[addresses] Topological sort of address component dependencies so they get checked/removed in order

scripts/geodata/addresses/components.py

@@ -22,6 +22,7 @@ from geodata.boundaries.names import boundary_names
 from geodata.configs.utils import nested_get
 from geodata.coordinates.conversion import latlon_to_decimal
 from geodata.countries.names import *
+from geodata.graph.topsort import topsort
 from geodata.language_id.disambiguation import *
 from geodata.language_id.sample import sample_random_language
 from geodata.math.floats import isclose
@@ -155,6 +156,10 @@ class AddressComponents(object):
 
         all_values = self.component_bitset(forward_deps)
 
+        graph = {k: c['dependencies'] for k, c in six.iteritems(forward_deps)}
+        graph.update({c: [] for c in AddressFormatter.address_formatter_fields if c not in graph})
+        self.component_dependency_order = [c for c in topsort(graph) if graph[c]]
+
         for component, conf in six.iteritems(forward_deps):
             deps = conf['dependencies']
             self.component_dependencies[component] = self.component_bitset(deps) if deps else all_values
@@ -990,7 +995,10 @@ class AddressComponents(object):
         if not address_components:
             return
         component_bitset = self.component_bitset(address_components)
-        for c in list(address_components):
+
+        for c in self.component_dependency_order:
+            if c not in address_components:
+                continue
             if c in self.component_dependencies and not component_bitset & self.component_dependencies[c]:
                 address_components.pop(c)
                 component_bitset ^= self.component_bit_values[c]

scripts/geodata/graph/topsort.py

@@ -0,0 +1,32 @@
+
+def topsort(graph):
+    '''
+    Topological sort for a dependency graph, e.g.
+
+    Usage:
+
+    >>> graph = {
+            'a': ['b'],
+            'b': ['d'],
+            'c': ['d', 'a'],
+            'd': [],
+        }
+    >>> topsort(graph)
+
+    Returns: ['d', 'b', 'a', 'c']
+
+    '''
+    todos = set(graph.keys())
+    seen = set()
+    result = []
+    while todos:
+        for key in todos:
+            deps = graph[key]
+            if len([d for d in deps if d in seen]) == len(deps):
+                break
+        else:
+            raise Exception('Cycle: {}'.format(todos))
+        todos.remove(key)
+        result.append(key)
+        seen.add(key)
+    return result