From 24c59fbf40d5af58905890f5fbadc9de69ec2b44 Mon Sep 17 00:00:00 2001
From: Edward Langley <el-github@elangley.org>
Date: Thu, 9 Apr 2026 01:56:34 -0700
Subject: [PATCH] fix: Model::add_formula auto-adds target item; fix formula
 panel display
MIME-Version: 1.0
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Model::add_formula now ensures the formula target exists as an item in
the target category (same fix as AddFormula effect, but at the model
level — covers file loading and headless paths).

Formula panel now shows raw formula text instead of debug-formatted
string with redundant target name and quotes.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 src/model/types.rs      | 29 +++++++++++++++++++++++++++++
 src/ui/formula_panel.rs |  2 +-
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/src/model/types.rs b/src/model/types.rs
index 9a3600f..04b5699 100644
--- a/src/model/types.rs
+++ b/src/model/types.rs
@@ -172,6 +172,11 @@ impl Model {
     }
 
     pub fn add_formula(&mut self, formula: Formula) {
+        // Ensure the formula target exists as an item in the target category
+        // so the grid layout includes cells for it.
+        if let Some(cat) = self.categories.get_mut(&formula.target_category) {
+            cat.add_item(&formula.target);
+        }
         // Replace if same target within the same category
         if let Some(pos) = self.formulas.iter().position(|f| {
             f.target == formula.target && f.target_category == formula.target_category
@@ -731,6 +736,30 @@ mod model_tests {
         assert_eq!(result, Some(CellValue::Number(150.0)));
     }
 
+    /// Model::add_formula should add the formula target as an item to the
+    /// target category so the grid layout includes cells for it.
+    #[test]
+    fn add_formula_adds_target_item() {
+        use crate::formula::parse_formula;
+
+        let mut m = Model::new("Test");
+        m.add_category("Measure").unwrap();
+        m.add_category("Region").unwrap();
+        m.category_mut("Region").unwrap().add_item("East");
+        m.category_mut("Measure").unwrap().add_item("Revenue");
+        m.category_mut("Measure").unwrap().add_item("Cost");
+
+        m.add_formula(parse_formula("Profit = Revenue - Cost", "Measure").unwrap());
+
+        assert!(
+            m.category("Measure")
+                .unwrap()
+                .ordered_item_names()
+                .contains(&"Profit"),
+            "add_formula should add target item to category"
+        );
+    }
+
     #[test]
     fn evaluate_aggregated_no_hidden_delegates_to_evaluate() {
         let mut m = Model::new("Test");
diff --git a/src/ui/formula_panel.rs b/src/ui/formula_panel.rs
index e7cb5c1..16e35e8 100644
--- a/src/ui/formula_panel.rs
+++ b/src/ui/formula_panel.rs
@@ -50,7 +50,7 @@ impl PanelContent for FormulaContent<'_> {
         } else {
             Style::default().fg(Color::Green)
         };
-        let text = format!("  {} = {:?}", formula.target, formula.raw);
+        let text = format!("  {}", formula.raw);
         let truncated = if text.len() > inner.width as usize {
             format!("{}…", &text[..inner.width as usize - 1])
         } else {