add --preview flag to publish command

utils/pub/command_lish.dart

Index: utils/pub/command_lish.dart
===================================================================
--- utils/pub/command_lish.dart	(revision 18320)
+++ utils/pub/command_lish.dart	(working copy)
@@ -32,6 +32,9 @@
     var parser = new ArgParser();
     // TODO(nweiz): Use HostedSource.defaultUrl as the default value once we use
     // dart:io for HTTPS requests.
+    parser.addFlag('dry-run', abbr: 'n', negatable: false,
+        help: "Preview publishing the package\n" 
+              "Validate but do not publish the package");

[Bob Nystrom, 2013/02/12 01:00:41]

You can remove the "Preview..." line.

[keertip, 2013/02/12 05:20:20]

Done.

     parser.addOption('server', defaultsTo: 'https://pub.dartlang.org',
         help: 'The package server to which to upload this package');
     return parser;
@@ -100,9 +103,11 @@
 
     // Validate the package.
     return _validate(packageBytesFuture.then((bytes) => bytes.length))
-        .then((_) => packageBytesFuture).then(_publish);
+        .then((validate) {

[Bob Nystrom, 2013/02/12 01:00:41]

"validate" -> "isValid"

[keertip, 2013/02/12 05:20:20]

Done.

+           if (validate) return packageBytesFuture.then(_publish);
+           });

[Bob Nystrom, 2013/02/12 01:00:41]

The styling of this is a bit strange. How about:

return _validate(...
    .then((isValid) {
  if (isValid) return package...
});

[keertip, 2013/02/12 05:20:20]

Done.

   }
-
+  
   /// The basenames of files that are automatically excluded from archives.
   final _BLACKLISTED_FILES = const ['pubspec.lock'];
 
@@ -146,7 +151,7 @@
   }
 
   /// Validates the package. Throws an exception if it's invalid.
-  Future _validate(Future<int> packageSize) {
+  Future<bool> _validate(Future<int> packageSize) {
     return Validator.runAll(entrypoint, packageSize).then((pair) {
       var errors = pair.first;
       var warnings = pair.last;
@@ -158,6 +163,12 @@
             "http://pub.dartlang.org/doc/pub-lish.html.\n";

[Bob Nystrom, 2013/02/12 01:00:41]

Instead of throwing, just use log.error() to print the message then return
false.

[keertip, 2013/02/12 05:20:20]

With this change, publish will return with exitcode 0 even when there are erros
in the package. Would this be ok? Do we want to have a different exitcode to
indicate errors?

On 2013/02/12 01:00:41, Bob Nystrom wrote:

[Bob Nystrom, 2013/02/12 19:00:57]

Hmm. Good point. I think I'm OK with that for now at least.

       }
 
+      if (commandOptions['dry-run']){
+        var s = warnings.length == 1 ? '' : 's';
+        log.warning("Package has ${warnings.length} warning$s.");
+        return new Future.immediate(false);

[Bob Nystrom, 2013/02/12 01:00:41]

You don't need Future here, just "return false;"

[keertip, 2013/02/12 05:20:20]

Done.

+      }
+      
       var message = 'Looks great! Are you ready to upload your package';
 
       if (!warnings.isEmpty) {
@@ -167,6 +178,7 @@
 
       return confirm(message).then((confirmed) {
         if (!confirmed) throw "Package upload canceled.";

[Bob Nystrom, 2013/02/12 01:00:41]

Instead of throwing here, do log.message() then return false.

[keertip, 2013/02/12 05:20:20]

Done.

+        return new Future.immediate(true);

[Bob Nystrom, 2013/02/12 01:00:41]

Just "return true".

[keertip, 2013/02/12 05:20:20]

Done.

       });
     });
   }