[lvgl] Add missing label dependency to qrcode, keyboard and tabview (#18387)

tests/component_tests/lvgl/config/keyboard_no_label.yaml

@@ -0,0 +1,32 @@
+esphome:
+  name: test-keyboard-no-label
+
+esp32:
+  board: esp32dev
+  framework:
+    type: esp-idf
+
+spi:
+  - id: spi_bus
+    clk_pin: GPIO18
+    mosi_pin: GPIO23
+
+display:
+  - platform: mipi_spi
+    spi_id: spi_bus
+    model: st7789v
+    id: tft_display
+    dimensions:
+      width: 240
+      height: 320
+    cs_pin: GPIO22
+    dc_pin: GPIO21
+    auto_clear_enabled: false
+    invert_colors: false
+    update_interval: never
+
+lvgl:
+  displays: tft_display
+  widgets:
+    - keyboard:
+        id: keyboard_widget

tests/component_tests/lvgl/config/qrcode_no_label.yaml

@@ -0,0 +1,34 @@
+esphome:
+  name: test-qrcode-no-label
+
+esp32:
+  board: esp32dev
+  framework:
+    type: esp-idf
+
+spi:
+  - id: spi_bus
+    clk_pin: GPIO18
+    mosi_pin: GPIO23
+
+display:
+  - platform: mipi_spi
+    spi_id: spi_bus
+    model: st7789v
+    id: tft_display
+    dimensions:
+      width: 240
+      height: 320
+    cs_pin: GPIO22
+    dc_pin: GPIO21
+    auto_clear_enabled: false
+    invert_colors: false
+    update_interval: never
+
+lvgl:
+  displays: tft_display
+  widgets:
+    - qrcode:
+        id: qr_widget
+        size: 100
+        text: "esphome.io"

tests/component_tests/lvgl/config/tabview_no_label.yaml

@@ -0,0 +1,35 @@
+esphome:
+  name: test-tabview-no-label
+
+esp32:
+  board: esp32dev
+  framework:
+    type: esp-idf
+
+spi:
+  - id: spi_bus
+    clk_pin: GPIO18
+    mosi_pin: GPIO23
+
+display:
+  - platform: mipi_spi
+    spi_id: spi_bus
+    model: st7789v
+    id: tft_display
+    dimensions:
+      width: 240
+      height: 320
+    cs_pin: GPIO22
+    dc_pin: GPIO21
+    auto_clear_enabled: false
+    invert_colors: false
+    update_interval: never
+
+lvgl:
+  displays: tft_display
+  widgets:
+    - tabview:
+        id: tabview_widget
+        tabs:
+          - name: "Tab 1"
+            id: tab_1

tests/component_tests/lvgl/test_widget_label_dependency.py

@@ -0,0 +1,32 @@
+"""Widgets whose LVGL C implementation creates or references labels
+internally (tab titles, key legends, the QR canvas fallback) must declare
+the label dependency in ``get_uses()``. Otherwise a config that contains
+no ``label`` widget of its own compiles LVGL without ``LV_USE_LABEL`` and
+fails at C compile time with undefined ``lv_label_*`` symbols.
+"""
+
+from __future__ import annotations
+
+from collections.abc import Callable
+from pathlib import Path
+
+import pytest
+
+from esphome.components.lvgl import defines as df
+
+
+@pytest.mark.parametrize(
+    "yaml_file",
+    [
+        "qrcode_no_label.yaml",
+        "keyboard_no_label.yaml",
+        "tabview_no_label.yaml",
+    ],
+)
+def test_label_less_config_enables_lv_use_label(
+    generate_main: Callable[[str | Path], str],
+    component_config_path: Callable[[str], Path],
+    yaml_file: str,
+) -> None:
+    generate_main(component_config_path(yaml_file))
+    assert "LV_USE_LABEL" in df.get_defines()