'absolute' gives wrong result when CWD is '/'; crash in 'relative'

[jensjoha]

Find below a test that fails on Linux as well as a proposed fix.
Only tested on Linux.

diff --git a/lib/path.dart b/lib/path.dart
index 8e87c33..f4748cb 100644
--- a/lib/path.dart
+++ b/lib/path.dart
@@ -91,10 +91,12 @@ String get current {
     return _current;
   } else {
     var path = uri.toFilePath();
-    // Remove trailing '/' or '\'.
+    // Remove trailing '/' or '\' unless it is the only thing left
+    // (for instance the root on Linux).
     var lastIndex = path.length - 1;
     assert(path[lastIndex] == '/' || path[lastIndex] == '\\');
-    _current = path.substring(0, lastIndex);
+    if (lastIndex > 0) _current = path.substring(0, lastIndex);
+    else _current = path;
     return _current;
   }
 }
diff --git a/test/io_test.dart b/test/io_test.dart
index f15f82d..251d91c 100644
--- a/test/io_test.dart
+++ b/test/io_test.dart
@@ -55,4 +55,30 @@ main() {
       io.Directory.current = dir;
     }
   });
+
+  test('absolute works on root working directory', () {
+    var orgDir = io.Directory.current.path;
+    try {
+      while (io.Directory.current.parent != null &&
+          io.Directory.current.parent.path != io.Directory.current.path) {
+        io.Directory.current = io.Directory.current.parent;
+      }
+      var dir = io.Directory.current.path;
+
+      // "path.relative(path.absolute('foo/bar'), from: dir)" currently crashes
+      // on Linux.
+      expect(path.relative(path.absolute('foo/bar'), from: dir),
+          path.relative(path.absolute('foo/bar')));
+
+      // On Linux this currently compares "foo/bar" and "/foo/bar".
+      expect(path.normalize(path.absolute('foo/bar')),
+          equals(path.normalize(path.join(dir, '../foo/bar'))));
+
+      // On Linux this currently compares "foo/bar" and "/foo/bar".
+      expect(path.normalize(path.absolute('foo/bar')),
+          equals(path.normalize(path.context.join(dir, '../foo/bar'))));
+    } finally {
+      io.Directory.current = orgDir;
+    }
+  });
 }

[nex3]

Can you submit a pull request?

[jensjoha]

I have now tried. Hope I didn't step on any toes in the way I did it (I haven't used this workflow before).

[nex3]

You did great, thanks!