Add staged_files_only context manager.

pre_commit/prefixed_command_runner.py

@@ -6,6 +6,9 @@ import subprocess
 
 class CalledProcessError(RuntimeError):
     def __init__(self, returncode, cmd, expected_returncode, output=None):
+        super(CalledProcessError, self).__init__(
+            returncode, cmd, expected_returncode, output,
+        )
         self.returncode = returncode
         self.cmd = cmd
         self.expected_returncode = expected_returncode
@@ -15,13 +18,13 @@ class CalledProcessError(RuntimeError):
         return (
             'Command: {0!r}\n'
             'Return code: {1}\n'
-            'Expected return code {2}\n',
+            'Expected return code: {2}\n'
             'Output: {3!r}\n'.format(
                 self.cmd,
                 self.returncode,
                 self.expected_returncode,
                 self.output,
-            ),
+            )
         )
 
 
@@ -48,15 +51,15 @@ class PrefixedCommandRunner(object):
             self.__makedirs(self.prefix_dir)
 
     def run(self, cmd, retcode=0, stdin=None, **kwargs):
+        popen_kwargs = {
+            'stdin': subprocess.PIPE,
+            'stdout': subprocess.PIPE,
+            'stderr': subprocess.PIPE,
+        }
+        popen_kwargs.update(kwargs)
         self._create_path_if_not_exists()
         replaced_cmd = _replace_cmd(cmd, prefix=self.prefix_dir)
-        proc = self.__popen(
-            replaced_cmd,
-            stdin=subprocess.PIPE,
-            stdout=subprocess.PIPE,
-            stderr=subprocess.PIPE,
-            **kwargs
-        )
+        proc = self.__popen(replaced_cmd, **popen_kwargs)
         stdout, stderr = proc.communicate(stdin)
         returncode = proc.returncode
 

pre_commit/staged_files_only.py

@@ -0,0 +1,47 @@
+
+import contextlib
+import time
+
+from pre_commit.prefixed_command_runner import CalledProcessError
+
+
+@contextlib.contextmanager
+def staged_files_only(cmd_runner):
+    """Clear any unstaged changes from the git working directory inside this
+    context.
+
+    Args:
+        cmd_runner - PrefixedCommandRunner
+    """
+    # Determine if there are unstaged files
+    retcode, _, _ = cmd_runner.run(
+        ['git', 'diff-files', '--quiet'],
+        retcode=None,
+    )
+    if retcode:
+        # TODO: print a warning message that unstaged things are being stashed
+        # Save the current unstaged changes as a patch
+        # TODO: use a more unique patch filename
+        patch_filename = cmd_runner.path('patch{0}'.format(time.time()))
+        with open(patch_filename, 'w') as patch_file:
+            cmd_runner.run(['git', 'diff', '--binary'], stdout=patch_file)
+
+        # Clear the working directory of unstaged changes
+        cmd_runner.run(['git', 'checkout', '--', '.'])
+        try:
+            yield
+        finally:
+            # Try to apply the patch we saved
+            try:
+                cmd_runner.run(['git', 'apply', patch_filename])
+            except CalledProcessError:
+                # TOOD: print a warning about rolling back changes made by hooks
+                # We failed to apply the patch, presumably due to fixes made
+                # by hooks.
+                # Roll back the changes made by hooks.
+                cmd_runner.run(['git', 'checkout', '--', '.'])
+                cmd_runner.run(['git', 'apply', patch_filename])
+    else:
+        # There weren't any staged files so we don't need to do anything
+        # special
+        yield

tests/prefixed_command_runner_test.py

@@ -9,6 +9,16 @@ from pre_commit.prefixed_command_runner import CalledProcessError
 from pre_commit.prefixed_command_runner import PrefixedCommandRunner
 
 
+def test_CalledProcessError_str():
+    error = CalledProcessError(1, ['git', 'status'], 0, ('stdout', 'stderr'))
+    assert str(error) == (
+        "Command: ['git', 'status']\n"
+        "Return code: 1\n"
+        "Expected return code: 0\n"
+        "Output: ('stdout', 'stderr')\n"
+    )
+
+
 @pytest.fixture
 def popen_mock():
     popen = mock.Mock(spec=subprocess.Popen)

tests/staged_files_only_test.py

@@ -0,0 +1,218 @@
+
+import os.path
+import pytest
+import shutil
+from plumbum import local
+
+import pre_commit.constants as C
+from pre_commit.prefixed_command_runner import PrefixedCommandRunner
+from pre_commit.staged_files_only import staged_files_only
+from testing.auto_namedtuple import auto_namedtuple
+from testing.util import get_resource_path
+
+
+FOO_CONTENTS = '\n'.join(('1', '2', '3', '4', '5', '6', '7', '8', ''))
+
+
+def get_short_git_status():
+    git_status = local['git']['status', '-s']()
+    return dict(reversed(line.split()) for line in git_status.splitlines())
+
+
+@pytest.yield_fixture
+def foo_staged(empty_git_dir):
+    with open('.gitignore', 'w') as gitignore_file:
+        gitignore_file.write(C.HOOKS_WORKSPACE + '\n')
+    local['git']['add', '.']()
+    local['git']['commit', '-m', 'add gitignore']()
+
+    with open('foo', 'w') as foo_file:
+        foo_file.write(FOO_CONTENTS)
+    local['git']['add', 'foo']()
+    foo_filename = os.path.join(empty_git_dir, 'foo')
+    yield auto_namedtuple(path=empty_git_dir, foo_filename=foo_filename)
+
+
+@pytest.fixture
+def cmd_runner():
+    return PrefixedCommandRunner(C.HOOKS_WORKSPACE)
+
+
+def _test_foo_state(path, foo_contents=FOO_CONTENTS, status='A'):
+    assert os.path.exists(path.foo_filename)
+    assert open(path.foo_filename).read() == foo_contents
+    actual_status = get_short_git_status()['foo']
+    assert status == actual_status
+
+
+def test_foo_staged(foo_staged):
+    _test_foo_state(foo_staged)
+
+
+def test_foo_nothing_unstaged(foo_staged, cmd_runner):
+    with staged_files_only(cmd_runner):
+        _test_foo_state(foo_staged)
+    _test_foo_state(foo_staged)
+
+
+def test_foo_something_unstaged(foo_staged, cmd_runner):
+    with open(foo_staged.foo_filename, 'w') as foo_file:
+        foo_file.write('herp\nderp\n')
+
+    _test_foo_state(foo_staged, 'herp\nderp\n', 'AM')
+
+    with staged_files_only(cmd_runner):
+        _test_foo_state(foo_staged)
+
+    _test_foo_state(foo_staged, 'herp\nderp\n', 'AM')
+
+
+def test_foo_both_modify_non_conflicting(foo_staged, cmd_runner):
+    with open(foo_staged.foo_filename, 'w') as foo_file:
+        foo_file.write(FOO_CONTENTS + '9\n')
+
+    _test_foo_state(foo_staged, FOO_CONTENTS + '9\n', 'AM')
+
+    with staged_files_only(cmd_runner):
+        _test_foo_state(foo_staged)
+
+        # Modify the file as part of the "pre-commit"
+        with open(foo_staged.foo_filename, 'w') as foo_file:
+            foo_file.write(FOO_CONTENTS.replace('1', 'a'))
+
+        _test_foo_state(foo_staged, FOO_CONTENTS.replace('1', 'a'), 'AM')
+
+    _test_foo_state(foo_staged, FOO_CONTENTS.replace('1', 'a') + '9\n', 'AM')
+
+
+def test_foo_both_modify_conflicting(foo_staged, cmd_runner):
+    with open(foo_staged.foo_filename, 'w') as foo_file:
+        foo_file.write(FOO_CONTENTS.replace('1', 'a'))
+
+    _test_foo_state(foo_staged, FOO_CONTENTS.replace('1', 'a'), 'AM')
+
+    with staged_files_only(cmd_runner):
+        _test_foo_state(foo_staged)
+
+        # Modify in the same place as the stashed diff
+        with open(foo_staged.foo_filename, 'w') as foo_file:
+            foo_file.write(FOO_CONTENTS.replace('1', 'b'))
+
+        _test_foo_state(foo_staged, FOO_CONTENTS.replace('1', 'b'), 'AM')
+
+    _test_foo_state(foo_staged, FOO_CONTENTS.replace('1', 'a'), 'AM')
+
+
+@pytest.yield_fixture
+def img_staged(empty_git_dir):
+    with open('.gitignore', 'w') as gitignore_file:
+        gitignore_file.write(C.HOOKS_WORKSPACE + '\n')
+    local['git']['add', '.']()
+    local['git']['commit', '-m', 'add gitignore']()
+
+    img_filename = os.path.join(empty_git_dir, 'img.jpg')
+    shutil.copy(get_resource_path('img1.jpg'), img_filename)
+    local['git']['add', 'img.jpg']()
+    yield auto_namedtuple(path=empty_git_dir, img_filename=img_filename)
+
+
+def _test_img_state(path, expected_file='img1.jpg', status='A'):
+    assert os.path.exists(path.img_filename)
+    assert (
+        open(path.img_filename).read() ==
+        open(get_resource_path(expected_file)).read()
+    )
+    actual_status = get_short_git_status()['img.jpg']
+    assert status == actual_status
+
+
+def test_img_staged(img_staged):
+    _test_img_state(img_staged)
+
+
+def test_img_nothing_unstaged(img_staged, cmd_runner):
+    with staged_files_only(cmd_runner):
+        _test_img_state(img_staged)
+    _test_img_state(img_staged)
+
+
+def test_img_something_unstaged(img_staged, cmd_runner):
+    shutil.copy(get_resource_path('img2.jpg'), img_staged.img_filename)
+
+    _test_img_state(img_staged, 'img2.jpg', 'AM')
+
+    with staged_files_only(cmd_runner):
+        _test_img_state(img_staged)
+
+    _test_img_state(img_staged, 'img2.jpg', 'AM')
+
+
+def test_img_conflict(img_staged, cmd_runner):
+    """Admittedly, this shouldn't happen, but just in case."""
+    shutil.copy(get_resource_path('img2.jpg'), img_staged.img_filename)
+
+    _test_img_state(img_staged, 'img2.jpg', 'AM')
+
+    with staged_files_only(cmd_runner):
+        _test_img_state(img_staged)
+        shutil.copy(get_resource_path('img3.jpg'), img_staged.img_filename)
+        _test_img_state(img_staged, 'img3.jpg', 'AM')
+
+    _test_img_state(img_staged, 'img2.jpg', 'AM')
+
+
+@pytest.yield_fixture
+def submodule_with_commits(empty_git_dir):
+    local['git']['commit', '--allow-empty', '-m', 'foo']()
+    sha1 = local['git']['rev-parse', 'HEAD']().strip()
+    local['git']['commit', '--allow-empty', '-m', 'bar']()
+    sha2 = local['git']['rev-parse', 'HEAD']().strip()
+    yield auto_namedtuple(path=empty_git_dir, sha1=sha1, sha2=sha2)
+
+
+def checkout_submodule(sha):
+    with local.cwd('sub'):
+        local['git']['checkout', sha]()
+
+
+@pytest.yield_fixture
+def sub_staged(submodule_with_commits, empty_git_dir):
+    local['git']['submodule', 'add', submodule_with_commits.path, 'sub']()
+    checkout_submodule(submodule_with_commits.sha1)
+    local['git']['add', 'sub']()
+    yield auto_namedtuple(
+        path=empty_git_dir,
+        sub_path=os.path.join(empty_git_dir, 'sub'),
+        submodule=submodule_with_commits,
+    )
+
+
+def _test_sub_state(path, sha='sha1', status='A'):
+    assert os.path.exists(path.sub_path)
+    with local.cwd(path.sub_path):
+        actual_sha = local['git']['rev-parse', 'HEAD']().strip()
+    assert actual_sha == getattr(path.submodule, sha)
+    actual_status = get_short_git_status()['sub']
+    assert actual_status == status
+
+
+def test_sub_staged(sub_staged):
+    _test_sub_state(sub_staged)
+
+
+def test_sub_nothing_unstaged(sub_staged, cmd_runner):
+    with staged_files_only(cmd_runner):
+        _test_sub_state(sub_staged)
+    _test_sub_state(sub_staged)
+
+
+def test_sub_something_unstaged(sub_staged, cmd_runner):
+    checkout_submodule(sub_staged.submodule.sha2)
+
+    _test_sub_state(sub_staged, 'sha2', 'AM')
+
+    with staged_files_only(cmd_runner):
+        # This is different from others, we don't want to touch subs
+        _test_sub_state(sub_staged, 'sha2', 'AM')
+
+    _test_sub_state(sub_staged, 'sha2', 'AM')