gclient_utils: Add temporary_file method.

Useful when passing information to a subcommand via a temporary file.

Bug: 1051631
Change-Id: I0b8deda921effd24a37109544e1e7ca22e00ba4e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2068942Reviewed-by: Josip Sokcevic <sokcevic@google.com>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>

gclient_utils.py

@@ -170,8 +170,8 @@ def FileRead(filename, mode='rbU'):
     return s
 
 
-def FileWrite(filename, content, mode='w'):
-  with codecs.open(filename, mode=mode, encoding='utf-8') as f:
+def FileWrite(filename, content, mode='w', encoding='utf-8'):
+  with codecs.open(filename, mode=mode, encoding=encoding) as f:
     f.write(content)
 
 
@@ -185,6 +185,35 @@ def temporary_directory(**kwargs):
       rmtree(tdir)
 
 
+@contextlib.contextmanager
+def temporary_file():
+  """Creates a temporary file.
+
+  On Windows, a file must be closed before it can be opened again. This function
+  allows to write something like:
+
+    with gclient_utils.temporary_file() as tmp:
+      gclient_utils.FileWrite(tmp, foo)
+      useful_stuff(tmp)
+
+  Instead of something like:
+
+    with tempfile.NamedTemporaryFile(delete=False) as tmp:
+      tmp.write(foo)
+      tmp.close()
+      try:
+        useful_stuff(tmp)
+      finally:
+        os.remove(tmp.name)
+  """
+  handle, name = tempfile.mkstemp()
+  os.close(handle)
+  try:
+    yield name
+  finally:
+    os.remove(name)
+
+
 def safe_rename(old, new):
   """Renames a file reliably.
 

git_cl.py

@@ -2342,12 +2342,10 @@ class Changelist(object):
       parent = self._ComputeParent(remote, upstream_branch, custom_cl_base,
                                    options.force, change_desc)
       tree = RunGit(['rev-parse', 'HEAD:']).strip()
-      with tempfile.NamedTemporaryFile(delete=False) as desc_tempfile:
-        desc_tempfile.write(change_desc.description.encode('utf-8', 'replace'))
-        desc_tempfile.close()
-        ref_to_push = RunGit(['commit-tree', tree, '-p', parent,
-                              '-F', desc_tempfile.name]).strip()
-        os.remove(desc_tempfile.name)
+      with gclient_utils.temporary_file() as desc_tempfile:
+        gclient_utils.FileWrite(desc_tempfile, change_desc.description)
+        ref_to_push = RunGit(
+            ['commit-tree', tree, '-p', parent, '-F', desc_tempfile]).strip()
     else:  # if not options.squash
       change_desc = ChangeDescription(
           options.message or _create_description_from_log(git_diff_args))

split_cl.py

@@ -15,6 +15,7 @@ import subprocess2
 import sys
 import tempfile
 
+import gclient_utils
 import git_footers
 import owners
 import owners_finder
@@ -119,13 +120,11 @@ def UploadCl(cl_index, num_cls, refactor_branch, refactor_branch_upstream,
   # Commit changes. The temporary file is created with delete=False so that it
   # can be deleted manually after git has read it rather than automatically
   # when it is closed.
-  with tempfile.NamedTemporaryFile(delete=False) as tmp_file:
-    tmp_file.write(
+  with gclient_utils.temporary_file() as tmp_file:
+    gclient_utils.FileWrite(
+        tmp_file,
         FormatDescriptionOrComment(description, directory, cl_index, num_cls))
-    # Close the file to let git open it at the next line.
-    tmp_file.close()
-    git.run('commit', '-F', tmp_file.name)
-    os.remove(tmp_file.name)
+    git.run('commit', '-F', tmp_file)
 
   # Upload a CL.
   upload_args = ['-f', '-r', reviewer]

tests/gclient_utils_test.py

@@ -337,24 +337,21 @@ class GClientUtilsTest(trial_dir.TestCase):
           expected, gclient_utils.ParseCodereviewSettingsContent(content))
 
   def testFileRead_Bytes(self):
-    with tempfile.NamedTemporaryFile(delete=False) as tmp:
-      tmp.write(b'foo \xe2\x9c bar')
-      # NamedTemporaryFiles must be closed on Windows before being opened again.
-      tmp.close()
-      try:
-        self.assertEqual('foo \ufffd bar', gclient_utils.FileRead(tmp.name))
-      finally:
-        os.remove(tmp.name)
+    with gclient_utils.temporary_file() as tmp:
+      gclient_utils.FileWrite(
+          tmp, b'foo \xe2\x9c bar', mode='wb', encoding=None)
+      self.assertEqual('foo \ufffd bar', gclient_utils.FileRead(tmp))
 
   def testFileRead_Unicode(self):
-    with tempfile.NamedTemporaryFile(delete=False) as tmp:
-      tmp.write(b'foo \xe2\x9c\x94 bar')
-      # NamedTemporaryFiles must be closed on Windows before being opened again.
-      tmp.close()
-      try:
-        self.assertEqual('foo ✔ bar', gclient_utils.FileRead(tmp.name))
-      finally:
-        os.remove(tmp.name)
+    with gclient_utils.temporary_file() as tmp:
+      gclient_utils.FileWrite(tmp, 'foo ✔ bar')
+      self.assertEqual('foo ✔ bar', gclient_utils.FileRead(tmp))
+
+  def testTemporaryFile(self):
+    with gclient_utils.temporary_file() as tmp:
+      gclient_utils.FileWrite(tmp, 'test')
+      self.assertEqual('test', gclient_utils.FileRead(tmp))
+    self.assertFalse(os.path.exists(tmp))
 
 
 if __name__ == '__main__':

tests/git_cl_test.py

@@ -32,7 +32,9 @@ import metrics
 # We have to disable monitoring before importing git_cl.
 metrics.DISABLE_METRICS_COLLECTION = True
 
+import contextlib
 import clang_format
+import gclient_utils
 import gerrit_util
 import git_cl
 import git_common
@@ -55,26 +57,14 @@ def _constantFn(return_value):
 CERR1 = callError(1)
 
 
-def MakeNamedTemporaryFileMock(test, expected_content):
-  class NamedTemporaryFileMock(object):
-    def __init__(self, *args, **kwargs):
-      self.name = '/tmp/named'
-      self.expected_content = expected_content.encode('utf-8', 'replace')
-
-    def __enter__(self):
-      return self
-
-    def __exit__(self, _type, _value, _tb):
-      pass
-
-    def write(self, content):
-      if self.expected_content:
-        test.assertEqual(self.expected_content, content)
-
-    def close(self):
-      pass
+class TemporaryFileMock(object):
+  def __init__(self):
+    self.suffix = 0
 
-  return NamedTemporaryFileMock
+  @contextlib.contextmanager
+  def __call__(self):
+    self.suffix += 1
+    yield '/tmp/fake-temp' + str(self.suffix)
 
 
 class ChangelistMock(object):
@@ -897,8 +887,9 @@ class TestGitCl(unittest.TestCase):
       calls += [
         ((['git', 'rev-parse', 'HEAD:'],),  # `HEAD:` means HEAD's tree hash.
          '0123456789abcdef'),
+        ((['FileWrite', '/tmp/fake-temp1', description],), None),
         ((['git', 'commit-tree', '0123456789abcdef', '-p', parent,
-           '-F', '/tmp/named'],),
+           '-F', '/tmp/fake-temp1'],),
          ref_to_push),
       ]
     else:
@@ -1178,9 +1169,7 @@ class TestGitCl(unittest.TestCase):
         change_id=change_id)
     if fetched_status != 'ABANDONED':
       mock.patch(
-          'tempfile.NamedTemporaryFile',
-          MakeNamedTemporaryFileMock(
-              self, expected_content=description)).start()
+          'gclient_utils.temporary_file', TemporaryFileMock()).start()
       mock.patch('os.remove', return_value=True).start()
       self.calls += self._gerrit_upload_calls(
           description, reviewers, squash,

tests/git_footers_test.py

@@ -17,6 +17,7 @@ else:
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
+import gclient_utils
 import git_footers
 
 class GitFootersTest(unittest.TestCase):
@@ -256,15 +257,10 @@ My commit message is my best friend. It is my life. I must master it.
       'sys.stdin',
       StringIO('line\r\nany spaces\r\n\r\n\r\nFoo: 1\nBar: 2\nFoo: 3'))
   def testToJson(self):
-    with tempfile.NamedTemporaryFile(delete=False) as tmp:
-      try:
-        # NamedTemporaryFiles must be closed on Windows before being opened
-        # again.
-        tmp.close()
-        self.assertEqual(git_footers.main(['--json', tmp.name]), 0)
-        js = json.load(open(tmp.name))
-      finally:
-        os.remove(tmp.name)
+    with gclient_utils.temporary_file() as tmp:
+      self.assertEqual(git_footers.main(['--json', tmp]), 0)
+      with open(tmp) as f:
+        js = json.load(f)
     self.assertEqual(js, {'Foo': ['3', '1'], 'Bar': ['2']})
 
 

tests/git_hyper_blame_test.py

@@ -28,6 +28,7 @@ sys.path.insert(0, DEPOT_TOOLS_ROOT)
 from testing_support import coverage_utils
 from testing_support import git_test_utils
 
+import gclient_utils
 import git_common
 
 GitRepo = git_test_utils.GitRepo
@@ -186,16 +187,16 @@ class GitHyperBlameMainTest(GitHyperBlameTestBase):
                        self.blame_line('A', '2*) line 2.1')]
     outbuf = BytesIO()
 
-    with tempfile.NamedTemporaryFile(mode='w+', prefix='ignore') as ignore_file:
-      ignore_file.write('# Line comments are allowed.\n')
-      ignore_file.write('\n')
-      ignore_file.write('{}\n'.format(self.repo['B']))
-      # A revision that is not in the repo (should be ignored).
-      ignore_file.write('xxxx\n')
-      ignore_file.flush()
+    with gclient_utils.temporary_file() as ignore_file:
+      gclient_utils.FileWrite(
+          ignore_file,
+          '# Line comments are allowed.\n'
+          '\n'
+          '{}\n'
+          'xxxx\n'.format(self.repo['B']))
       retval = self.repo.run(
           self.git_hyper_blame.main,
-          ['--ignore-file', ignore_file.name, 'tag_C', 'some/files/file'],
+          ['--ignore-file', ignore_file, 'tag_C', 'some/files/file'],
           outbuf)
 
     self.assertEqual(0, retval)