Show auto primary keys in bulk insert preview

Render omitted auto integer primary key values as muted auto text in the bulk insert preview so generated IDs are easier to understand.

Expose the auto primary key flag in insert UI metadata and cover the preview behavior in Playwright.

datasette/static/app.css

@@ -1979,7 +1979,8 @@ textarea.row-edit-input {
     border-right: none;
 }
 
-.row-edit-bulk-preview-null {
+.row-edit-bulk-preview-null,
+.row-edit-bulk-preview-auto {
     color: var(--muted);
     font-style: italic;
 }

datasette/static/edit-tools.js

@@ -6038,6 +6038,25 @@ function bulkInsertPreviewValue(value) {
   return String(value);
 }
 
+function bulkInsertPreviewCell(column, hasValue, value) {
+  if (!hasValue && column.is_auto_pk) {
+    return {
+      text: "auto",
+      className: "row-edit-bulk-preview-auto",
+    };
+  }
+  if (value === null) {
+    return {
+      text: bulkInsertPreviewValue(value),
+      className: "row-edit-bulk-preview-null",
+    };
+  }
+  return {
+    text: hasValue ? bulkInsertPreviewValue(value) : "",
+    className: "",
+  };
+}
+
 function renderBulkInsertPreview(state, rows) {
   state.bulkInsertPreview.textContent = "";
   var summary = document.createElement("p");
@@ -6068,9 +6087,10 @@ function renderBulkInsertPreview(state, rows) {
       var td = document.createElement("td");
       var hasValue = Object.prototype.hasOwnProperty.call(row, column.name);
       var value = hasValue ? row[column.name] : "";
-      td.textContent = hasValue ? bulkInsertPreviewValue(value) : "";
-      if (value === null) {
-        td.className = "row-edit-bulk-preview-null";
+      var cell = bulkInsertPreviewCell(column, hasValue, value);
+      td.textContent = cell.text;
+      if (cell.className) {
+        td.className = cell.className;
       }
       tr.appendChild(td);
     });

datasette/views/table.py

@@ -205,7 +205,7 @@ class TableContext(Context):
     )
     table_insert_ui: dict = field(
         metadata={
-            "help": "Information needed to enable the row insertion UI, or ``None`` if row insertion is not available to the current actor. When present it has ``path``, ``tableName``, ``columns`` and ``primaryKeys`` keys; each column includes ``name``, ``sqlite_type``, ``notnull``, ``default``, ``has_default``, ``is_pk``, ``value_kind`` and ``column_type`` keys."
+            "help": "Information needed to enable the row insertion UI, or ``None`` if row insertion is not available to the current actor. When present it has ``path``, ``tableName``, ``columns`` and ``primaryKeys`` keys; each column includes ``name``, ``sqlite_type``, ``notnull``, ``default``, ``has_default``, ``is_pk``, ``is_auto_pk``, ``value_kind`` and ``column_type`` keys."
         }
     )
     table_alter_ui: dict = field(
@@ -507,6 +507,7 @@ async def _table_insert_ui(
             "default": column.default_value,
             "has_default": column.default_value is not None,
             "is_pk": is_pk,
+            "is_auto_pk": is_auto_pk,
             "value_kind": _column_value_kind_for_insert_form(column),
             "column_type": (
                 {"type": column_type.name, "config": column_type.config}

docs/template_context.rst

@@ -389,7 +389,7 @@ Many of these keys are shared with the :ref:`JSON API <json_api>` for this page.
     SQL definition for this table
 
 ``table_insert_ui`` - ``dict``
-    Information needed to enable the row insertion UI, or ``None`` if row insertion is not available to the current actor. When present it has ``path``, ``tableName``, ``columns`` and ``primaryKeys`` keys; each column includes ``name``, ``sqlite_type``, ``notnull``, ``default``, ``has_default``, ``is_pk``, ``value_kind`` and ``column_type`` keys.
+    Information needed to enable the row insertion UI, or ``None`` if row insertion is not available to the current actor. When present it has ``path``, ``tableName``, ``columns`` and ``primaryKeys`` keys; each column includes ``name``, ``sqlite_type``, ``notnull``, ``default``, ``has_default``, ``is_pk``, ``is_auto_pk``, ``value_kind`` and ``column_type`` keys.
 
 ``table_page_data`` - ``dict``
     JSON data used by JavaScript on the table page. Includes ``database``, ``table`` and ``tableUrl``, plus optional ``foreignKeys`` mapping column names to autocomplete URLs, optional ``insertRow`` data and optional ``alterTable`` data.

tests/test_playwright.py

@@ -1329,6 +1329,7 @@ def test_bulk_insert_omits_columns_absent_from_pasted_input(page, datasette_serv
     preview_text = dialog.locator(".row-edit-bulk-preview-table").inner_text()
     assert "Only title" in preview_text
     assert "undefined" not in preview_text
+    assert dialog.locator(".row-edit-bulk-preview-auto").inner_text() == "auto"
 
     dialog.locator(".row-edit-save").click()
     dialog.locator(