[config] Add --no-defaults flag to config command (#16718)

esphome/__main__.py

@@ -1428,7 +1428,16 @@ def command_wizard(args: ArgsProtocol) -> int | None:
 def command_config(args: ArgsProtocol, config: ConfigType) -> int | None:
     from esphome import yaml_util
 
-    if not CORE.verbose:
+    if getattr(args, "no_defaults", False):
+        user_config = getattr(config, "user_config", None)
+        if user_config is None:
+            _LOGGER.warning(
+                "--no-defaults requested but the user-only config snapshot is "
+                "unavailable; falling back to the validated configuration."
+            )
+        else:
+            config = user_config
+    elif not CORE.verbose:
         config = strip_default_ids(config)
     output = yaml_util.dump(config, args.show_secrets)
     if not args.show_secrets:
@@ -2152,6 +2161,12 @@ def parse_args(argv):
     parser_config.add_argument(
         "--show-secrets", help="Show secrets in output.", action="store_true"
     )
+    parser_config.add_argument(
+        "--no-defaults",
+        help="Only output the user-supplied configuration without "
+        "schema defaults applied.",
+        action="store_true",
+    )
 
     parser_config_hash = subparsers.add_parser(
         "config-hash", help="Calculate the hash of the configuration."

esphome/config.py

@@ -3,6 +3,7 @@ from __future__ import annotations
 import abc
 from contextlib import contextmanager
 import contextvars
+import copy
 import functools
 import heapq
 import logging
@@ -168,6 +169,11 @@ class Config(OrderedDict, fv.FinalValidateConfig):
         self.output_paths: list[tuple[ConfigPath, str]] = []
         # A list of components ids with the config path
         self.declare_ids: list[tuple[core.ID, ConfigPath]] = []
+        # Snapshot of the user's configuration after substitutions/packages/
+        # extend-remove resolution but before any schema validation defaults
+        # are applied. Populated by validate_config; used by `esphome config
+        # --no-defaults` to emit only the user-supplied keys.
+        self.user_config: ConfigType | None = None
         self._data = {}
         # Store pending validation tasks (in heap order)
         self._validation_tasks: list[_ValidationStepTask] = []
@@ -1076,6 +1082,15 @@ def validate_config(
         )
         return result
 
+    # Snapshot the user's config before any schema validation defaults are
+    # applied. preload_core_config and later validation steps rewrite entries
+    # in-place with defaulted values; deep-copying here preserves the
+    # user-supplied keys for `esphome config --no-defaults`.
+    result.user_config = copy.deepcopy(config)
+    if substitutions is not None:
+        result.user_config[CONF_SUBSTITUTIONS] = copy.deepcopy(substitutions)
+        result.user_config.move_to_end(CONF_SUBSTITUTIONS, last=False)
+
     # 2. Load partial core config
     import esphome.core.config as core_config
 

tests/unit_tests/test_main.py

@@ -471,6 +471,88 @@ def test_command_config__show_secrets_skips_redaction(
     assert "\\033[8m" not in output
 
 
+def test_command_config__no_defaults_dumps_user_snapshot(
+    tmp_path: Path, capfd: CaptureFixture[str]
+) -> None:
+    """``--no-defaults`` dumps ``config.user_config`` instead of the
+    validated config, so schema defaults don't leak into the output."""
+    from esphome.config import Config
+
+    setup_core(tmp_path=tmp_path, config={"esphome": {"name": "test"}})
+    args = MockArgs()
+    args.show_secrets = True
+    args.no_defaults = True
+
+    validated = Config()
+    validated["esphome"] = {"name": "test", "build_path": "build/test"}
+    validated["wifi"] = {"ssid": "MyNet", "reboot_timeout": "15min"}
+    validated.user_config = {
+        "esphome": {"name": "test"},
+        "wifi": {"ssid": "MyNet"},
+    }
+
+    result = command_config(args, validated)
+
+    assert result == 0
+    output = capfd.readouterr().out
+    assert "ssid: MyNet" in output
+    # Defaults present on the validated config must not appear.
+    assert "reboot_timeout" not in output
+    assert "build_path" not in output
+
+
+def test_command_config__no_defaults_warns_when_snapshot_missing(
+    tmp_path: Path,
+    capfd: CaptureFixture[str],
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """If the snapshot is unavailable (e.g. a plain dict was passed in),
+    ``--no-defaults`` logs a warning and falls back to the input config."""
+    setup_core(tmp_path=tmp_path, config={"esphome": {"name": "test"}})
+    args = MockArgs()
+    args.show_secrets = True
+    args.no_defaults = True
+
+    with caplog.at_level(logging.WARNING, logger="esphome.__main__"):
+        result = command_config(args, {"wifi": {"ssid": "MyNet"}})
+
+    assert result == 0
+    output = capfd.readouterr().out
+    assert "ssid: MyNet" in output
+    assert any(
+        "user-only config snapshot is unavailable" in rec.message
+        for rec in caplog.records
+    )
+
+
+def test_command_config__no_defaults_skips_strip_default_ids(
+    tmp_path: Path, capfd: CaptureFixture[str]
+) -> None:
+    """When ``--no-defaults`` is set, ``strip_default_ids`` isn't run --
+    the user snapshot is already free of schema-injected IDs."""
+    from esphome.config import Config
+
+    setup_core(tmp_path=tmp_path, config={"esphome": {"name": "test"}})
+    args = MockArgs()
+    args.show_secrets = True
+    args.no_defaults = True
+
+    validated = Config()
+    validated["sensor"] = [{"name": "x", "id": "auto_generated"}]
+    validated.user_config = {"sensor": [{"name": "x"}]}
+
+    with patch(
+        "esphome.__main__.strip_default_ids", side_effect=AssertionError
+    ) as mock_strip:
+        result = command_config(args, validated)
+
+    assert result == 0
+    mock_strip.assert_not_called()
+    output = capfd.readouterr().out
+    assert "name: x" in output
+    assert "auto_generated" not in output
+
+
 def test_choose_upload_log_host_with_string_default() -> None:
     """Test with a single string default device."""
     setup_core()

tests/unit_tests/test_substitutions.py

@@ -361,6 +361,47 @@ def test_validate_config_without_command_line_substitutions_maintains_ordered_di
     assert result[CONF_SUBSTITUTIONS]["var2"] == "value2"
 
 
+def test_validate_config_captures_user_config_snapshot(tmp_path: Path) -> None:
+    """validate_config stores a deep copy of the user's config -- with
+    substitutions re-added and no schema defaults applied -- on
+    ``result.user_config`` for ``esphome config --no-defaults``.
+    """
+    test_config = _get_test_minimal_valid_config(tmp_path)
+
+    result = config_module.validate_config(test_config, None)
+
+    # Snapshot is populated.
+    assert result.user_config is not None
+    # Substitutions are re-added and appear first.
+    assert list(result.user_config.keys())[0] == CONF_SUBSTITUTIONS
+    assert result.user_config[CONF_SUBSTITUTIONS]["var1"] == "value1"
+    # User-supplied keys are present without schema-default fields like
+    # ``build_path`` (which preload_core_config injects on the validated
+    # result's esphome section).
+    assert result.user_config["esphome"] == {"name": "test_device"}
+    assert "build_path" not in result.user_config["esphome"]
+    assert "min_version" not in result.user_config["esphome"]
+    assert result.user_config["esp32"] == {"board": "esp32dev"}
+
+
+def test_validate_config_user_config_snapshot_is_deep_copy(tmp_path: Path) -> None:
+    """The snapshot is independent of subsequent mutations to the result
+    config -- preload_core_config rewrites ``esphome:`` in place, but the
+    snapshot keeps the user's literal block.
+    """
+    test_config = _get_test_minimal_valid_config(tmp_path)
+
+    result = config_module.validate_config(test_config, None)
+
+    assert result.user_config is not None
+    # preload_core_config injected build_path onto the validated config.
+    assert "build_path" in result["esphome"]
+    # The snapshot was taken before that and is unaffected.
+    assert "build_path" not in result.user_config["esphome"]
+    # And the two are not aliased.
+    assert result["esphome"] is not result.user_config["esphome"]
+
+
 def test_merge_config_preserves_ordered_dict() -> None:
     """Test that merge_config preserves OrderedDict type.