Don't explain an explain even in the demo, refs #2293

docs/plugin_hooks.rst

@@ -1557,7 +1557,10 @@ This example adds a new query action linking to a page for explaining a query:
 
 
     @hookimpl
-    def query_actions(datasette, database, sql):
+    def query_actions(datasette, database, query_name, sql):
+        # Don't explain an explain
+        if sql.lower().startswith("explain"):
+            return
         return [
             {
                 "href": datasette.urls.database(database)
@@ -1571,7 +1574,6 @@ This example adds a new query action linking to a page for explaining a query:
             },
         ]
 
-
 .. _plugin_hook_database_actions:
 
 database_actions(datasette, actor, database, request)

tests/plugins/my_plugin.py

@@ -393,11 +393,9 @@ def table_actions(datasette, database, table, actor):
 
 @hookimpl
 def query_actions(datasette, database, query_name, sql):
-    args = {
+    # Don't explain an explain
-        "sql": sql,
+    if sql.lower().startswith("explain"):
-    }
+        return
-    if query_name:
-        args["query_name"] = query_name
     return [
         {
             "href": datasette.urls.database(database)

tests/test_plugins.py

@@ -954,6 +954,8 @@ async def test_hook_table_actions(ds_client, table_or_view):
             "/fixtures/pragma_cache_size",
             "/fixtures?sql=explain+PRAGMA+cache_size%3B",
         ),
+        # Don't attempt to explain an explain
+        ("/fixtures?sql=explain+select+1", None),
     ),
 )
 async def test_hook_query_actions(ds_client, path, expected_url):
@@ -967,6 +969,9 @@ async def test_hook_query_actions(ds_client, path, expected_url):
     response = await ds_client.get(path)
     assert response.status_code == 200
     links = get_table_actions_links(response.text)
+    if expected_url is None:
+        assert links == []
+    else:
         assert links == [{"label": "Explain this query", "href": expected_url}]