parametrization: Support keys of the dictionary to be interpolated (i…

…terative#4869)

dvc/parsing/context.py

@@ -297,7 +297,7 @@ def resolve(self, src, unwrap=True):
 
         resolve = rpartial(self.resolve, unwrap)
         if isinstance(src, Mapping):
-            return {key: resolve(value) for key, value in src.items()}
+            return dict(map(resolve, kv) for kv in src.items())
         elif isinstance(src, Seq):
             return type(src)(map(resolve, src))
         elif isinstance(src, str):

tests/unit/test_context.py

@@ -370,3 +370,12 @@ def test_node_value():
     assert context["lst"][1].value == 2
 
     assert context["foo"].value == "foo"
+
+
+def test_resolve_resolves_dict_keys():
+    d = {"dct": {"foo": "foobar", "persist": True}}
+
+    context = Context(d)
+    assert context.resolve({"${dct.foo}": {"persist": "${dct.persist}"}}) == {
+        "foobar": {"persist": True}
+    }