exp run: Propagate .dvc/config.local in TempDirExecutor.

Closes #7254

dvc/repo/experiments/executor/local.py

@@ -4,6 +4,7 @@ from contextlib import ExitStack
 from tempfile import mkdtemp
 from typing import TYPE_CHECKING, Optional, Union
 
+from configobj import ConfigObj
 from funcy import retry
 from shortuuid import uuid
 
@@ -134,22 +135,29 @@ class TempDirExecutor(BaseLocalExecutor):
         merge_rev = self.scm.get_ref(EXEC_MERGE)
 
         self.scm.stash.apply(merge_rev)
+        self._update_config(repo.config.read("local"))
 
-    def _config(self, cache_dir):
+    def _update_config(self, update):
         local_config = os.path.join(
             self.root_dir,
             self.dvc_dir,
             "config.local",
         )
         logger.debug("Writing experiments local config '%s'", local_config)
-        with open(local_config, "w", encoding="utf-8") as fobj:
-            fobj.write(f"[cache]\n    dir = {cache_dir}")
+        if os.path.exists(local_config):
+            conf_obj = ConfigObj(local_config)
+            conf_obj.merge(update)
+        else:
+            conf_obj = ConfigObj(update)
+        if conf_obj:
+            with open(local_config, "wb") as fobj:
+                conf_obj.write(fobj)
 
     def init_cache(
         self, repo: "Repo", rev: str, run_cache: bool = True  # noqa: ARG002
     ):
         """Initialize DVC cache."""
-        self._config(repo.cache.repo.path)
+        self._update_config({"cache": {"dir": repo.cache.repo.path}})
 
     def cleanup(self, infofile: Optional[str] = None):
         super().cleanup(infofile)

tests/func/experiments/test_experiments.py

@@ -5,6 +5,7 @@ import stat
 from textwrap import dedent
 
 import pytest
+from configobj import ConfigObj
 from funcy import first
 
 from dvc.dvcfile import PROJECT_FILE
@@ -664,3 +665,21 @@ def test_experiment_no_commit(tmp_dir):
             repo.experiments.ls()
     finally:
         repo.close()
+
+
+def test_local_config_is_propagated_to_tmp(tmp_dir, scm, dvc):
+    with dvc.config.edit("local") as conf:
+        conf["cache"]["type"] = "hardlink"
+
+    stage = dvc.stage.add(
+        cmd="cat .dvc/config.local > file", name="foo", outs_no_cache=["file"]
+    )
+    scm.add_commit(["dvc.yaml"], message="add dvc.yaml")
+
+    results = dvc.experiments.run(stage.addressing, tmp_dir=True)
+    exp = first(results)
+    fs = scm.get_fs(exp)
+
+    with fs.open("file") as fobj:
+        conf_obj = ConfigObj(fobj)
+        assert conf_obj["cache"]["type"] == "hardlink"