Merge pull request #1650 from mroutis/fix-1634

stage: always reproduce callback stages

dvc/stage.py

@@ -657,7 +657,7 @@ class Stage(object):
         else:
             logger.info("Running command:\n\t{}".format(self.cmd))
             if not dry:
-                if self._already_cached():
+                if not self.is_callback and self._already_cached():
                     self.checkout()
                 else:
                     self._run()

tests/test_repro.py

@@ -1277,3 +1277,19 @@ class TestReproNoCommit(TestRepro):
         ret = main(["repro", self.file1_stage, "--no-commit"])
         self.assertEqual(ret, 0)
         self.assertEqual(len(os.listdir(self.dvc.cache.local.cache_dir)), 0)
+
+
+class TestReproAlreadyCached(TestRepro):
+    def test(self):
+        first_out = self.dvc.run(
+            fname="random.dvc",
+            deps=[],
+            outs=["random.txt"],
+            cmd='python -c "{}" > random.txt'.format(
+                "from random import random; print(random())"
+            ),
+        ).outs[0]
+
+        second_out = self.dvc.reproduce(target="random.dvc")[0].outs[0]
+
+        self.assertNotEqual(first_out.checksum, second_out.checksum)