Do not attempt deploy without changes.

Gruntfile.js

@@ -105,6 +105,14 @@ module.exports = function(grunt) {
           message: 'second deploy'
         },
         src: 'tmp/src'
+      },
+      null_deploy: {
+        options: {
+          url: '../repo',
+          tag: 'null',
+          message: 'null deploy, should not work'
+        },
+        src: 'tmp/src'
       }
     },
 
@@ -125,7 +133,7 @@ module.exports = function(grunt) {
 
   // Whenever the "test" task is run, first clean the "tmp" dir, then run this
   // plugin's task(s), then test the result.
-  grunt.registerTask('test', ['clean', 'init_repo', 'copy:first', 'git_deploy:first', 'clean:deploy', 'clean:test_build', 'copy:second', 'git_deploy:second', 'nodeunit']);
+  grunt.registerTask('test', ['clean', 'init_repo', 'copy:first', 'git_deploy:first', 'clean:deploy', 'clean:test_build', 'copy:second', 'git_deploy:second', 'clean:deploy', 'clean:test_build', 'copy:second', 'git_deploy:null_deploy', 'nodeunit']);
 
   // By default, run all tests.
   grunt.registerTask('default', ['test']);

tasks/git_deploy.js

@@ -97,21 +97,45 @@ module.exports = function(grunt) {
 
     var done = this.async();
 
+    // stage files for checkin
+
     var commands = [
       git(['clone', '-b', options.branch, options.url, '.' ]),
       git(['checkout', '-B', options.branch]),
-      copyIntoRepo( src, deployDir ),
-      git(['add', '--all']),
-      git(['commit', '--message=' + options.message ])
+      copyIntoRepo( src, deployDir )
     ];
 
-    if ( options.tag ) {
-      commands.push( git(['tag', '-a', options.tag, '-m', options.tagMessage]) );
-    }
-
-    commands.push( git(['push', '--prune', '--force', '--quiet', '--follow-tags', options.url, options.branch]) );
+    grunt.util.async.series(commands, function() {
+      spawn({ // determine if any files need to be checked in
+        cmd: 'git',
+        args: ['status'],
+        opts: {cwd: deployDir}
+      }, function(error, result, code) {
+        if(code == 0) {
+          if(result.stdout.indexOf('nothing to commit, working directory clean') < 0) { // files need to be checked in
+            commands = [
+               git(['add', '--all']),
+               git(['commit', '--message=' + options.message ])
+            ];
+
+            if ( options.tag ) {
+              commands.push( git(['tag', '-a', options.tag, '-m', options.tagMessage]) );
+            }
+
+            commands.push( git(['push', '--prune', '--force', '--quiet', '--follow-tags', options.url, options.branch]) );
+
+            grunt.util.async.series(commands, done);
+          } else { // files do not need to be checked in
+            grunt.log.writeln('Nothing for git_deploy to commit.');
+            done();
+          }
+        } else {
+          grunt.fail.warn('Error running "git status":' + result.stderr);
+          done();
+        }
+      });
+    });
 
-    grunt.util.async.series(commands, done);
 
   });
 };