Default keys for multi-text children (deephaven#293)

packages/components/src/spectrum/picker/PickerItemContent.tsx

@@ -27,17 +27,29 @@ export function PickerItemContent({
     // Boolean values need to be stringified to render
     content = String(content);
   } else if (Array.isArray(content)) {
-    // For cases where there are multiple `Text` children, add css class to
-    // handle overflow
-    content = content.map(item =>
+    // For cases where there are multiple `Text` children, add a css class to
+    // handle overflow. The primary use case for multiple text nodes is when a
+    // description is provided for an item. e.g.
+    // <Item textValue="Some Text">
+    //   <SomeIcon />
+    //   <Text>Some Label</Text>
+    //   <Text slot="description">Some Description</Text>
+    // </Item>
+    content = content.map((item, i) =>
       isElementOfType(item, Text)
-        ? // Cloning elements has the side effect of resetting React's internal
-          // `_store.validated` value to `false on each item. This causes them
-          // to be re-validated when they are rendered. Since they are inside of
-          // an array, React will show devtools warnings if they are missing `key`
-          // props.
-          cloneElement(item, {
+        ? cloneElement(item, {
             ...item.props,
+            // `cloneElement` has the side effect of resetting React's internal
+            // `_store.validated` value to `false on the item. This causes it
+            // to be re-validated as a child in an array when is is rendered,
+            // even if the item was originally provided as an inline child.
+            // Since React expects array children to have explicit keys, this
+            // will show devtools warnings for items that wouldn't usually
+            // require explicit keys. Since we are only cloning `Text` nodes, it
+            // should be reasonable to fallback to a key matching the stringified
+            // content. The index suffix is an extra precation for when 2 <Text>
+            // nodes have the same value.
+            key: item.key ?? `${item.props.children}_${i}`,
             UNSAFE_className: cl(
               item.props.UNSAFE_className,
               stylesCommon.spectrumEllipsis