Cyclic imports (#492)

.pylintrc

@@ -452,7 +452,6 @@ disable=raw-checker-failed,
         ## incompatible with black
         wrong-import-position,
         ## these need to be fixed at some point. here to make the build pass
-        cyclic-import,import-outside-toplevel,
         fixme,
 
 # Enable the message, report, category or checker with the given id(s). You can

urbanstats/data/circle.py

@@ -16,6 +16,8 @@
 
 from urbanstats.data.gpw import load_full_ghs
 from urbanstats.data.population_overlays import direct_population_overlay, relevant_regions
+from urbanstats.geometry.shapefiles.shapefile import Shapefile
+from urbanstats.geometry.shapefiles.shapefiles.urban_centers import URBAN_CENTERS
 
 
 class MapDataset:
@@ -429,8 +431,6 @@ def to_basic_geopandas_frame(map_shape, circles):
 
 
 def attach_urban_centers_to_frame(frame):
-    from urbanstats.geometry.shapefiles.shapefiles.urban_centers import URBAN_CENTERS
-
     urban_center_shapefile = URBAN_CENTERS.load_file()
     urban_center_shapefile.index = urban_center_shapefile.longname
     overlays = direct_population_overlay(frame, urban_center_shapefile)
@@ -756,7 +756,6 @@ def produce_image(population):
 
 
 def circle_shapefile_object(country_shapefile, population, just_usa):
-    from urbanstats.geometry.shapefiles.shapefile import Shapefile
 
     name = named_populations[population] + " Person Circle"
     if just_usa:

urbanstats/geometry/shapefiles/shapefile.py

@@ -4,8 +4,6 @@
 import geopandas as gpd
 import pandas as pd
 
-from urbanstats.special_cases.deduplicate_longnames import drop_duplicate
-
 
 @attr.s
 class Shapefile:
@@ -22,6 +20,18 @@ class Shapefile:
     tolerate_no_state = attr.ib(default=False)
 
     def load_file(self):
+        """
+        Load the shapefile and apply the filters and extractors.
+
+        This has a circular dependency with the deduplicate_longnames module, which
+        needs to load other shapefiles to figure out how to disambiguate duplicated
+        longnames.
+
+        This should be the only circular dependency related to shapefiles.
+        """
+        # pylint: disable=import-outside-toplevel,cyclic-import
+        from urbanstats.special_cases.deduplicate_longnames import drop_duplicate
+
         if isinstance(self.path, list):
             s = gpd.GeoDataFrame(pd.concat([gpd.read_file(p) for p in self.path]))
             s = s.reset_index(drop=True)

urbanstats/special_cases/deduplicate_longnames.py

@@ -5,6 +5,7 @@
 from permacache import permacache, stable_hash
 
 from urbanstats.data.circle import naive_directions_for_rows_with_names
+from urbanstats.geometry.shapefiles.shapefiles_list import shapefiles
 
 
 def strip_suffix(name):
@@ -101,14 +102,10 @@ def drop_duplicate(s, duplicates, drop_dup_shapefile_key):
 
 @lru_cache(None)
 def load_shapefile_cached(drop_dup_shapefile_key):
-    from urbanstats.geometry.shapefiles.shapefiles_list import shapefiles
-
     return shapefiles[drop_dup_shapefile_key].load_file()
 
 
 def shapefile_hash_key(sf_key):
-    from urbanstats.geometry.shapefiles.shapefiles_list import shapefiles
-
     return shapefiles[sf_key].hash_key