rf: Warn on all failed attempts to configure use_datalad

Author: effigies

templateflow/cli.py

@@ -31,6 +31,7 @@
 from acres import Loader as _Loader
 from click.decorators import FC, Option, _param_memo
 
+from templateflow.conf import _cache
 from templateflow.client import TemplateFlowClient
 
 load_data = _Loader(__spec__.parent)
@@ -48,7 +49,7 @@
 }
 ENTITY_EXCLUDE = {'template', 'description'}
 
-CLIENT = TemplateFlowClient()
+CLIENT = TemplateFlowClient(cache=_cache)
 CACHE = CLIENT.cache
 CONFIG = CACHE.config
 CACHE.ensure()

templateflow/conf/__init__.py

@@ -33,10 +33,6 @@ def __getattr__(name: str):
     raise AttributeError(f"module '{__name__}' has no attribute '{name}'")
 
 
-if _env_to_bool('TEMPLATEFLOW_USE_DATALAD', False) and not _cache.config.use_datalad:
-    warn('DataLad is not installed ➔ disabled.', stacklevel=2)
-
-
 if not _cache.precached:
     warn(
         f"""\

templateflow/conf/cache.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from dataclasses import dataclass, field
-from functools import cached_property
+from functools import cache, cached_property
 from pathlib import Path
 from warnings import warn
 
@@ -12,6 +12,19 @@
     from bids.layout import BIDSLayout
 
 
+# The first CacheConfig is initialized during import, so we need a higher
+# level of indirection for warnings to point to the user code.
+# After that, we will set the stack level to point to the CacheConfig() caller.
+STACKLEVEL = 6
+
+
+@cache
+def _have_datalad():
+    import importlib.util
+
+    return importlib.util.find_spec('datalad') is not None
+
+
 @dataclass
 class CacheConfig:
     root: Path = field(default_factory=get_templateflow_home)
@@ -22,10 +35,11 @@ class CacheConfig:
     timeout: int = field(default=10)
 
     def __post_init__(self):
-        if self.use_datalad:
-            from importlib.util import find_spec
-
-            self.use_datalad = find_spec('datalad') is not None
+        global STACKLEVEL
+        if self.use_datalad and not _have_datalad():
+            self.use_datalad = False
+            warn('DataLad is not installed ➔ disabled.', stacklevel=STACKLEVEL)
+        STACKLEVEL = 3
 
 
 @dataclass