Track dependency categories on recursive dependencies

colcon_core/package_descriptor.py

@@ -71,16 +71,26 @@ def get_dependencies(self, *, categories=None):
         :raises AssertionError: if the package name is listed as a dependency
         """
         dependencies = set()
+        categories_by_dependency = defaultdict(list)
         if categories is None:
             categories = self.dependencies.keys()
         for category in sorted(categories):
-            dependencies |= self.dependencies[category]
+            for dependency in self.dependencies[category]:
+                categories_by_dependency[dependency].append(category)
+        for dependency, categories in categories_by_dependency.items():
+            if isinstance(dependency, DependencyDescriptor):
+                # duplicate the descriptor and metadata
+                dependency = deepcopy(dependency)
+            else:
+                dependency = DependencyDescriptor(dependency)
+            # note that the category list is not merged when a dependency
+            # appears multiple times in a package's tree, and the most shallow
+            # instance prevails.
+            dependency.metadata['categories'] = categories
+            dependencies.add(dependency)
         assert self.name not in dependencies, \
             f"The package '{self.name}' has a dependency with the same name"
-        return {
-            (DependencyDescriptor(d)
-                if not isinstance(d, DependencyDescriptor) else d)
-            for d in dependencies}
+        return dependencies
 
     def get_recursive_dependencies(
         self, descriptors, direct_categories=None, recursive_categories=None,
@@ -127,8 +137,7 @@ def get_recursive_dependencies(
                 for d in descs:
                     queue |= d.get_dependencies(
                         categories=recursive_categories)
-                # duplicate the descriptor and metadata and add the depth
-                dep = deepcopy(dep)
+                # add the depth
                 dep.metadata['depth'] = depth
                 # add dependency to result set
                 dependencies.add(dep)

test/test_package_descriptor.py

@@ -4,6 +4,7 @@
 import os
 from pathlib import Path
 
+from colcon_core.dependency_descriptor import DependencyDescriptor
 from colcon_core.package_descriptor import PackageDescriptor
 import pytest
 
@@ -57,9 +58,9 @@ def test_get_recursive_dependencies():
 
     d1 = PackageDescriptor('/other/path')
     d1.name = 'B'
-    d1.dependencies['build'].add('e')
-    d1.dependencies['run'].add('F')
-    d1.dependencies['test'].add('G')
+    d1.dependencies['build'].add(DependencyDescriptor('e'))
+    d1.dependencies['run'].add(DependencyDescriptor('F'))
+    d1.dependencies['test'].add(DependencyDescriptor('G'))
 
     d2 = PackageDescriptor('/another/path')
     d2.name = 'd'