Create binstubs for executables when activating a package.

sdk/lib/_internal/pub/lib/src/pubspec.dart

Index: sdk/lib/_internal/pub/lib/src/pubspec.dart
diff --git a/sdk/lib/_internal/pub/lib/src/pubspec.dart b/sdk/lib/_internal/pub/lib/src/pubspec.dart
index 7aa573503dbd3d1127a07f07703530f8d6c678e7..7d43b039d3a06dbcfbaa41002b1afab330f3718a 100644
--- a/sdk/lib/_internal/pub/lib/src/pubspec.dart
+++ b/sdk/lib/_internal/pub/lib/src/pubspec.dart
@@ -239,6 +239,59 @@ class Pubspec {
   bool _parsedPublishTo = false;
   String _publishTo;
 
+  /// The executables that should be placed on the user's PATH when this

[nweiz, 2014/09/15 22:57:18]

"placed on the user's PATH" isn't really accurate, since we're putting them in a
directory that probably won't be on the user's PATH by default.

+  /// package is globally activated.
+  ///
+  /// It is a map of strings to string. Each key is the name of the command
+  /// that will be placed on the user's PATH. The value is the name of the
+  /// .dart script (without extension) in the package's `bin` directory that
+  /// should be run for that command. Both key and value must be "simple"
+  /// strings: alphanumerics, underscores and hypens only. If a value is

[nweiz, 2014/09/15 22:57:18]

We don't otherwise restrict the name of executable scripts, do we? It seems a
little weird to do so here.

[Bob Nystrom, 2014/09/17 21:34:35]

The OS implicitly prevents you from putting path separators in a file name,
which was my initial concern here. Restricting it beyond that seemed like good
PATH hygiene to me. Since activating a package will put all of its executables
in the global namespace, I want them to be "nice" from the consumer's
perspective.

We can loosen these guidelines over time, but we can't tighten them, so I
figured we could start conservatively.

Also, it makes it clear that the ".dart" isn't needed for the script.

[nweiz, 2014/09/17 22:58:26]

I don't mind the restrictions on the binstub name, but it seems very strange to
me that the user could create an executable named "my.script.dart" and it would
work fine locally, work fine when run as a dependency executable, but fail if
they tried to make it a global executable, *even though they're aliasing it
anyway*.

[Bob Nystrom, 2014/09/18 19:17:52]

Done.

+  /// omitted, it is inferred to use the same name as the key.
+  Map<String, String> get executables {
+    if (_executables != null) return _executables;
+
+    var yaml = fields['executables'];
+    if (yaml == null) {
+      _executables = {};
+      return _executables;
+    }
+
+    if (yaml is! Map) {
+      _error('"executables" field must be a map.',
+          fields.nodes['executables'].span);
+    }
+
+    yaml.nodes.forEach((key, value) {
+      // Don't allow path separators or other stuff meaningful to the shell.
+      validateName(name, description) {
+        final validName = new RegExp(r"^[a-zA-Z0-9_-]+$");
+        if (!validName.hasMatch(name.value)) {
+          _error('"executables" $description may only contain letters, '
+              'numbers, hyphens and underscores.', name.span);
+        }
+      }
+
+      if (key.value is! String) {
+        _error('"executables" keys must be strings.', key.span);
+      }
+
+      validateName(key, "keys");
+
+      if (value.value == null) return;
+
+      if (value.value is! String) {
+        _error('"executables" values must be strings or null.', value.span);
+      }
+
+      validateName(value, "values");
+    });
+
+    _executables = yaml;
+    return _executables;
+  }
+  Map<String, String> _executables;
+  
   /// Whether the package is private and cannot be published.
   ///
   /// This is specified in the pubspec by setting "publish_to" to "none".