fix: robuster module import

Author: oesteban

templateflow/conf/__init__.py

@@ -1,4 +1,5 @@
 """Configuration and settings."""
+
 import re
 from contextlib import suppress
 from functools import wraps
@@ -43,9 +44,19 @@ def _env_to_bool(envvar: str, default: bool) -> bool:
 TF_CACHED = True
 TF_GET_TIMEOUT = 10
 
+if TF_USE_DATALAD:
+    try:
+        from datalad.api import install
+    except ImportError:
+        warn('DataLad is not installed ➔ disabled.')
+        TF_USE_DATALAD = False
+
+if not TF_USE_DATALAD:
+    from templateflow.conf._s3 import update as _update_s3
+
 
 def _init_cache():
-    global TF_HOME, TF_CACHED, TF_USE_DATALAD
+    global TF_CACHED
 
     if not TF_HOME.exists() or not list(TF_HOME.iterdir()):
         TF_CACHED = False
@@ -58,17 +69,9 @@ def _init_cache():
             stacklevel=2,
         )
         if TF_USE_DATALAD:
-            try:
-                from datalad.api import install
-            except ImportError:
-                TF_USE_DATALAD = False
-            else:
-                TF_HOME.parent.mkdir(exist_ok=True, parents=True)
-                install(path=str(TF_HOME), source=TF_GITHUB_SOURCE, recursive=True)
-
-        if not TF_USE_DATALAD:
-            from ._s3 import update as _update_s3
-
+            TF_HOME.parent.mkdir(exist_ok=True, parents=True)
+            install(path=str(TF_HOME), source=TF_GITHUB_SOURCE, recursive=True)
+        else:
             _update_s3(TF_HOME, local=True, overwrite=TF_AUTOUPDATE, silent=True)
 
 
@@ -85,18 +88,16 @@ def wrapper(*args, **kwargs):
         if TF_LAYOUT is None:
             from bids import __version__
 
-            raise RuntimeError(
-                f'A layout with PyBIDS <{__version__}> could not be initiated'
-            )
+            raise RuntimeError(f'A layout with PyBIDS <{__version__}> could not be initiated')
         return func(*args, **kwargs)
 
     return wrapper
 
 
 def update(local=False, overwrite=True, silent=False):
     """Update an existing DataLad or S3 home."""
-    if TF_USE_DATALAD and _update_datalad():
-        success = True
+    if TF_USE_DATALAD:
+        success = _update_datalad()
     else:
         from ._s3 import update as _update_s3
 
@@ -116,7 +117,6 @@ def update(local=False, overwrite=True, silent=False):
 
 def wipe():
     """Clear the cache if functioning in S3 mode."""
-    global TF_USE_DATALAD, TF_HOME
 
     if TF_USE_DATALAD:
         print('TemplateFlow is configured in DataLad mode, wipe() has no effect')
@@ -131,9 +131,7 @@ def _onerror(func, path, excinfo):
         from pathlib import Path
 
         if Path(path).exists():
-            print(
-                f'Warning: could not delete <{path}>, please clear the cache manually.'
-            )
+            print(f'Warning: could not delete <{path}>, please clear the cache manually.')
 
     rmtree(TF_HOME, onerror=_onerror)
     _init_cache()
@@ -191,12 +189,6 @@ def init_layout():
         ),
     )
 
-def _preload():
-    global TF_HOME, TF_USE_DATALAD, TF_AUTOUPDATE
-    TF_HOME = Path(getenv('TEMPLATEFLOW_HOME', str(TF_DEFAULT_HOME))).absolute()
-    TF_USE_DATALAD = _env_to_bool('TEMPLATEFLOW_USE_DATALAD', False)
-    TF_AUTOUPDATE = _env_to_bool('TEMPLATEFLOW_AUTOUPDATE', True)
-
 
 with suppress(ImportError):
     init_layout()

templateflow/tests/test_conf.py

@@ -21,13 +21,12 @@
 #     https://www.nipreps.org/community/licensing/
 #
 """Tests the config module."""
-from pathlib import Path
+
 from importlib import reload
 from shutil import rmtree
 
 import pytest
 
-from templateflow import api
 from templateflow import conf as tfc
 
 
@@ -40,6 +39,7 @@ def _find_message(lines, msg, reverse=True):
             return True
     return False
 
+
 @pytest.mark.parametrize('use_datalad', ['off', 'on'])
 def test_conf_init(monkeypatch, tmp_path, use_datalad):
     """Check the correct functioning of config set-up."""
@@ -61,7 +61,9 @@ def test_conf_init(monkeypatch, tmp_path, use_datalad):
 def test_setup_home(monkeypatch, tmp_path, capsys, use_datalad):
     """Check the correct functioning of the installation hook."""
 
-    use_pre = tfc._env_to_bool('TEMPLATEFLOW_USE_DATALAD', False)
+    if use_datalad == 'on':
+        # ImportError if not installed
+        pass
 
     home = (tmp_path / f'setup-home-{use_datalad}').absolute()
     monkeypatch.setenv('TEMPLATEFLOW_USE_DATALAD', use_datalad)
@@ -70,7 +72,6 @@ def test_setup_home(monkeypatch, tmp_path, capsys, use_datalad):
     use_post = tfc._env_to_bool('TEMPLATEFLOW_USE_DATALAD', False)
     assert use_post is (use_datalad == 'on')
 
-    tfc._preload()
     with capsys.disabled():
         reload(tfc)