[logger] Fix ESP8266 crash with VERY_VERBOSE log level (#14980)

esphome/components/logger/__init__.py

@@ -56,6 +56,7 @@ from esphome.const import (
     PlatformFramework,
 )
 from esphome.core import CORE, CoroPriority, Lambda, coroutine_with_priority
+from esphome.types import ConfigType
 
 CODEOWNERS = ["@esphome/core"]
 logger_ns = cg.esphome_ns.namespace("logger")
@@ -323,12 +324,11 @@ CONFIG_SCHEMA = cv.All(
 )
 
 
-@coroutine_with_priority(CoroPriority.DIAGNOSTICS)
-async def to_code(config):
-    baud_rate = config[CONF_BAUD_RATE]
+@coroutine_with_priority(CoroPriority.EARLY_INIT)
+async def to_code(config: ConfigType) -> None:
+    baud_rate: int = config[CONF_BAUD_RATE]
     level = config[CONF_LEVEL]
     CORE.data.setdefault(CONF_LOGGER, {})[CONF_LEVEL] = level
-    initial_level = LOG_LEVELS[config.get(CONF_INITIAL_LEVEL, level)]
     tx_buffer_size = config[CONF_TX_BUFFER_SIZE]
     cg.add_define("ESPHOME_LOGGER_TX_BUFFER_SIZE", tx_buffer_size)
     log = cg.new_Pvariable(
@@ -347,10 +347,23 @@ async def to_code(config):
                 HARDWARE_UART_TO_UART_SELECTION[config[CONF_HARDWARE_UART]]
             )
         )
-    # pre_setup() must be called before init_log_buffer() because
-    # init_log_buffer() calls disable_loop() which may log at VV level,
-    # and global_logger must be set before any logging occurs.
+    # pre_setup() sets global_logger and must run before any other code
+    # that may call ESP_LOG* (e.g. setup_preferences contains ESP_LOGVV).
     cg.add(log.pre_setup())
+    initial_level = LOG_LEVELS[config.get(CONF_INITIAL_LEVEL, level)]
+    cg.add(log.set_log_level(initial_level))
+
+    # Schedule the rest of logger setup at DIAGNOSTICS priority, after
+    # Application is constructed (CORE priority) but before most components.
+    CORE.add_job(_late_logger_init, config)
+
+
+@coroutine_with_priority(CoroPriority.DIAGNOSTICS)
+async def _late_logger_init(config: ConfigType) -> None:
+    """Finish logger setup after Application is constructed."""
+    log = await cg.get_variable(config[CONF_ID])
+    level = config[CONF_LEVEL]
+    baud_rate: int = config[CONF_BAUD_RATE]
     if CORE.is_esp32 or CORE.is_libretiny or CORE.is_nrf52:
         task_log_buffer_size = config[CONF_TASK_LOG_BUFFER_SIZE]
         if task_log_buffer_size > 0:
@@ -363,8 +376,6 @@ async def to_code(config):
         cg.add_define("USE_ESPHOME_TASK_LOG_BUFFER")
         cg.add(log.init_log_buffer(64))  # Fixed 64 slots for host
 
-    cg.add(log.set_log_level(initial_level))
-
     # Enable runtime tag levels if logs are configured or explicitly enabled
     logs_config = config[CONF_LOGS]
     if logs_config or config[CONF_RUNTIME_TAG_LEVELS]:

esphome/core/config.py

@@ -587,7 +587,9 @@ async def _add_looping_components() -> None:
 
 @coroutine_with_priority(CoroPriority.CORE)
 async def to_code(config: ConfigType) -> None:
-    cg.add_global(cg.global_ns.namespace("esphome").using)
+    # using namespace esphome is hardcoded in writer.py to guarantee it
+    # precedes all variable declarations regardless of coroutine priority.
+
     # These can be used by user lambdas, put them to default scope
     cg.add_global(cg.RawExpression("using std::isnan"))
     cg.add_global(cg.RawExpression("using std::min"))

esphome/coroutine.py

@@ -63,7 +63,13 @@ class CoroPriority(enum.IntEnum):
     resolution during code generation.
     """
 
-    # Platform initialization - must run first
+    # Early init - runs before platform init and before Application exists.
+    # Currently used only to connect logging so ESP_LOG* calls work
+    # immediately in all subsequent phases.
+    # Examples: logger (1100)
+    EARLY_INIT = 1100
+
+    # Platform initialization
     # Examples: esp32, esp8266, rp2040
     PLATFORM = 1000
 
@@ -83,7 +89,7 @@ class CoroPriority(enum.IntEnum):
     CORE = 100
 
     # Diagnostic and debugging systems
-    # Examples: logger (90)
+    # Examples: debug component (90)
     DIAGNOSTICS = 90
 
     # Status and monitoring systems

esphome/writer.py

@@ -381,7 +381,10 @@ def write_cpp(code_s):
         code_format = CPP_BASE_FORMAT
 
     copy_src_tree()
+    # using namespace esphome must precede all variable declarations since
+    # codegen types assume this namespace is in scope (esphome_ns = global_ns).
     global_s = '#include "esphome.h"\n'
+    global_s += "using namespace esphome;\n"
     global_s += CORE.cpp_global_section
 
     full_file = f"{code_format[0] + CPP_INCLUDE_BEGIN}\n{global_s}{CPP_INCLUDE_END}"