studio: Send message on start event.

- Bump `dvc-studio-client>=0.9.0,<1`

Part of #8870

dvc/repo/experiments/executor/base.py

@@ -501,6 +501,7 @@ class BaseExecutor(ABC):
             infofile,
             log_errors=log_errors,
             copy_paths=copy_paths,
+            message=message,
             **kwargs,
         ) as dvc:
             if auto_push:
@@ -631,6 +632,7 @@ class BaseExecutor(ABC):
         infofile: Optional[str] = None,
         log_errors: bool = True,
         copy_paths: Optional[List[str]] = None,
+        message: Optional[str] = None,
         **kwargs,
     ) -> Iterator["Repo"]:
         from dvc_studio_client.env import STUDIO_REPO_URL, STUDIO_TOKEN
@@ -668,6 +670,7 @@ class BaseExecutor(ABC):
                     params=to_studio_params(dvc.params.show()),
                     studio_token=run_env.get(STUDIO_TOKEN, None),
                     studio_repo_url=run_env.get(STUDIO_REPO_URL, None),
+                    message=message,
                 )
                 logger.debug("Running repro in '%s'", os.getcwd())
                 yield dvc

pyproject.toml

@@ -37,7 +37,7 @@ dependencies = [
     "dvc-data>=0.47.1,<0.48",
     "dvc-http>=2.29.0",
     "dvc-render>=0.3.1,<1",
-    "dvc-studio-client>=0.8.0,<1",
+    "dvc-studio-client>=0.9.0,<1",
     "dvc-task>=0.2.1,<1",
     "flatten_dict<1,>=0.4.1",
     "flufl.lock>=5",

tests/integration/test_studio_live_experiments.py

@@ -47,3 +47,37 @@ def test_post_to_studio(tmp_dir, dvc, scm, exp_stage, mocker, monkeypatch, tmp):
         "experiment_rev": exp_rev,
         "metrics": {"metrics.yaml": {"data": {"foo": 1}}},
     }
+
+
+@pytest.mark.parametrize("tmp", [True, False])
+def test_post_to_studio_custom_message(
+    tmp_dir, dvc, scm, exp_stage, mocker, monkeypatch, tmp
+):
+    valid_response = mocker.MagicMock()
+    valid_response.status_code = 200
+    mocked_post = mocker.patch("requests.post", return_value=valid_response)
+
+    monkeypatch.setenv(env.STUDIO_ENDPOINT, "https://0.0.0.0")
+    monkeypatch.setenv(env.STUDIO_REPO_URL, "STUDIO_REPO_URL")
+    monkeypatch.setenv(env.STUDIO_TOKEN, "STUDIO_TOKEN")
+
+    baseline_sha = scm.get_rev()
+    exp_rev = first(
+        dvc.experiments.run(
+            exp_stage.addressing, params=["foo=1"], tmp_dir=tmp, message="foo"
+        )
+    )
+    name = dvc.experiments.get_exact_name([exp_rev])[exp_rev]
+    assert mocked_post.call_count == 2
+
+    start_call = mocked_post.call_args_list[0]
+
+    assert start_call.kwargs["json"] == {
+        "type": "start",
+        "repo_url": "STUDIO_REPO_URL",
+        "baseline_sha": baseline_sha,
+        "name": name,
+        "params": {"params.yaml": {"foo": 1}},
+        "client": "dvc",
+        "message": "foo",
+    }