Fix deadlock in holidays dynamic loading (#115385)

homeassistant/components/holiday/__init__.py

@@ -2,15 +2,36 @@
 
 from __future__ import annotations
 
+from functools import partial
+
+from holidays import country_holidays
+
 from homeassistant.config_entries import ConfigEntry
-from homeassistant.const import Platform
+from homeassistant.const import CONF_COUNTRY, Platform
 from homeassistant.core import HomeAssistant
+from homeassistant.setup import SetupPhases, async_pause_setup
+
+from .const import CONF_PROVINCE
 
 PLATFORMS: list[Platform] = [Platform.CALENDAR]
 
 
 async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     """Set up Holiday from a config entry."""
+    country: str = entry.data[CONF_COUNTRY]
+    province: str | None = entry.data.get(CONF_PROVINCE)
+
+    # We only import here to ensure that that its not imported later
+    # in the event loop since the platforms will call country_holidays
+    # which loads python code from disk.
+    with async_pause_setup(hass, SetupPhases.WAIT_IMPORT_PACKAGES):
+        # import executor job is used here because multiple integrations use
+        # the holidays library and it is not thread safe to import it in parallel
+        # https://github.com/python/cpython/issues/83065
+        await hass.async_add_import_executor_job(
+            partial(country_holidays, country, subdiv=province)
+        )
+
     await hass.config_entries.async_forward_entry_setups(entry, PLATFORMS)
 
     return True

homeassistant/components/workday/__init__.py

@@ -11,6 +11,7 @@ from homeassistant.const import CONF_COUNTRY, CONF_LANGUAGE
 from homeassistant.core import HomeAssistant
 from homeassistant.exceptions import ConfigEntryError
 from homeassistant.helpers.issue_registry import IssueSeverity, async_create_issue
+from homeassistant.setup import SetupPhases, async_pause_setup
 
 from .const import CONF_PROVINCE, DOMAIN, PLATFORMS
 
@@ -23,7 +24,11 @@ async def _async_validate_country_and_province(
     if not country:
         return
     try:
-        await hass.async_add_executor_job(country_holidays, country)
+        with async_pause_setup(hass, SetupPhases.WAIT_IMPORT_PACKAGES):
+            # import executor job is used here because multiple integrations use
+            # the holidays library and it is not thread safe to import it in parallel
+            # https://github.com/python/cpython/issues/83065
+            await hass.async_add_import_executor_job(country_holidays, country)
     except NotImplementedError as ex:
         async_create_issue(
             hass,
@@ -41,9 +46,13 @@ async def _async_validate_country_and_province(
     if not province:
         return
     try:
-        await hass.async_add_executor_job(
-            partial(country_holidays, country, subdiv=province)
-        )
+        with async_pause_setup(hass, SetupPhases.WAIT_IMPORT_PACKAGES):
+            # import executor job is used here because multiple integrations use
+            # the holidays library and it is not thread safe to import it in parallel
+            # https://github.com/python/cpython/issues/83065
+            await hass.async_add_import_executor_job(
+                partial(country_holidays, country, subdiv=province)
+            )
     except NotImplementedError as ex:
         async_create_issue(
             hass,
@@ -73,9 +82,13 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     await _async_validate_country_and_province(hass, entry, country, province)
 
     if country and CONF_LANGUAGE not in entry.options:
-        cls: HolidayBase = await hass.async_add_executor_job(
-            partial(country_holidays, country, subdiv=province)
-        )
+        with async_pause_setup(hass, SetupPhases.WAIT_IMPORT_PACKAGES):
+            # import executor job is used here because multiple integrations use
+            # the holidays library and it is not thread safe to import it in parallel
+            # https://github.com/python/cpython/issues/83065
+            cls: HolidayBase = await hass.async_add_import_executor_job(
+                partial(country_holidays, country, subdiv=province)
+            )
         default_language = cls.default_language
         new_options = entry.options.copy()
         new_options[CONF_LANGUAGE] = default_language