Quote number-like device names in generated YAML

esphome_device_builder/helpers/device_yaml/_generation.py

@@ -169,7 +169,7 @@ def generate_adoption_yaml(
     splices *api_encryption_key* in; ``None`` leaves the device's own key alone.
     """
     lines: list[str] = ["substitutions:"]
-    lines.append(f"  name: {name}")
+    lines.append(f"  name: {_safe_yaml_scalar(name)}")
     if friendly_name:
         lines.append(f"  friendly_name: {_safe_yaml_scalar(friendly_name)}")
     lines.append("")
@@ -216,14 +216,12 @@ def generate_device_yaml(
     # Board reference comment so users can find the source manifest
     lines: list[str] = [*_board_header_lines(board)]
 
-    # ESPHome core. ``name`` arrives already slug-safe (see
-    # ``mutations_create``), but ``friendly_name`` is raw user
-    # input that may contain ``:``, ``#``, leading indicators, or
-    # other YAML metacharacters — route it through the safe-scalar
-    # renderer so a label like ``Bedroom #2`` doesn't truncate at
-    # the comment marker on round trip.
+    # ESPHome core. Both values go through the safe-scalar renderer:
+    # an all-digit ``name`` would parse back as an int, and a
+    # ``friendly_name`` like ``Bedroom #2`` would truncate at the
+    # comment marker.
     lines.append("esphome:")
-    lines.append(f"  name: {name}")
+    lines.append(f"  name: {_safe_yaml_scalar(name)}")
     lines.append(f"  friendly_name: {_safe_yaml_scalar(friendly_name)}")
     lines.append("")
 
@@ -496,7 +494,7 @@ def generate_minimal_stub_yaml(
     about to edit.
     """
     header = (
-        f"esphome:\n  name: {name}\n"
+        f"esphome:\n  name: {_safe_yaml_scalar(name)}\n"
         f"  friendly_name: {_safe_yaml_scalar(friendly_name)}\n\n"
         "# Replace this with your actual platform if you aren't using ESP32.\n"
         "esp32:\n  board: esp32dev\n\n"

tests/controllers/devices/test_create.py

@@ -514,6 +514,23 @@ async def test_create_device_quotes_friendly_name_with_yaml_metachars(
     assert storage.friendly_name == "Bedroom #2: lamp"
 
 
+@pytest.mark.usefixtures("stub_create_device_metadata_helpers")
+async def test_create_device_quotes_all_digit_name(
+    tmp_path: Path, make_controller: MakeControllerFactory
+) -> None:
+    """An all-digit name is written quoted so it parses back as a string."""
+    ctrl = make_controller(tmp_path, with_state_monitor=True, with_boards=True)
+    boards = StubBoardLookups(ctrl)
+    boards.find_by_pio_board_returns(None)
+    boards.find_by_platform_variant_returns(None)
+
+    result = await ctrl.create_device(name="8266")
+
+    assert result.configuration == "8266.yaml"
+    content = (tmp_path / "8266.yaml").read_text("utf-8")
+    assert '  name: "8266"\n' in content
+
+
 @pytest.mark.usefixtures("stub_create_device_metadata_helpers")
 async def test_create_device_rejects_name_with_no_hostname_safe_characters(
     tmp_path: Path, make_controller: MakeControllerFactory

tests/test_device_yaml.py

@@ -146,6 +146,27 @@ def test_generate_minimal_stub_yaml_has_required_blocks() -> None:
     assert "\ncaptive_portal:\n" in out
 
 
+@pytest.mark.parametrize("name", ["8266", "0x1f", "017", "esp-8266"])
+def test_generators_emit_name_as_string(name: str) -> None:
+    """Every generator's ``name`` parses back as a string, even when number-like."""
+    stub = generate_minimal_stub_yaml(name, "Lamp", wifi_secrets_available=False)
+    full = generate_device_yaml(
+        name, "Lamp", _make_esp32_board(), ssid="", psk="", wifi_secrets_available=False
+    )
+    adopt = generate_adoption_yaml(
+        name,
+        "Lamp",
+        "k",
+        "github://x/y.yaml@main",
+        wifi_secrets_available=False,
+        api_encryption_key=None,
+    )
+    for text, section in ((stub, "esphome"), (full, "esphome"), (adopt, "substitutions")):
+        parsed = yaml_util.parse_yaml(Path("x.yaml"), text)[section]["name"]
+        assert isinstance(parsed, str)
+        assert parsed == name
+
+
 def test_generate_minimal_stub_yaml_emits_per_device_encryption_key() -> None:
     """API encryption key is freshly generated each call.