Qualify library names in packages

lib/src/compiler/code_generator.dart

Index: lib/src/compiler/code_generator.dart
diff --git a/lib/src/compiler/code_generator.dart b/lib/src/compiler/code_generator.dart
index 2c19b39ef6f2c7ac0a9af6e10978145d953ec503..608a896307951c205cf6f07e01168d5dd0b8212c 100644
--- a/lib/src/compiler/code_generator.dart
+++ b/lib/src/compiler/code_generator.dart
@@ -3761,6 +3761,17 @@ class CodeGenerator extends GeneralizingAstVisitor
 /// This never uses the library's name (the identifier in the `library`
 /// declaration) as it doesn't have any meaningful rules enforced.
 String jsLibraryName(LibraryElement library) {
+  var uri = library.source.uri;
+  if (uri.scheme == 'package') {
+    // Strip the package name.
+    // TODO(vsm): This is not unique if an escaped '/'appears in a filename.
+    // E.g., "foo/bar.dart" and "foo$47bar.dart" would collide.
+    var packageRelativePath = uri.pathSegments.skip(1).join('/');

[Jennifer Messerly, 2016/04/26 22:59:33]

Yeah in general it's not going to be unique.

Also, surely we do not want $47 in our API signatures. :)

I think the problem is `pathToJSIdentifier`... it's not designed to be run
except on the file name.


So last time we had discussed this in:
https://github.com/dart-lang/dev_compiler/issues/504#issuecomment-211561183

... we were going to have non-top-level libs to use some scheme where they're
kind of hidden.

Library name is used in two distinct ways:
A. as a local variable in the module
B. as an export/import member of the module

Only B needs to worry about conflicts.


So something like:

// import
import { unittest, _libs } from 'unittest'

// note: this is a temp, conflicts if any will be automagically handled,
// so we can use any friendly name here. src_matchers would work too.
const matchers = _libs['src/matchers'];


// if we're exporting
export const _libraries = {
  'src/matchers': matchers,
  //...
}

... that would be a generally safe scheme, we only have one special name
(_libraries).

That seems like the route to go for a real fix.

If we just want a quick hack, maybe we could use "_", which would not look too
bad in the code.

+    return pathToJSIdentifier(packageRelativePath);
+  }
+  // TODO(vsm): This is not unique, but we're not in
+  // a package.  We need a mechanism for creating a unique library
+  // name.
   return pathToJSIdentifier(library.source.uri.pathSegments.last);
 }