[uart] Keep debug delimiters and event patterns in flash (#20109)

tests/component_tests/uart/config/debug_event_tables.yaml

@@ -0,0 +1,34 @@
+esphome:
+  name: test
+
+esp8266:
+  board: esp01_1m
+
+uart:
+  - id: uart_a
+    tx_pin: GPIO1
+    rx_pin: GPIO3
+    baud_rate: 9600
+    debug:
+      after:
+        delimiter: "\r\n"
+  - id: uart_b
+    tx_pin: GPIO2
+    baud_rate: 9600
+    debug:
+      after:
+        delimiter: [0x0D, 0x0A]
+
+event:
+  - platform: uart
+    uart_id: uart_a
+    name: Event A
+    event_types:
+      - "start": "*A#"
+      - "stop": [0x2A, 0x42, 0x23]
+  - platform: uart
+    uart_id: uart_a
+    name: Event B
+    event_types:
+      - "start": "*A#"
+      - "stop": [0x2A, 0x42, 0x23]

tests/component_tests/uart/test_debug_event_tables.py

@@ -0,0 +1,41 @@
+"""uart debug delimiters and uart event patterns live in shared PROGMEM tables."""
+
+from collections.abc import Callable
+from pathlib import Path
+import re
+
+import pytest
+
+from esphome.components.uart.event import validate_event_types
+import esphome.config_validation as cv
+
+
+def test_debug_delimiter_and_event_matchers_use_shared_tables(
+    generate_main: Callable[[str | Path], str],
+    component_config_path: Callable[[str], Path],
+) -> None:
+    main_cpp = generate_main(component_config_path("debug_event_tables.yaml"))
+
+    # "\r\n" and [0x0D, 0x0A] are the same bytes, so both debuggers share one table
+    delimiters = re.findall(r"->set_after_delimiter\((\w+), 2\);", main_cpp)
+    assert len(delimiters) == 2
+    assert delimiters[0] == delimiters[1]
+    assert "add_delimiter_byte" not in main_cpp
+
+    # Both events have the same patterns, so they share the byte tables and the matcher table
+    patterns = re.findall(r"static constexpr uint8_t uart_event_match\w*\[\]", main_cpp)
+    assert len(patterns) == 2
+    calls = re.findall(r"->set_matchers\((\w+), 2, 3\);", main_cpp)
+    assert len(calls) == 2
+    assert calls[0] == calls[1]
+    assert main_cpp.count("static constexpr uart::UARTEventMatcher") == 1
+    assert "add_event_matcher" not in main_cpp
+
+
+def test_event_string_patterns_are_utf8_bytes() -> None:
+    assert validate_event_types([{"euro": "€"}]) == [("euro", [0xE2, 0x82, 0xAC])]
+
+
+def test_event_types_count_is_capped() -> None:
+    with pytest.raises(cv.Invalid, match="at most 65535 entries"):
+        validate_event_types([{f"e{i}": "x"} for i in range(0x10000)])