Support relative paths in path dependencies.

utils/pub/io.dart

Index: utils/pub/io.dart
diff --git a/utils/pub/io.dart b/utils/pub/io.dart
index 82614ca68af23db08cc7fa8d07b6d62a2d14e5b0..fcfba5cb9f391f1c9ebcf9b8f9bdb1abbe8b07e8 100644
--- a/utils/pub/io.dart
+++ b/utils/pub/io.dart
@@ -264,15 +264,23 @@ Future _attemptRetryable(Future callback()) {
   return makeAttempt(null);
 }
 
-/// Creates a new symlink that creates an alias from [from] to [to]. Returns a
-/// [Future] which completes to the symlink file (i.e. [to]).
+/// Creates a new symlink at path [symlink] that points to [target]. Returns a
+/// [Future] which completes to the symlink file.

[nweiz, 2013/02/15 23:09:24]

"to the path to the symlink file"; same below

[Bob Nystrom, 2013/02/16 00:09:57]

Done.

+///
+/// If [relative] is true, creates a symlink with a relative path from the
+/// symlink to the target. Otherwise, uses the [target] path unmodified.
 ///
 /// Note that on Windows, only directories may be symlinked to.
-Future<String> createSymlink(String from, String to) {
-  log.fine("Creating symlink ($to is a symlink to $from)");
+Future<String> createSymlink(String symlink, String target,

[nweiz, 2013/02/15 23:09:24]

I don't like the parameter reordering here. It should have the same order as "ln
-s".

[Bob Nystrom, 2013/02/16 00:09:57]

It's always going to be wrong for one OS. I found both orderings confusing but I
went this way because I think it's more consistent with other create___ methods
here, like createTextFile(path, content).

[nweiz, 2013/02/16 01:02:14]

The way it is now is wrong for all but one OS, and the OS it's right for is the
one that uses symlinks the least.
I'd rather be consistent with the most-commonly-used symlink utility. Don't
think of creating a symlink as creating a file as content; think of it as an
analogue to copying a file from one place to another. The argument order for "ln
-s" is the same as it would be if you were using "cp" instead.

[Bob Nystrom, 2013/02/16 01:19:03]

Done.

+    {bool relative: false}) {
+  if (relative) {
+    target = path.normalize(path.relative(target, from: path.dirname(symlink)));
+  }
+
+  log.fine("Creating $symlink pointing to $target");
 
   var command = 'ln';
-  var args = ['-s', from, to];
+  var args = ['-s', target, symlink];
 
   if (Platform.operatingSystem == 'windows') {
     // Call mklink on Windows to create an NTFS junction point. Only works on
@@ -281,24 +289,29 @@ Future<String> createSymlink(String from, String to) {
     // link (/d) because the latter requires some privilege shenanigans that
     // I'm not sure how to specify from the command line.
     command = 'mklink';
-    args = ['/j', to, from];
+    args = ['/j', symlink, target];
   }
 
   // TODO(rnystrom): Check exit code and output?
-  return runProcess(command, args).then((result) => to);
+  return runProcess(command, args).then((result) => symlink);
 }
 
-/// Creates a new symlink that creates an alias from the `lib` directory of
-/// package [from] to [to]. Returns a [Future] which completes to the symlink
-/// file (i.e. [to]). If [from] does not have a `lib` directory, this shows a
+/// Creates a new symlink that creates an alias at [symlink] that points to the
+/// `lib` directory of package [target]. Returns a [Future] which completes to
+/// the symlink file. If [target] does not have a `lib` directory, this shows a
 /// warning if appropriate and then does nothing.
-Future<String> createPackageSymlink(String name, String from, String to,
-    {bool isSelfLink: false}) {
+///
+/// If [relative] is true, creates a symlink with a relative path from the
+/// symlink to the target. Otherwise, uses the [target] path unmodified.
+Future<String> createPackageSymlink(String name, String symlink, String target,
+    {bool isSelfLink: false, bool relative: false}) {
   return defer(() {
     // See if the package has a "lib" directory.
-    from = path.join(from, 'lib');
+    target = path.join(target, 'lib');
     log.fine("Creating ${isSelfLink ? "self" : ""}link for package '$name'.");
-    if (dirExists(from)) return createSymlink(from, to);
+    if (dirExists(target)) {
+      return createSymlink(symlink, target, relative: relative);
+    }
 
     // It's OK for the self link (i.e. the root package) to not have a lib
     // directory since it may just be a leaf application that only has
@@ -308,7 +321,7 @@ Future<String> createPackageSymlink(String name, String from, String to,
                   'you will not be able to import any libraries from it.');
     }
 
-    return to;
+    return symlink;
   });
 }