_display("Profit", "Operating profit after all costs");
-        app.cursor_mut().selected = (1, 2);
-        press(&mut app, 'p');
-        assert!(
-            app.view_state
-                .status_msg
-                .contains("Operating profit after all costs is computed"),
-            "got {:?}",
-            app.view_state.status_msg
-        );
-    }
-
     /// improvise-54g1 — see context/test-evidence/command.md.
     #[test]
     fn p_onto_a_formula_owned_cell_writes_nothing_and_names_the_formula() {

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

@@ -23,8 +23,7 @@ pub const INSIDE_A_DRILL_REFUSAL: &str =
     "A value is not staged inside a drill — edit the cell instead";
 
 /// What a command says when the cell it would write is a formula's result.
-pub fn derived_refusal(model: &Model, target: &str) -> String {
-    let target = model.item_display("_Measure", target);
+pub fn derived_refusal(target: &str) -> String {
     format!("{target} is computed by a formula — edit the formula, not the cell")
 }
 
@@ -39,7 +38,7 @@ pub fn uneditable(model: &Model, layout: &GridLayout, row: usize, col: usize) ->
             }
             .to_string(),
         ),
-        Some(CellId::Derived { target }) => Some(derived_refusal(model, &target)),
+        Some(CellId::Derived { target }) => Some(derived_refusal(&target)),
         Some(CellId::NonItem { category, item }) => {
             Some(non_item_refusal(model.category_display(&category), &item))
         }
@@ -132,7 +131,7 @@ impl<'a> CmdContext<'a> {
         match self.cursor_cell_id() {
             Some(CellId::Record(_)) => self.stored_cell_key(),
             Some(CellId::Aggregate(_)) => Err(self.aggregate_refusal()),
-            Some(CellId::Derived { target }) => Err(derived_refusal(self.model, &target)),
+            Some(CellId::Derived { target }) => Err(derived_refusal(&target)),
             Some(CellId::Create(_) | CellId::Coordinate { .. }) => {
                 Err(NO_VALUE_REFUSAL.to_string())
             }

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

@@ -386,7 +386,6 @@ impl Cmd for EditOrDrill {
         // the synthetic key names no measure, so the record's key is resolved.
         if let Some(formula) = ctx.owning_formula() {
             return vec![effect::refuse(super::core::derived_refusal(
-                ctx.model,
                 &formula.target,
             ))];
         }

crates/improvise-command/src/ui/app.rs

@@ -334,7 +334,7 @@ impl Grids<'_> {
         let model = &self.app.model_state.workbook.model;
         let derived = model
             .formula_for(&key)
-            .map(|f| crate::command::cmd::core::derived_refusal(model, &f.target));
+            .map(|f| crate::command::cmd::core::derived_refusal(&f.target));
         let refusal = self.app.non_item_refusal(&key).or(derived);
         refusal.or_else(|| self.aggregate_refusal(view, cell.record, &key))
     }
@@ -5618,9 +5618,8 @@ mod non_item_key_tests {
     }
 
     #[test]
-    fn a_refused_wire_write_names_the_displays_it_shows() {
+    fn a_refused_wire_write_names_the_category_it_shows() {
         const REGION: &str = "Sales territory of the whole company";
-        const PROFIT: &str = "Operating profit after all costs";
         let mut app = paged_app("East");
         let stray = CellKey::new(vec![
             ("Month".into(), "Jan".into()),
@@ -5633,9 +5632,6 @@ mod non_item_key_tests {
         model.add_formula(
             crate::formula::parse_formula("Profit = Revenue - 1", "_Measure").unwrap(),
         );
-        let measure = model.category_mut("_Measure").unwrap();
-        measure.add_item("Profit");
-        measure.set_item_display("Profit", PROFIT);
         let refused = |key: &CellKey, measure: &str| {
             let cell = RecordCell {
                 record: RecordHash::of(key),
@@ -5655,7 +5651,7 @@ mod non_item_key_tests {
             ("_Measure".into(), "Profit".into()),
         ]);
         let why = refused(&profit, "Profit").expect("a formula's result is refused");
-        assert!(why.starts_with(PROFIT), "{why}");
+        assert!(why.starts_with("Profit is computed by a formula"), "{why}");
     }
 
     #[test]

crates/improvise-protocol/src/resolve.rs

@@ -963,9 +963,7 @@ fn edit_or_drill(state: &ClientState, mode: AppMode) -> Option<Vec<Command>> {
             "an aggregate is edited by drilling in — {}",
             not_yet("drill")
         ))]),
-        CellId::Derived { target } => {
-            Some(vec![Command::SetStatus(derived_decline(state, target))])
-        }
+        CellId::Derived { target } => Some(vec![Command::SetStatus(derived_decline(target))]),
         // Both creating columns are records-only, so the guard above takes
         // them; declining rather than `None` keeps that a door, not a hole.
         CellId::Create(_) => Some(vec![Command::SetStatus(not_yet("creating a column"))]),
@@ -1408,7 +1406,7 @@ fn reopened_at(
 pub(crate) fn declined_at(state: &ClientState, row: usize, col: usize) -> Option<String> {
     match projected_at(state, row, col)?.id.as_ref()? {
         CellId::Aggregate(_) => Some(AGGREGATE_DECLINE.to_string()),
-        CellId::Derived { target } => Some(derived_decline(state, target)),
+        CellId::Derived { target } => Some(derived_decline(target)),
         CellId::NonItem { category, item } => Some(crate::non_item_refusal(
             state.categories.category_display(category),
             item,
@@ -1445,8 +1443,7 @@ const AGGREGATE_DECLINE: &str =
     "Cannot write to an aggregate — it combines several records, so there is no one cell to write";
 
 /// What both ends say of a formula's result: the host's `derived_refusal`.
-fn derived_decline(state: &ClientState, target: &str) -> String {
-    let target = state.categories.item_display("_Measure", target);
+fn derived_decline(target: &str) -> String {
     format!("{target} is computed by a formula — edit the formula, not the cell")
 }
 
@@ -5044,7 +5041,6 @@ mod display_tests {
 
     const REGION: &str = "Sales territory of the whole company";
     const NORTH: &str = "Northern reaches and the colder coasts";
-    const TOTAL: &str = "Grand total of everything counted";
 
     fn ev(code: KeyCode) -> KeyEvent {
         KeyEvent::new(code, KeyModifiers::NONE)
@@ -5065,20 +5061,12 @@ mod display_tests {
         state.bootstrap(Snapshot {
             view: ViewState::default(),
             seed: vec![
-                Projection::CategoryTree(CategoryTreeUpdate::Categories(vec![
-                    CategoryRow {
-                        name: "Region".into(),
-                        display: REGION.into(),
-                        items: vec![shown("North", NORTH)],
-                        axis: Axis::Row,
-                    },
-                    CategoryRow {
-                        name: "_Measure".into(),
-                        display: "_Measure".into(),
-                        items: vec![shown("Total", TOTAL)],
-                        axis: Axis::Column,
-                    },
-                ])),
+                Projection::CategoryTree(CategoryTreeUpdate::Categories(vec![CategoryRow {
+                    name: "Region".into(),
+                    display: REGION.into(),
+                    items: vec![shown("North", NORTH)],
+                    axis: Axis::Row,
+                }])),
                 Projection::TileBar(vec![TileEntry {
                     category: "Region".into(),
                     display: REGION.into(),
@@ -5172,12 +5160,7 @@ mod display_tests {
     }
 
     #[test]
-    fn a_refused_cell_names_the_displays_it_shows() {
-        let derived = displayed(Some(CellId::Derived {
-            target: "Total".into(),
-        }));
-        let said = last_status(local(&derived, KeyCode::Char('i')));
-        assert!(said.starts_with(TOTAL), "{said}");
+    fn a_refused_cell_names_the_category_it_shows() {
         let stray = displayed(Some(CellId::NonItem {
             category: "Region".into(),
             item: "Mars".into(),