Differentiate internal signature from external signature w.r.t. help (#5667)

* Differentiate internal signature from external signature w.r.t. help

* Add in the --help flag to default externs in default config

* Remove unusued build_extern

Co-authored-by: mjclements <clements.michael.james@gmail.com>

crates/nu-parser/src/parse_keywords.rs

@@ -54,7 +54,6 @@ pub fn parse_def_predecl(
         let (sig, ..) = parse_signature(working_set, spans[2], expand_aliases_denylist);
         let signature = sig.as_signature();
         working_set.exit_scope();
-
         if let (Some(name), Some(mut signature)) = (name, signature) {
             signature.name = name;
             let decl = signature.predeclare();
@@ -360,6 +359,7 @@ pub fn parse_def(
             let declaration = working_set.get_decl_mut(decl_id);
 
             signature.name = name.clone();
+            *signature = signature.add_help();
             signature.usage = usage;
 
             *declaration = signature.clone().into_block_command(block_id);

crates/nu-protocol/src/signature.rs

@@ -124,6 +124,23 @@ impl Eq for Signature {}
 
 impl Signature {
     pub fn new(name: impl Into<String>) -> Signature {
+        Signature {
+            name: name.into(),
+            usage: String::new(),
+            extra_usage: String::new(),
+            search_terms: vec![],
+            required_positional: vec![],
+            optional_positional: vec![],
+            rest_positional: None,
+            named: vec![],
+            is_filter: false,
+            creates_scope: false,
+            category: Category::Default,
+        }
+    }
+
+    // Add a default help option to a signature
+    pub fn add_help(mut self) -> Signature {
         // default help flag
         let flag = Flag {
             long: "help".into(),
@@ -134,24 +151,13 @@ impl Signature {
             var_id: None,
             default_value: None,
         };
-
-        Signature {
-            name: name.into(),
-            usage: String::new(),
-            extra_usage: String::new(),
-            search_terms: vec![],
-            required_positional: vec![],
-            optional_positional: vec![],
-            rest_positional: None,
-            named: vec![flag],
-            is_filter: false,
-            creates_scope: false,
-            category: Category::Default,
-        }
+        self.named.push(flag);
+        self
     }
 
+    // Build an internal signature with default help option
     pub fn build(name: impl Into<String>) -> Signature {
-        Signature::new(name.into())
+        Signature::new(name.into()).add_help()
     }
 
     /// Add a description to the signature

crates/nu-protocol/tests/test_signature.rs

@@ -31,13 +31,10 @@ fn test_signature_chained() {
 
     assert_eq!(signature.required_positional.len(), 1);
     assert_eq!(signature.optional_positional.len(), 1);
-    assert_eq!(signature.named.len(), 4); // The 3 above + help
+    assert_eq!(signature.named.len(), 3);
     assert!(signature.rest_positional.is_some());
-    assert_eq!(signature.get_shorts(), vec!['h', 'r', 'n']);
-    assert_eq!(
-        signature.get_names(),
-        vec!["help", "req-named", "named", "switch"]
-    );
+    assert_eq!(signature.get_shorts(), vec!['r', 'n']);
+    assert_eq!(signature.get_names(), vec!["req-named", "named", "switch"]);
     assert_eq!(signature.num_positionals(), 2);
 
     assert_eq!(