No side effect with invalid inputs to save_obj / save_ply

Summary: Do not create output files with invalid inputs to `save_{obj,ply}()`.

Reviewed By: bottler

Differential Revision: D20720282

fbshipit-source-id: 3b611a10da6f6eecacab2a1900bf16f89e2000aa

pytorch3d/io/obj_io.py

@@ -526,6 +526,14 @@ def save_obj(f, verts, faces, decimal_places: Optional[int] = None):
         faces: LongTensor of shape (F, 3) giving faces.
         decimal_places: Number of decimal places for saving.
     """
+    if len(verts) and not (verts.dim() == 2 and verts.size(1) == 3):
+        message = "Argument 'verts' should either be empty or of shape (num_verts, 3)."
+        raise ValueError(message)
+
+    if len(faces) and not (faces.dim() == 2 and faces.size(1) == 3):
+        message = "Argument 'faces' should either be empty or of shape (num_faces, 3)."
+        raise ValueError(message)
+
     new_f = False
     if isinstance(f, str):
         new_f = True
@@ -541,21 +549,14 @@ def save_obj(f, verts, faces, decimal_places: Optional[int] = None):
 
 
 # TODO (nikhilar) Speed up this function.
-def _save(f, verts, faces, decimal_places: Optional[int] = None):
+def _save(f, verts, faces, decimal_places: Optional[int] = None) -> None:
+    assert not len(verts) or (verts.dim() == 2 and verts.size(1) == 3)
+    assert not len(faces) or (faces.dim() == 2 and faces.size(1) == 3)
+
     if not (len(verts) or len(faces)):
         warnings.warn("Empty 'verts' and 'faces' arguments provided")
         return
 
-    if len(verts) and not (verts.dim() == 2 and verts.size(1) == 3):
-        raise ValueError(
-            "Argument 'verts' should either be empty or of shape (num_verts, 3)."
-        )
-
-    if len(faces) and not (faces.dim() == 2 and faces.size(1) == 3):
-        raise ValueError(
-            "Argument 'faces' should either be empty or of shape (num_faces, 3)."
-        )
-
     verts, faces = verts.cpu(), faces.cpu()
 
     lines = ""

pytorch3d/io/ply_io.py

@@ -700,7 +700,7 @@ def load_ply(f):
     return verts, faces
 
 
-def _save_ply(f, verts, faces, decimal_places: Optional[int]):
+def _save_ply(f, verts, faces, decimal_places: Optional[int]) -> None:
     """
     Internal implementation for saving a mesh to a .ply file.
 
@@ -710,15 +710,8 @@ def _save_ply(f, verts, faces, decimal_places: Optional[int]):
         faces: LongTensor of shape (F, 3) giving faces.
         decimal_places: Number of decimal places for saving.
     """
-    if len(verts) and not (verts.dim() == 2 and verts.size(1) == 3):
-        raise ValueError(
-            "Argument 'verts' should either be empty or of shape (num_verts, 3)."
-        )
-
-    if len(faces) and not (faces.dim() == 2 and faces.size(1) == 3):
-        raise ValueError(
-            "Argument 'faces' should either be empty or of shape (num_faces, 3)."
-        )
+    assert not len(verts) or (verts.dim() == 2 and verts.size(1) == 3)
+    assert not len(faces) or (faces.dim() == 2 and faces.size(1) == 3)
 
     print("ply\nformat ascii 1.0", file=f)
     print(f"element vertex {verts.shape[0]}", file=f)
@@ -760,6 +753,14 @@ def save_ply(f, verts, faces, decimal_places: Optional[int] = None):
         faces: LongTensor of shape (F, 3) giving faces.
         decimal_places: Number of decimal places for saving.
     """
+    if len(verts) and not (verts.dim() == 2 and verts.size(1) == 3):
+        message = "Argument 'verts' should either be empty or of shape (num_verts, 3)."
+        raise ValueError(message)
+
+    if len(faces) and not (faces.dim() == 2 and faces.size(1) == 3):
+        message = "Argument 'faces' should either be empty or of shape (num_faces, 3)."
+        raise ValueError(message)
+
     new_f = False
     if isinstance(f, str):
         new_f = True