fix: follow symlinks in list_files_recursively with cycle detection

list_files_recursively now uses followlinks=True so symlinked
directories under input/ and output/ roots are traversed, matching
the existing behavior of folder_paths.recursive_search for models.

Tracks (st_dev, st_ino) pairs of visited directories to detect and
break circular symlink loops safely.

Amp-Thread-ID: https://ampcode.com/threads/T-019c9220-21b8-7678-b428-9215ff1bb011
Co-authored-by: Amp <amp@ampcode.com>

app/assets/services/file_utils.py

@@ -42,14 +42,26 @@ def is_visible(name: str) -> bool:
 
 
 def list_files_recursively(base_dir: str) -> list[str]:
-    """Recursively list all files in a directory."""
+    """Recursively list all files in a directory, following symlinks."""
     out: list[str] = []
     base_abs = os.path.abspath(base_dir)
     if not os.path.isdir(base_abs):
         return out
+    # Track seen real directory identities to prevent circular symlink loops
+    seen_dirs: set[tuple[int, int]] = set()
     for dirpath, subdirs, filenames in os.walk(
-        base_abs, topdown=True, followlinks=False
+        base_abs, topdown=True, followlinks=True
     ):
+        try:
+            st = os.stat(dirpath)
+            dir_id = (st.st_dev, st.st_ino)
+        except OSError:
+            subdirs.clear()
+            continue
+        if dir_id in seen_dirs:
+            subdirs.clear()
+            continue
+        seen_dirs.add(dir_id)
         subdirs[:] = [d for d in subdirs if is_visible(d)]
         for name in filenames:
             if not is_visible(name):

tests-unit/assets_test/test_file_utils.py

@@ -1,3 +1,8 @@
+import os
+import sys
+
+import pytest
+
 from app.assets.services.file_utils import is_visible, list_files_recursively
 
 
@@ -53,3 +58,64 @@ class TestListFilesRecursively:
     def test_nonexistent_directory(self, tmp_path):
         result = list_files_recursively(str(tmp_path / "nonexistent"))
         assert result == []
+
+    @pytest.mark.skipif(sys.platform == "win32", reason="symlinks need privileges on Windows")
+    def test_follows_symlinked_directories(self, tmp_path):
+        target = tmp_path / "real_dir"
+        target.mkdir()
+        (target / "model.safetensors").write_text("data")
+
+        root = tmp_path / "root"
+        root.mkdir()
+        (root / "link").symlink_to(target)
+
+        result = list_files_recursively(str(root))
+
+        assert len(result) == 1
+        assert result[0].endswith("model.safetensors")
+        assert "link" in result[0]
+
+    @pytest.mark.skipif(sys.platform == "win32", reason="symlinks need privileges on Windows")
+    def test_follows_symlinked_files(self, tmp_path):
+        real_file = tmp_path / "real.txt"
+        real_file.write_text("content")
+
+        root = tmp_path / "root"
+        root.mkdir()
+        (root / "link.txt").symlink_to(real_file)
+
+        result = list_files_recursively(str(root))
+
+        assert len(result) == 1
+        assert result[0].endswith("link.txt")
+
+    @pytest.mark.skipif(sys.platform == "win32", reason="symlinks need privileges on Windows")
+    def test_circular_symlinks_do_not_loop(self, tmp_path):
+        dir_a = tmp_path / "a"
+        dir_a.mkdir()
+        (dir_a / "file.txt").write_text("a")
+        # a/b -> a  (circular)
+        (dir_a / "b").symlink_to(dir_a)
+
+        result = list_files_recursively(str(dir_a))
+
+        assert len(result) == 1
+        assert result[0].endswith("file.txt")
+
+    @pytest.mark.skipif(sys.platform == "win32", reason="symlinks need privileges on Windows")
+    def test_mutual_circular_symlinks(self, tmp_path):
+        dir_a = tmp_path / "a"
+        dir_b = tmp_path / "b"
+        dir_a.mkdir()
+        dir_b.mkdir()
+        (dir_a / "file_a.txt").write_text("a")
+        (dir_b / "file_b.txt").write_text("b")
+        # a/link_b -> b and b/link_a -> a
+        (dir_a / "link_b").symlink_to(dir_b)
+        (dir_b / "link_a").symlink_to(dir_a)
+
+        result = list_files_recursively(str(dir_a))
+        basenames = sorted(os.path.basename(p) for p in result)
+
+        assert "file_a.txt" in basenames
+        assert "file_b.txt" in basenames