Validate that a single library has the same name as the package.

utils/pub/validator/name.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library name_validator;
 
 import 'dart:io';
 
 import '../entrypoint.dart';
 import '../io.dart';
@@ skipping 13 matching lines @@
     : super(entrypoint);
 
   Future validate() {
     _checkName(entrypoint.root.name, 'Package name "${entrypoint.root.name}"');
 
     var libDir = join(entrypoint.root.dir, "lib");
     return dirExists(libDir).chain((libDirExists) {
       if (!libDirExists) return new Future.immediate([]);
       return listDir(libDir, recursive: true);
     }).transform((files) {
-      for (var file in files) {
-        file = relativeTo(file, libDir);
-        if (splitPath(file).contains("src")) continue;
-        if (path.extension(file) != '.dart') continue;
-        var libName = path.basenameWithoutExtension(file);
-        _checkName(libName, 'The name of "$file", "$libName",');
+      var libraries = files.map((file) => relativeTo(file, dirname(libDir)))
+          .filter((file) {
+        return !splitPath(file).contains("src") &&
+            path.extension(file) == '.dart';
+      });

[Bob Nystrom, 2012/12/13 19:52:32]

How about splitting this out into a separate function? It would be nice if there
was a single canonicalize place in code for "get the list of public libraries in
the package".

+
+      for (var library in libraries) {
+        var libName = path.basenameWithoutExtension(library);
+        _checkName(libName, 'The name of "$library", "$libName",');
+      }
+
+      if (libraries.length == 1) {
+        var libName = path.basenameWithoutExtension(libraries[0]);
+        if (libName == entrypoint.root.name) return;
+        warnings.add('The name of "$libraries[0]", "$libName", should match '
+            'the name of the package, "${entrypoint.root.name}".\n'
+            'This helps users know what library to import.');
       }
     });
   }
 
   void _checkName(String name, String description) {
     if (name == "") {
       errors.add("$description may not be empty.");
     } else if (!new RegExp(r"^[a-zA-Z0-9_]*$").hasMatch(name)) {
       errors.add("$description may only contain letters, numbers, and "
           "underscores.\n"
@@ skipping 17 matching lines @@
       builder
         ..add(source.substring(lastMatchEnd, match.start + 1))
         ..add("_")
         ..add(match.group(1).toLowerCase());
       lastMatchEnd = match.end;
     }
     builder.add(source.substring(lastMatchEnd));
     return builder.toString().toLowerCase();
   }
 }