From 84712c4acc79f1641c9fac6c9eef1e9a209393e2 Mon Sep 17 00:00:00 2001
From: Ruslan Kuprieiev <kupruser@gmail.com>
Date: Fri, 22 May 2020 02:58:26 +0300
Subject: [PATCH] dvc: don't write default values for cache/persist/metric
 (#3844)

---
 dvc/output/base.py     | 9 ++++++---
 tests/func/test_add.py | 7 ++++++-
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/dvc/output/base.py b/dvc/output/base.py
index edaf3bdce..61fee818a 100644
--- a/dvc/output/base.py
+++ b/dvc/output/base.py
@@ -271,7 +271,8 @@ class BaseOutput:
         if self.IS_DEPENDENCY:
             return ret
 
-        ret[self.PARAM_CACHE] = self.use_cache
+        if not self.use_cache:
+            ret[self.PARAM_CACHE] = self.use_cache
 
         if isinstance(self.metric, dict):
             if (
@@ -280,12 +281,14 @@ class BaseOutput:
             ):
                 del self.metric[self.PARAM_METRIC_XPATH]
 
-        ret[self.PARAM_METRIC] = self.metric
+        if self.metric:
+            ret[self.PARAM_METRIC] = self.metric
 
         if self.plot:
             ret[self.PARAM_PLOT] = self.plot
 
-        ret[self.PARAM_PERSIST] = self.persist
+        if self.persist:
+            ret[self.PARAM_PERSIST] = self.persist
 
         return ret
 
diff --git a/tests/func/test_add.py b/tests/func/test_add.py
index a9dafec81..eac3f96f5 100644
--- a/tests/func/test_add.py
+++ b/tests/func/test_add.py
@@ -44,7 +44,12 @@ def test_add(tmp_dir, dvc):
     assert len(stage.deps) == 0
     assert stage.cmd is None
     assert stage.outs[0].info["md5"] == md5
-    assert stage.md5 == "ee343f2482f53efffc109be83cc976ac"
+    assert stage.md5 == "411854a9fc55b3cebda28704e41b23b3"
+
+    assert load_stage_file("foo.dvc") == {
+        "md5": "411854a9fc55b3cebda28704e41b23b3",
+        "outs": [{"md5": "acbd18db4cc2f85cedef654fccc4a4d8", "path": "foo"}],
+    }
 
 
 def test_add_unicode(tmp_dir, dvc):