exp: save: Add include_untracked.

Allow to include a list of potentially untracked files.
Covers the DVCLive use case where in the first run the generated files won't be tracked in Git yet.

dvc/commands/experiments/save.py

@@ -14,7 +14,9 @@ def run(self):
 
         try:
             ref = self.repo.experiments.save(
-                name=self.args.name, force=self.args.force
+                name=self.args.name,
+                force=self.args.force,
+                include_untracked=self.args.include_untracked,
             )
         except DvcException:
             logger.exception("failed to save experiment")
@@ -66,4 +68,12 @@ def add_parser(experiments_subparsers, parent_parser):
         ),
         metavar="<name>",
     )
+    save_parser.add_argument(
+        "-I",
+        "--include-untracked",
+        action="append",
+        default=[],
+        help="List of untracked files to include in the experiment.",
+        metavar="<pathspec>",
+    )
     save_parser.set_defaults(func=CmdExperimentsSave)

dvc/repo/experiments/executor/local.py

@@ -2,7 +2,7 @@
 import os
 from contextlib import ExitStack
 from tempfile import mkdtemp
-from typing import TYPE_CHECKING, Optional
+from typing import TYPE_CHECKING, List, Optional
 
 from funcy import cached_property
 from scmrepo.exceptions import SCMError as _SCMError
@@ -221,6 +221,7 @@ def save(
         cls,
         info: "ExecutorInfo",
         force: bool = False,
+        include_untracked: Optional[List[str]] = None,
     ) -> ExecutorResult:
         from dvc.repo import Repo
 
@@ -237,6 +238,8 @@ def save(
         try:
             stages = dvc.commit([], force=force)
             exp_hash = cls.hash_exp(stages)
+            if include_untracked:
+                dvc.scm.add(include_untracked)
             cls.commit(
                 dvc.scm,
                 exp_hash,

dvc/repo/experiments/save.py

@@ -15,6 +15,7 @@ def save(
     repo: "Repo",
     name: Optional[str] = None,
     force: bool = False,
+    include_untracked: Optional[List[str]] = None,
 ) -> Optional[str]:
     """Save the current workspace status as an experiment.
 
@@ -33,7 +34,10 @@ def save(
 
     entry = repo.experiments.new(queue=queue, name=name, force=force)
     executor = queue.init_executor(repo.experiments, entry)
-    save_result = executor.save(executor.info, force=force)
+
+    save_result = executor.save(
+        executor.info, force=force, include_untracked=include_untracked
+    )
     result = queue.collect_executor(repo.experiments, executor, save_result)
 
     exp_rev = first(result)

tests/func/experiments/test_save.py

@@ -49,22 +49,6 @@ def test_exp_save_overwrite_experiment(tmp_dir, dvc, scm, exp_stage):
     dvc.experiments.save(name="dummy", force=True)
 
 
-def test_exp_save_multiple(tmp_dir, dvc, scm):
-    baseline = scm.get_rev()
-    for i in range(2):
-        name = f"exp-{i}"
-        tmp_dir.gen({name: f"{name} content"})
-        dvc.experiments.save(name=name)
-
-    assert dvc.experiments.ls()[baseline] == ["exp-0", "exp-1"]
-
-    for i in range(2):
-        scm.reset(hard=True)
-        name = f"exp-{i}"
-        dvc.experiments.apply(name)
-        assert (tmp_dir / name).read_text() == f"{name} content"
-
-
 def test_exp_save_after_commit(tmp_dir, dvc, scm, exp_stage):
     baseline = scm.get_rev()
     dvc.experiments.save(name="exp-1")
@@ -85,4 +69,18 @@ def test_exp_save_with_staged_changes(tmp_dir, dvc, scm):
     dvc.experiments.save(name="exp")
 
     _, _, unstaged = scm.status()
-    assert "new_file" in unstaged
+    assert "new_file" in unstaged
+
+
+def test_exp_save_include_untracked(tmp_dir, dvc, scm, exp_stage):
+    new_file = tmp_dir / "new_file"
+    for i in range(2):
+        new_file.write_text(f"exp-{i}")
+        dvc.experiments.save(name=f"exp-{i}", include_untracked=["new_file"])
+
+    _, _, unstaged = scm.status()
+    assert "new_file" in unstaged
+    assert new_file.read_text() == f"exp-{i}"
+
+    dvc.experiments.apply("exp-0")
+    assert new_file.read_text() == "exp-0"

tests/unit/command/test_experiments.py

@@ -946,4 +946,6 @@ def test_experiments_save(dvc, scm, mocker):
 
     assert cmd.run() == 0
 
-    m.assert_called_once_with(cmd.repo, name="exp-name", force=True)
+    m.assert_called_once_with(
+        cmd.repo, name="exp-name", force=True, include_untracked=[]
+    )