Apply review cleanups to the native ESP8266 toolchain

esphome/arduino8266/component.py

@@ -93,9 +93,9 @@ def _library_info(name: str, read_path: Path, data: dict) -> ArduinoLibrary:
             lib.include_dirs.append(path.resolve())
 
     lib.sources = sorted(
-        Path(f).resolve()
+        path.resolve()
         for f in collect_filtered_files(read_path / src_dir, src_filter)
-        if Path(f).suffix in SRC_FILE_EXTENSIONS
+        if (path := Path(f)).suffix in SRC_FILE_EXTENSIONS
     )
     return lib
 

esphome/arduino8266/toolchain.py

@@ -4,7 +4,6 @@ from __future__ import annotations
 
 import logging
 from pathlib import Path
-import re
 import subprocess
 
 from esphome.arduino8266 import framework
@@ -43,7 +42,7 @@ def run_compile(config: ConfigType, verbose: bool) -> int:
     from esphome.build_gen import arduino8266 as build_gen
 
     paths = framework.check_and_install(CORE.data[KEY_CORE][KEY_FRAMEWORK_VERSION])
-    build_gen.write_project(paths)
+    ninja_changed = build_gen.write_project(paths)
 
     build_dir = get_build_dir()
     env = framework.get_build_env(paths["toolchain_path"])
@@ -58,7 +57,10 @@ def run_compile(config: ConfigType, verbose: bool) -> int:
     if rc != 0:
         return rc
 
-    _write_compile_commands(paths["ninja_path"], build_dir, env)
+    # The compile database is a pure function of build.ninja; skip its
+    # regeneration (a ninja spawn plus MBs of text) on unchanged builds.
+    if ninja_changed or not (build_dir / "compile_commands.json").is_file():
+        _write_compile_commands(paths["ninja_path"], build_dir, env)
     _print_size_summary(build_dir, paths["toolchain_path"])
     get_idedata()
     return 0
@@ -86,16 +88,13 @@ def _write_compile_commands(
 def _parse_app_size(build_dir: Path) -> int | None:
     """Read the app flash budget (irom0_0_seg length) from the linker script."""
     from esphome.build_gen.arduino8266 import get_flash_ld_path
+    from esphome.components.esp8266.build_surgery import segment_length
 
-    appsize_re = re.compile(r"irom0_0_seg\s*:.+len\s*=\s*(0x[\da-f]+)", re.IGNORECASE)
     try:
         ld_text = get_flash_ld_path(build_dir).read_text(encoding="utf-8")
     except OSError:
         return None
-    for line in ld_text.splitlines():
-        if match := appsize_re.search(line):
-            return int(match.group(1), 16)
-    return None
+    return segment_length(ld_text, "irom0_0_seg")
 
 
 def _print_size_summary(build_dir: Path, toolchain_path: Path) -> None:

esphome/build_gen/arduino8266.py

@@ -373,8 +373,12 @@ def _common_parent(paths: list[Path]) -> Path:
     return Path(os.path.commonpath([str(p.parent) for p in paths]))
 
 
-def write_project(paths: dict[str, Path]) -> None:
-    """Write the ninja build for the current configuration."""
+def write_project(paths: dict[str, Path]) -> bool:
+    """Write the ninja build for the current configuration.
+
+    Returns True when ``build.ninja`` changed, so the caller can skip work
+    derived purely from it (the compile database) on unchanged builds.
+    """
     from esphome.arduino8266.component import resolve_libraries
     from esphome.arduino8266.framework import ccache_path
 
@@ -551,7 +555,7 @@ def write_project(paths: dict[str, Path]) -> None:
     lines.append("default firmware.factory.bin firmware.ota.bin")
     lines.append("")
 
-    write_file_if_changed(build_dir / "build.ninja", "\n".join(lines))
+    return write_file_if_changed(build_dir / "build.ninja", "\n".join(lines))
 
 
 def get_flash_ld_path(build_dir: Path) -> Path:

esphome/components/esp8266/boards.py

@@ -361,12 +361,30 @@ BOARDS = {
     },
 }
 
+"""
+ESP8266_BOARD_BUILD generate with:
+
+git clone https://github.com/platformio/platform-espressif8266
+python3 - <<'EOF'
+import json, glob, os
+for f in sorted(glob.glob("platform-espressif8266/boards/*.json")):
+    b = json.load(open(f))["build"]
+    extra = b["extra_flags"]
+    extra = extra.split() if isinstance(extra, str) else extra
+    defines = [
+        e[2:] for e in extra if e not in ("-DESP8266", "-DARDUINO_ARCH_ESP8266")
+    ]
+    entries = ", ".join(f'"{d}"' for d in defines) + ("," if len(defines) == 1 else "")
+    board = os.path.splitext(os.path.basename(f))[0]
+    print(f'    "{board}": {{"variant": "{b["variant"]}", "defines": ({entries})}},')
+EOF
+"""
+
 # Per-board Arduino core build metadata for the native (PlatformIO-free)
 # toolchain: the variant directory (supplies pins_arduino.h) and the
 # board-identity defines the PlatformIO builder passes via build.extra_flags.
 # -DESP8266 and -DARDUINO_ARCH_ESP8266 are shared by every board and added by
 # the generator; only the per-board defines are listed here.
-# Generated from platform-espressif8266 boards/*.json (see BOARDS note above).
 ESP8266_BOARD_BUILD = {
     "agruminolemon": {
         "variant": "agruminolemonv4",

esphome/components/esp8266/build_surgery.py

@@ -57,3 +57,12 @@ def apply_testing_memory_patches(content: str) -> str:
     content = _patch_segment_size(content, "iram1_0_seg", TESTING_IRAM_SIZE)
     content = _patch_segment_size(content, "dram0_0_seg", TESTING_DRAM_SIZE)
     return _patch_segment_size(content, "irom0_0_seg", TESTING_FLASH_SIZE)
+
+
+def segment_length(content: str, segment_name: str) -> int | None:
+    """Read a memory segment's length from linker script content."""
+    match = re.search(
+        rf"{segment_name}\s*:.+len\s*=\s*(0x[\da-fA-F]+)",
+        content,
+    )
+    return int(match.group(1), 16) if match else None