fix(datagrid): distinguish missing and empty descriptions

CHANGELOG.md

@@ -14,6 +14,7 @@
  - `stacked` is now ignored on chart types that cannot stack, instead of displaying an empty chart.
  - Screen readers now announce the title of the modal component instead of an unnamed dialog.
  - `sqlpage.request_body` and `sqlpage.request_body_base64` now return NULL when the request has no body. A body that cannot be read, such as one exceeding the payload limit, is now reported as an error instead of being silently replaced with an empty body.
+ - Datagrid rows with an icon or image no longer display an unnecessary en-dash placeholder, and an explicitly empty description remains empty.
  - Charts can display reference lines. A row with a `yline` is drawn as a line across the chart at that value of the y axis, with the row's `label` and `color` for its text and its color. Reference lines are rows, so a chart can have as many of them as the query returns. A line follows its axis, so on a `horizontal` bar chart a `yline` is drawn down the chart rather than across it. They are not added to the total of a `stacked` chart, and are not filled in an `area` chart.
 
 ## v0.45

sqlpage/templates/datagrid.handlebars

@@ -42,6 +42,9 @@
                         {{/if}}
                         {{#if description}}
                             {{description}}
+                        {{else if (eq description "")}}
+                        {{else if icon}}
+                        {{else if image_url}}
                         {{else}}
                             –
                         {{/if}}

tests/components/datagrid_icon_only.sql

@@ -0,0 +1,4 @@
+SELECT 'datagrid' AS component;
+SELECT 'Facebook' AS title, 'brand-facebook' AS icon;
+SELECT 'Empty' AS title, '' AS description;
+SELECT 'Missing' AS title;

tests/core/mod.rs

@@ -40,6 +40,20 @@ async fn test_concurrent_requests() {
     }
 }
 
+#[actix_web::test]
+async fn test_datagrid_description_presence_controls_placeholder() {
+    let resp = req_path("/tests/components/datagrid_icon_only.sql")
+        .await
+        .unwrap();
+    assert_eq!(resp.status(), StatusCode::OK);
+    let body = String::from_utf8(test::read_body(resp).await.to_vec()).unwrap();
+    assert!(body.contains("Facebook"), "{body}");
+    assert!(body.contains("Empty"), "{body}");
+    assert!(body.contains("Missing"), "{body}");
+    assert!(body.contains("<svg"), "{body}");
+    assert_eq!(body.matches('–').count(), 1, "{body}");
+}
+
 #[actix_web::test]
 async fn test_routing_with_db_fs() {
     let mut config = test_config();