Repository: iterative/dvc

Issue:
exp init: Revisit `type="dl"`
Once https://github.com/iterative/dvclive/issues/225 is solved, the `live` section will be deprecated in favor of using `metrics` and `plots`.

How should `exp init` behave when `type="dl"`?


Discussion:
Would it make sense for `type="dl"` to generate:

```yaml
stages:
  train:
    cmd: python train.py
    deps:
      - train.py
    metrics:
      - dvclive.json:
          cache: false
    plots:
      - dvclive/scalars:
          cache: false
```

Where `dvclive` would be replaced by the value passed to `--live` (if any) ?
cc @dberenbaum @skshetry 
@daavoo Would you be up to contribute this change?
> @daavoo Would you be up to contribute this change?

If you all agree on proposed workaround, yes
Sorry, I think I was too quick to approve this. Looking at it now, it seems more transparent to:

* Make `--live` optional and off by default for both `default` and `dl`. This makes `--type dl` seem less useful since it only differs by including checkpoints, but I don't think it's bad that we are unifying and simplifying.
* Make `--live` independent from whether to include `checkpoints: true`.
* Make `--live` mutually exclusive with `metrics` and `plots`.
* If `--live` and `--interactive` are both present, don't ask for `metrics` or `plots`.

This hopefully makes it a simple convenience to replace `metrics` and `plots` easily when using dvclive. 

Again, sorry for not catching this earlier.

Thoughts?

Resolving patch:
diff --git a/dvc/commands/experiments/init.py b/dvc/commands/experiments/init.py
--- a/dvc/commands/experiments/init.py
+++ b/dvc/commands/experiments/init.py
@@ -25,7 +25,6 @@ class CmdExperimentsInit(CmdBase):
     DEFAULT_METRICS = "metrics.json"
     DEFAULT_PARAMS = "params.yaml"
     PLOTS = "plots"
-    DVCLIVE = "dvclive"
     DEFAULTS = {
         "code": CODE,
         "data": DATA,
@@ -33,7 +32,6 @@ class CmdExperimentsInit(CmdBase):
         "metrics": DEFAULT_METRICS,
         "params": DEFAULT_PARAMS,
         "plots": PLOTS,
-        "live": DVCLIVE,
     }
 
     def run(self):
@@ -190,12 +188,11 @@ def add_parser(experiments_subparsers, parent_parser):
     )
     experiments_init_parser.add_argument(
         "--live",
-        help="Path to log dvclive outputs for your experiments"
-        f" (default: {CmdExperimentsInit.DVCLIVE})",
+        help="Path to log dvclive outputs for your experiments",
     )
     experiments_init_parser.add_argument(
         "--type",
-        choices=["default", "dl"],
+        choices=["default", "checkpoint"],
         default="default",
         help="Select type of stage to create (default: %(default)s)",
     )
diff --git a/dvc/repo/experiments/init.py b/dvc/repo/experiments/init.py
--- a/dvc/repo/experiments/init.py
+++ b/dvc/repo/experiments/init.py
@@ -36,7 +36,6 @@
     "params": "Path to a [b]parameters[/b] file",
     "metrics": "Path to a [b]metrics[/b] file",
     "plots": "Path to a [b]plots[/b] file/directory",
-    "live": "Path to log [b]dvclive[/b] outputs",
 }
 
 
@@ -79,15 +78,14 @@ def init_interactive(
     defaults: Dict[str, str],
     provided: Dict[str, str],
     validator: Callable[[str, str], Union[str, Tuple[str, str]]] = None,
-    live: bool = False,
     stream: Optional[TextIO] = None,
 ) -> Dict[str, str]:
     command_prompts = lremove(provided.keys(), ["cmd"])
     dependencies_prompts = lremove(provided.keys(), ["code", "data", "params"])
-    outputs_prompts = lremove(
-        provided.keys(),
-        ["models"] + (["live"] if live else ["metrics", "plots"]),
-    )
+    output_keys = ["models"]
+    if "live" not in provided:
+        output_keys.extend(["metrics", "plots"])
+    outputs_prompts = lremove(provided.keys(), output_keys)
 
     ret: Dict[str, str] = {}
     if "cmd" in provided:
@@ -200,21 +198,16 @@ def init(
     defaults = defaults.copy() if defaults else {}
     overrides = overrides.copy() if overrides else {}
 
-    with_live = type == "dl"
-
     if interactive:
         defaults = init_interactive(
             validator=partial(validate_prompts, repo),
             defaults=defaults,
-            live=with_live,
             provided=overrides,
             stream=stream,
         )
     else:
-        if with_live:
-            # suppress `metrics`/`plots` if live is selected, unless
-            # it is also provided via overrides/cli.
-            # This makes output to be a checkpoint as well.
+        if "live" in overrides:
+            # suppress `metrics`/`plots` if live is selected.
             defaults.pop("metrics", None)
             defaults.pop("plots", None)
         else:
@@ -251,7 +244,11 @@ def init(
         metrics_no_cache=compact([context.get("metrics"), live_metrics]),
         plots_no_cache=compact([context.get("plots"), live_plots]),
         force=force,
-        **{"checkpoints" if with_live else "outs": compact([models])},
+        **{
+            "checkpoints"
+            if type == "checkpoint"
+            else "outs": compact([models])
+        },
     )
 
     with _disable_logging(), repo.scm_context(autostage=True, quiet=True):


Test patch:
diff --git a/tests/func/experiments/test_init.py b/tests/func/experiments/test_init.py
--- a/tests/func/experiments/test_init.py
+++ b/tests/func/experiments/test_init.py
@@ -19,7 +19,6 @@ def test_init_simple(tmp_dir, scm, dvc, capsys):
             CmdExperimentsInit.CODE: {"copy.py": ""},
             "data": "data",
             "params.yaml": '{"foo": 1}',
-            "dvclive": {},
             "plots": {},
         }
     )
@@ -137,13 +136,11 @@ def test_init_interactive_when_no_path_prompts_need_to_be_asked(
                 "cmd": "cmd",
                 "deps": ["data", "src"],
                 "metrics": [
-                    {"dvclive.json": {"cache": False}},
                     {"metrics.json": {"cache": False}},
                 ],
                 "outs": ["models"],
                 "params": [{"params.yaml": None}],
                 "plots": [
-                    {os.path.join("dvclive", "scalars"): {"cache": False}},
                     {"plots": {"cache": False}},
                 ],
             }
@@ -313,26 +310,18 @@ def test_init_default(tmp_dir, scm, dvc, interactive, overrides, inp, capsys):
                 "data\n"
                 "params.yaml\n"
                 "models\n"
-                "dvclive\n"
                 "y"
             ),
         ),
         (
             True,
             {"cmd": "python script.py"},
-            io.StringIO(
-                "script.py\n"
-                "data\n"
-                "params.yaml\n"
-                "models\n"
-                "dvclive\n"
-                "y"
-            ),
+            io.StringIO("script.py\n" "data\n" "params.yaml\n" "models\n" "y"),
         ),
         (
             True,
             {"cmd": "python script.py", "models": "models"},
-            io.StringIO("script.py\ndata\nparams.yaml\ndvclive\ny"),
+            io.StringIO("script.py\ndata\nparams.yaml\ny"),
         ),
     ],
     ids=[
@@ -345,11 +334,12 @@ def test_init_default(tmp_dir, scm, dvc, interactive, overrides, inp, capsys):
 def test_init_interactive_live(
     tmp_dir, scm, dvc, interactive, overrides, inp, capsys
 ):
+    overrides["live"] = "dvclive"
+
     (tmp_dir / "params.yaml").dump({"foo": {"bar": 1}})
 
     init(
         dvc,
-        type="dl",
         interactive=interactive,
         defaults=CmdExperimentsInit.DEFAULTS,
         overrides=overrides,
@@ -361,7 +351,7 @@ def test_init_interactive_live(
                 "cmd": "python script.py",
                 "deps": ["data", "script.py"],
                 "metrics": [{"dvclive.json": {"cache": False}}],
-                "outs": [{"models": {"checkpoint": True}}],
+                "outs": ["models"],
                 "params": [{"params.yaml": None}],
                 "plots": [
                     {os.path.join("dvclive", "scalars"): {"cache": False}}
@@ -393,13 +383,13 @@ def test_init_interactive_live(
         (True, io.StringIO()),
     ],
 )
-def test_init_with_type_live_and_models_plots_provided(
+def test_init_with_type_checkpoint_and_models_plots_provided(
     tmp_dir, dvc, interactive, inp
 ):
     (tmp_dir / "params.yaml").dump({"foo": 1})
     init(
         dvc,
-        type="dl",
+        type="checkpoint",
         interactive=interactive,
         stream=inp,
         defaults=CmdExperimentsInit.DEFAULTS,
@@ -411,13 +401,11 @@ def test_init_with_type_live_and_models_plots_provided(
                 "cmd": "cmd",
                 "deps": ["data", "src"],
                 "metrics": [
-                    {"dvclive.json": {"cache": False}},
                     {"m": {"cache": False}},
                 ],
                 "outs": [{"models": {"checkpoint": True}}],
                 "params": [{"params.yaml": None}],
                 "plots": [
-                    {os.path.join("dvclive", "scalars"): {"cache": False}},
                     {"p": {"cache": False}},
                 ],
             }
@@ -445,6 +433,49 @@ def test_init_with_type_default_and_live_provided(
         defaults=CmdExperimentsInit.DEFAULTS,
         overrides={"cmd": "cmd", "live": "live"},
     )
+    assert (tmp_dir / "dvc.yaml").parse() == {
+        "stages": {
+            "train": {
+                "cmd": "cmd",
+                "deps": ["data", "src"],
+                "metrics": [
+                    {"live.json": {"cache": False}},
+                ],
+                "outs": ["models"],
+                "params": [{"params.yaml": None}],
+                "plots": [
+                    {os.path.join("live", "scalars"): {"cache": False}},
+                ],
+            }
+        }
+    }
+    assert (tmp_dir / "src").is_dir()
+    assert (tmp_dir / "data").is_dir()
+
+
+@pytest.mark.parametrize(
+    "interactive, inp",
+    [
+        (False, None),
+        (True, io.StringIO()),
+    ],
+)
+def test_init_with_live_and_metrics_plots_provided(
+    tmp_dir, dvc, interactive, inp
+):
+    (tmp_dir / "params.yaml").dump({"foo": 1})
+    init(
+        dvc,
+        interactive=interactive,
+        stream=inp,
+        defaults=CmdExperimentsInit.DEFAULTS,
+        overrides={
+            "cmd": "cmd",
+            "live": "live",
+            "metrics": "metrics.json",
+            "plots": "plots",
+        },
+    )
     assert (tmp_dir / "dvc.yaml").parse() == {
         "stages": {
             "train": {
diff --git a/tests/unit/command/test_experiments.py b/tests/unit/command/test_experiments.py
--- a/tests/unit/command/test_experiments.py
+++ b/tests/unit/command/test_experiments.py
@@ -690,7 +690,6 @@ def test_experiments_init(dvc, scm, mocker, capsys, extra_args):
             "metrics": "metrics.json",
             "params": "params.yaml",
             "plots": "plots",
-            "live": "dvclive",
         },
         overrides={"cmd": "cmd"},
         interactive=False,
@@ -727,7 +726,6 @@ def test_experiments_init_config(dvc, scm, mocker):
             "metrics": "metrics.json",
             "params": "params.yaml",
             "plots": "plots",
-            "live": "dvclive",
         },
         overrides={"cmd": "cmd"},
         interactive=False,
@@ -782,11 +780,11 @@ def test_experiments_init_cmd_not_required_for_interactive_mode(dvc, mocker):
     "extra_args, expected_kw",
     [
         (["--type", "default"], {"type": "default", "name": "train"}),
-        (["--type", "dl"], {"type": "dl", "name": "train"}),
+        (["--type", "checkpoint"], {"type": "checkpoint", "name": "train"}),
         (["--force"], {"force": True, "name": "train"}),
         (
-            ["--name", "name", "--type", "dl"],
-            {"name": "name", "type": "dl"},
+            ["--name", "name", "--type", "checkpoint"],
+            {"name": "name", "type": "checkpoint"},
         ),
         (
             [