reverse-dependences: Fix bug in find-package-dependents script

find-package-dependents was passing the user's max_results limit
to the generate_direct_dependents function. This would be fine,
except we sometimes need more than max_results generated if some
of the results are filtered by the user's filter command.

The upshot is the script would sometimes traverse the dependents
tree deep instead of wide, leading to performance issues.

This commit drops the max_result limit on generate_direct_dependents,
since it's wrong and not needed anyway (because max_results is
already handled elsewhere).

This commit also adds a couple of test cases to make sure the problem
doesn't creep in again.

Author: halfline

scripts/find-package-dependents.py

@@ -997,7 +997,7 @@ def build_dependents_graph(
         any_filtered_dependents = False
         for dependent in generate_direct_dependents(
                 package, repository_paths, metrics, dependency_cache, verbose,
-                cache_only=result_limit_hit, max_results=max_results
+                cache_only=result_limit_hit
         ):
             if show_source_packages:
                 dependent = query_source_package(

scripts/tests/test-find-package-dependents.py

@@ -1876,6 +1876,104 @@ def mock_dependents(package_name, *args, **kwargs):
                 self.assertIn("mutter", result["libwayland-server"]["dependents"])
                 self.assertNotIn("libwayland-server", result["mutter"]["dependents"])
 
+    @patch.object(find_package_dependents, 'run_command')
+    def test_breadth_first_with_max_results_and_filtering(self, mock_run_command):
+        """Test that breadth-first traversal works correctly with max_results even when some dependents are filtered out.
+
+        This test verifies the fix for the bug where max_results was incorrectly applied to generate_direct_dependents,
+        causing performance issues due to deep traversal when filters would reject some results.
+        """
+        def mock_dnf_calls(command_args):
+            full_command = ' '.join(command_args)
+            if "libwayland-server" in full_command:
+                return {"return_code": 0, "output": "mutter\nweston\nsway\nkwin"}
+            else:
+                return {"return_code": 0, "output": ""}
+
+        mock_run_command.side_effect = mock_dnf_calls
+
+        def mock_filter_command(package_name, filter_cmd, *args, **kwargs):
+            return package_name in ["mutter", "kwin"]
+
+        with patch.object(find_package_dependents, 'run_filter_command', side_effect=mock_filter_command):
+            result = find_package_dependents.build_dependents_graph(
+                root_package="libwayland-server",
+                repository_paths=self.repositories,
+                show_source_packages=False,
+                source_cache=self.source_cache,
+                metrics=self.metrics,
+                filter_cache=self.filter_cache,
+                dependency_cache=self.dependency_cache,
+                max_results=1,  # Very small limit to test breadth-first behavior
+                keep_cycles=False,
+                verbose=False,
+                filter_command="test filter",  # Enable filtering
+                allow_missing=False
+            )
+
+            self.assertIn("libwayland-server", result)
+            root_dependents = result["libwayland-server"]["dependents"]
+
+            self.assertGreaterEqual(len(root_dependents), 1)
+
+            valid_dependents = [dep for dep in root_dependents if dep in ["mutter", "kwin"]]
+            self.assertGreaterEqual(len(valid_dependents), 1)
+
+            self.assertNotIn("sway", root_dependents)
+            self.assertNotIn("weston", root_dependents)
+
+            self.assertTrue(result["libwayland-server"]["partial"])
+
+
+    @patch.object(find_package_dependents, 'run_command')
+    def test_breadth_first_multi_level_traversal(self, mock_run_command):
+        """Test breadth-first traversal works correctly across multiple dependency levels with filtering.
+        """
+        def mock_dnf_calls(command_args):
+            full_command = ' '.join(command_args)
+            if "glibc" in full_command:
+                return {"return_code": 0, "output": "systemd\nbash\npodman\nbuildah\nkernel"}
+            elif "podman" in full_command:
+                return {"return_code": 0, "output": "cockpit-podman\ntoolbox"}
+            elif "buildah" in full_command:
+                return {"return_code": 0, "output": "container-tools\nskopeo"}
+            else:
+                return {"return_code": 0, "output": ""}
+
+        mock_run_command.side_effect = mock_dnf_calls
+
+        def mock_filter_command(package_name, filter_cmd, *args, **kwargs):
+            return package_name in ["podman", "buildah", "cockpit-podman", "toolbox", "container-tools", "skopeo"]
+
+        with patch.object(find_package_dependents, 'run_filter_command', side_effect=mock_filter_command):
+            result = find_package_dependents.build_dependents_graph(
+                root_package="glibc",
+                repository_paths=self.repositories,
+                show_source_packages=False,
+                source_cache=self.source_cache,
+                metrics=self.metrics,
+                filter_cache=self.filter_cache,
+                dependency_cache=self.dependency_cache,
+                max_results=4,
+                keep_cycles=False,
+                verbose=False,
+                filter_command="test filter",
+                allow_missing=False
+            )
+
+            self.assertIn("glibc", result)
+            self.assertIn("podman", result)
+            self.assertIn("buildah", result)
+
+            podman_children = result["podman"]["dependents"]
+            self.assertIn("cockpit-podman", podman_children)
+            self.assertIn("toolbox", podman_children)
+
+            root_dependents = result["glibc"]["dependents"]
+            self.assertNotIn("systemd", root_dependents)
+            self.assertNotIn("bash", root_dependents)
+            self.assertNotIn("kernel", root_dependents)
+
 
 def print_header():
     print("─" * 70)