Merge pull request #279 from datalad/issue-275-aggregate-path-constra…

…ints

Fix number of required path arguments in meta-aggregate interface

.appveyor.yml

@@ -52,6 +52,12 @@ shallow_clone: false
 # Do not build a branch, if a PR with the branch exists
 skip_branch_with_pr: true
 
+# Outside of PRs, build only these branches:
+branches:
+  only:
+    - master
+    - maint_0.4
+
 
 environment:
   # Do not use `image` as a matrix dimension, to have fine-grained control over

datalad_metalad/aggregate.py

@@ -160,7 +160,7 @@ class Aggregate(Interface):
             doc=r"""
             PATH to a sub-dataset whose metadata shall be aggregated into
             the topmost dataset (ROOT_DATASET)""",
-            nargs="*",
+            nargs="+",
             constraints=EnsureStr() | EnsureNone()))
 
     @staticmethod