Suppress mod doc comment with empty [doc] attribute (#2254)

src/analyzer.rs

@@ -96,7 +96,7 @@ impl<'src> Analyzer<'src> {
             let mut doc_attr: Option<&str> = None;
             for attribute in attributes {
               if let Attribute::Doc(ref doc) = attribute {
-                doc_attr = doc.as_ref().map(|s| s.cooked.as_ref());
+                doc_attr = Some(doc.as_ref().map(|s| s.cooked.as_ref()).unwrap_or_default());
               } else {
                 return Err(name.token.error(InvalidAttribute {
                   item_kind: "Module",

src/subcommand.rs

@@ -452,7 +452,7 @@ impl Subcommand {
       signature_widths: &BTreeMap<&str, usize>,
     ) {
       if let Some(doc) = doc {
-        if doc.lines().count() <= 1 {
+        if !doc.is_empty() && doc.lines().count() <= 1 {
           print!(
             "{:padding$}{} {}",
             "",

tests/modules.rs

@@ -787,3 +787,20 @@ fn bad_module_attribute_fails() {
     .status(EXIT_FAILURE)
     .run();
 }
+
+#[test]
+fn empty_doc_attribute_on_module() {
+  Test::new()
+    .write("foo.just", "")
+    .justfile(
+      r#"
+        # Suppressed comment
+        [doc]
+        mod foo
+      "#,
+    )
+    .test_round_trip(false)
+    .arg("--list")
+    .stdout("Available recipes:\n    foo ...\n")
+    .run();
+}