Add more input/output type annotations (#7532)

crates/nu-command/tests/main.rs

@@ -1,5 +1,5 @@
 use nu_command::create_default_context;
-use nu_protocol::engine::StateWorkingSet;
+use nu_protocol::{engine::StateWorkingSet, Category};
 use quickcheck_macros::quickcheck;
 
 mod commands;
@@ -49,6 +49,37 @@ fn signature_name_matches_command_name() {
     );
 }
 
+#[test]
+fn commands_declare_input_output_types() {
+    let ctx = crate::create_default_context();
+    let decls = ctx.get_decl_ids_sorted(true);
+    let mut failures = Vec::new();
+
+    for decl_id in decls {
+        let cmd = ctx.get_decl(decl_id);
+        let sig_name = cmd.signature().name;
+        let category = cmd.signature().category;
+
+        if matches!(category, Category::Deprecated | Category::Custom(_)) {
+            // Deprecated commands don't have to conform
+            // TODO: also upgrade the `--features dataframe` commands
+            continue;
+        }
+
+        if cmd.signature().input_output_types.is_empty() {
+            failures.push(format!(
+                "{sig_name} ({category:?}): No pipeline input/output type signatures found"
+            ));
+        }
+    }
+
+    assert!(
+        failures.is_empty(),
+        "Command missing type annotations:\n{}",
+        failures.join("\n")
+    );
+}
+
 #[test]
 fn no_search_term_duplicates() {
     let ctx = crate::create_default_context();