Rev package version as the extended source map format is a new feature.

lib/parser.dart

Index: lib/parser.dart
diff --git a/lib/parser.dart b/lib/parser.dart
index 492e6cf65030792b5062594ace3b748553f2305b..7721c6765616d46e707f79ecb5ebf5976fba37e4 100644
--- a/lib/parser.dart
+++ b/lib/parser.dart
@@ -205,13 +205,16 @@ class MappingBundle extends Mapping {
     if (uri == null) {
       throw new ArgumentError.notNull('uri');
     }
-    if (_mappings.containsKey(uri)) {
-      return _mappings[uri].spanFor(line, column, files: files, uri: uri);
-    }
-    // Fall back to looking up the source map on just the basename.
-    var name = path.basename(uri.toString());
-    if (_mappings.containsKey(name)) {
-      return _mappings[name].spanFor(line, column, files: files, uri: name);
+
+    // Fall back to looking up uri suffixes of decreasing length if the full

[Siggi Cherem (dart-lang), 2016/12/14 15:46:10]

Let's keep the first `if` from before (where you check containsKey(uri))

I know it's handled with `i=0`, but it is less work (no split/join) and it will
make it more clear that the suffix mechanism is a fallback.

[Jacob, 2016/12/14 18:49:42]

Changed the wording of the comment from fall back to 
"Find the longest suffix of the uri that matches the sourcemap"
That should make the existing code clearer.
In practice for typical web server uses of this code, the full uri
will never actually match the _mappings so there is no point 
in optimizing that case.

+    // uri does not match a source map.
+    var parts = path.split(uri);

[Siggi Cherem (dart-lang), 2016/12/14 15:46:10]

do we expect uri to contain any scheme? (do we need to first extract the path
out of the uri?)

[Jacob, 2016/12/14 18:49:42]

Good point.
path.split doesn't handle package: the way I need it to be handled.
Switched for manually finding split points instead of using path.split and
path.join
Added a few other tests to check for windows paths as well as package: paths.

+    for (var i = 0; i < parts.length; ++i) {
+      var candidate = path.joinAll(parts.skip(i));
+      if (_mappings.containsKey(candidate)) {
+        return _mappings[candidate]
+            .spanFor(line, column, files: files, uri: candidate);
+      }
     }
 
     // Note: when there is no source map for an uri, this behaves like an