From 2d941e011be552fcb1bda222227b5bbd0b91a308 Mon Sep 17 00:00:00 2001
From: Etienne Pot <epot@google.com>
Date: Wed, 16 Dec 2020 06:31:02 -0800
Subject: [PATCH] Fix `path.touch()` when file already exists

PiperOrigin-RevId: 347811114
---
 tensorflow_datasets/core/utils/gpath_test.py | 24 +++++++++++++++++++-
 tensorflow_datasets/core/utils/type_utils.py |  7 ++++--
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/tensorflow_datasets/core/utils/gpath_test.py b/tensorflow_datasets/core/utils/gpath_test.py
index 6609cd7c4f6..980fcfd1ffb 100644
--- a/tensorflow_datasets/core/utils/gpath_test.py
+++ b/tensorflow_datasets/core/utils/gpath_test.py
@@ -211,7 +211,29 @@ def test_open(gcs_mocked_path: pathlib.Path):
   assert len(list(gcs_mocked_path.joinpath('bucket/dataset').iterdir())) == 6
 
 
-def test_read_write(gcs_mocked_path: pathlib.Path):  # pylint: disable=unused-argument
+@pytest.mark.usefixtures('gcs_mocked_path')
+def test_touch():
+  root_path = gpathlib.PosixGPath('gs://bucket/')
+  root_path.mkdir(parents=True)
+  assert root_path.exists()
+
+  # File don't exists, touch create it
+  file_path = root_path / 'test.txt'
+  assert not file_path.exists()
+  file_path.touch()
+  assert file_path.exists()
+  assert file_path.read_text() == ''  # File content is empty  # pylint: disable=g-explicit-bool-comparison
+
+  file_path.write_text('Some content')
+  file_path.touch()  # Should be a no-op
+  assert file_path.read_text() == 'Some content'  # Content still exists
+
+  with pytest.raises(FileExistsError):
+    file_path.touch(exist_ok=False)
+
+
+@pytest.mark.usefixtures('gcs_mocked_path')
+def test_read_write():
 
   gpath = gpathlib.PosixGPath('gs://file.txt')
 
diff --git a/tensorflow_datasets/core/utils/type_utils.py b/tensorflow_datasets/core/utils/type_utils.py
index 03cca2b476e..087ff4e900e 100644
--- a/tensorflow_datasets/core/utils/type_utils.py
+++ b/tensorflow_datasets/core/utils/type_utils.py
@@ -213,8 +213,11 @@ def write_text(
   def touch(self, mode: int = 0o666, exist_ok: bool = True) -> None:
     """Create a file at this given path."""
     del mode  # Unused
-    if self.exists() and not exist_ok:
-      raise FileExistsError(f'{self} already exists.')
+    if self.exists():
+      if exist_ok:
+        return
+      else:
+        raise FileExistsError(f'{self} already exists.')
     self.write_text('')
 
   @abc.abstractmethod