1 files changed, 28 insertions, 0 deletions
diff --git a/lib/tasks/submodules.rake b/lib/tasks/submodules.rake
new file mode 100644
index 000000000..426192713
--- /dev/null
+++ b/lib/tasks/submodules.rake
@@ -0,0 +1,28 @@
+
+namespace :submodules do
+
+    desc "Check the status of the project's submodules"
+    task :check => :environment do
+        commit_info = `git submodule status commonlib`
+        case commit_info[0,1]
+        when '+'
+            $stderr.puts "Error: Currently checked out submodule commit for commonlib"
+            $stderr.puts "does not match the commit expected by this version of Alaveteli."
+            $stderr.puts "You can update it with 'git submodule update'."
+            exit(1)
+        when '-'
+            $stderr.puts "Error: Submodule commonlib needs to be initialized."
+            $stderr.puts "You can do this by running 'git submodule update --init'."
+            exit(1)
+        when 'U'
+            $stderr.puts "Error: Submodule commonlib has merge conflicts."
+            $stderr.puts "You'll need to resolve these to run Alaveteli."
+            exit(1)
+        when ' '
+            exit(0)
+        else
+            raise "Unexpected status character in response to 'git submodule status commonlib': #{commit_info[0,1]}"
+        end
+    end
+
+end