diff --git a/pkgs/fetchPipMetadata/src/fetch_pip_metadata/lock_file_from_report.py b/pkgs/fetchPipMetadata/src/fetch_pip_metadata/lock_file_from_report.py
index 06cd0fd4..63184331 100644
--- a/pkgs/fetchPipMetadata/src/fetch_pip_metadata/lock_file_from_report.py
+++ b/pkgs/fetchPipMetadata/src/fetch_pip_metadata/lock_file_from_report.py
@@ -143,14 +143,6 @@ def evaluate_requirements(env, reqs, dependencies, root_name, extras, seen):
     requirements to save space in the file.
     A circuit breaker is included to avoid infinite recursion in nix.
     """
-    if root_name in seen:
-        print(
-            f"fatal: cycle detected: {root_name} ({' '.join(seen)})",
-            file=sys.stderr,  # noqa: E501
-        )
-        sys.exit(1)
-    # we copy "seen", because we want to track cycles per
-    # tree-branch and the original would be visible for all branches.
     seen = seen.copy()
     seen.append(root_name)
 
@@ -160,10 +152,11 @@ def evaluate_requirements(env, reqs, dependencies, root_name, extras, seen):
     for req in reqs[root_name]:
         if (not req.marker) or evaluate_extras(req, extras, env):
             req_name = canonicalize_name(req.name)
-            dependencies[root_name].add(req_name)
-            evaluate_requirements(
-                env, reqs, dependencies, req_name, req.extras, seen
-            )  # noqa: 501
+            if req_name not in seen:
+                dependencies[root_name].add(req_name)
+                evaluate_requirements(
+                    env, reqs, dependencies, req_name, req.extras, seen
+                )  # noqa: 501
     return dependencies
 
 
diff --git a/pkgs/fetchPipMetadata/src/tests/test_evaluate_requirements.py b/pkgs/fetchPipMetadata/src/tests/test_evaluate_requirements.py
index decd5a62..59e9ef80 100644
--- a/pkgs/fetchPipMetadata/src/tests/test_evaluate_requirements.py
+++ b/pkgs/fetchPipMetadata/src/tests/test_evaluate_requirements.py
@@ -68,3 +68,23 @@ def test_platform_mismatch():
         seen=[],
     )
     assert result == dict(root_package=set())
+
+
+def test_cycle():
+    result = l.evaluate_requirements(
+        env={},
+        reqs=dict(
+            root_package={Requirement("foo")},
+            foo={Requirement("bar")},
+            bar={Requirement("foo")},
+        ),
+        dependencies=dict(),
+        root_name="root_package",
+        extras=None,
+        seen=[],
+    )
+    assert result == dict(
+        root_package={"foo"},
+        foo={"bar"},
+        bar=set(),
+    )