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-rwxr-xr-xthird_party/git/git-p4.py795
1 files changed, 530 insertions, 265 deletions
diff --git a/third_party/git/git-p4.py b/third_party/git/git-p4.py
index 3991e7d1a7..4433ca53de 100755
--- a/third_party/git/git-p4.py
+++ b/third_party/git/git-p4.py
@@ -7,13 +7,21 @@
 #            2007 Trolltech ASA
 # License: MIT <http://www.opensource.org/licenses/mit-license.php>
 #
+# pylint: disable=invalid-name,missing-docstring,too-many-arguments,broad-except
+# pylint: disable=no-self-use,wrong-import-position,consider-iterating-dictionary
+# pylint: disable=wrong-import-order,unused-import,too-few-public-methods
+# pylint: disable=too-many-lines,ungrouped-imports,fixme,too-many-locals
+# pylint: disable=line-too-long,bad-whitespace,superfluous-parens
+# pylint: disable=too-many-statements,too-many-instance-attributes
+# pylint: disable=too-many-branches,too-many-nested-blocks
+#
 import sys
-if sys.hexversion < 0x02040000:
-    # The limiter is the subprocess module
-    sys.stderr.write("git-p4: requires Python 2.4 or later.\n")
+if sys.version_info.major < 3 and sys.version_info.minor < 7:
+    sys.stderr.write("git-p4: requires Python 2.7 or later.\n")
     sys.exit(1)
 import os
 import optparse
+import functools
 import marshal
 import subprocess
 import tempfile
@@ -26,37 +34,17 @@ import zipfile
 import zlib
 import ctypes
 import errno
+import glob
 
+# On python2.7 where raw_input() and input() are both availble,
+# we want raw_input's semantics, but aliased to input for python3
+# compatibility
 # support basestring in python3
 try:
-    unicode = unicode
-except NameError:
-    # 'unicode' is undefined, must be Python 3
-    str = str
-    unicode = str
-    bytes = bytes
-    basestring = (str,bytes)
-else:
-    # 'unicode' exists, must be Python 2
-    str = str
-    unicode = unicode
-    bytes = str
-    basestring = basestring
-
-try:
-    from subprocess import CalledProcessError
-except ImportError:
-    # from python2.7:subprocess.py
-    # Exception classes used by this module.
-    class CalledProcessError(Exception):
-        """This exception is raised when a process run by check_call() returns
-        a non-zero exit status.  The exit status will be stored in the
-        returncode attribute."""
-        def __init__(self, returncode, cmd):
-            self.returncode = returncode
-            self.cmd = cmd
-        def __str__(self):
-            return "Command '%s' returned non-zero exit status %d" % (self.cmd, self.returncode)
+    if raw_input and input:
+        input = raw_input
+except:
+    pass
 
 verbose = False
 
@@ -105,7 +93,7 @@ def p4_build_cmd(cmd):
         # Provide a way to not pass this option by setting git-p4.retries to 0
         real_cmd += ["-r", str(retries)]
 
-    if isinstance(cmd,basestring):
+    if not isinstance(cmd, list):
         real_cmd = ' '.join(real_cmd) + ' ' + cmd
     else:
         real_cmd += cmd
@@ -161,17 +149,135 @@ def calcDiskFree():
         return st.f_bavail * st.f_frsize
 
 def die(msg):
+    """ Terminate execution. Make sure that any running child processes have been wait()ed for before
+        calling this.
+    """
     if verbose:
         raise Exception(msg)
     else:
         sys.stderr.write(msg + "\n")
         sys.exit(1)
 
+def prompt(prompt_text):
+    """ Prompt the user to choose one of the choices
+
+    Choices are identified in the prompt_text by square brackets around
+    a single letter option.
+    """
+    choices = set(m.group(1) for m in re.finditer(r"\[(.)\]", prompt_text))
+    while True:
+        sys.stderr.flush()
+        sys.stdout.write(prompt_text)
+        sys.stdout.flush()
+        response=sys.stdin.readline().strip().lower()
+        if not response:
+            continue
+        response = response[0]
+        if response in choices:
+            return response
+
+# We need different encoding/decoding strategies for text data being passed
+# around in pipes depending on python version
+if bytes is not str:
+    # For python3, always encode and decode as appropriate
+    def decode_text_stream(s):
+        return s.decode() if isinstance(s, bytes) else s
+    def encode_text_stream(s):
+        return s.encode() if isinstance(s, str) else s
+else:
+    # For python2.7, pass read strings as-is, but also allow writing unicode
+    def decode_text_stream(s):
+        return s
+    def encode_text_stream(s):
+        return s.encode('utf_8') if isinstance(s, unicode) else s
+
+def decode_path(path):
+    """Decode a given string (bytes or otherwise) using configured path encoding options
+    """
+    encoding = gitConfig('git-p4.pathEncoding') or 'utf_8'
+    if bytes is not str:
+        return path.decode(encoding, errors='replace') if isinstance(path, bytes) else path
+    else:
+        try:
+            path.decode('ascii')
+        except:
+            path = path.decode(encoding, errors='replace')
+            if verbose:
+                print('Path with non-ASCII characters detected. Used {} to decode: {}'.format(encoding, path))
+        return path
+
+def run_git_hook(cmd, param=[]):
+    """Execute a hook if the hook exists."""
+    if verbose:
+        sys.stderr.write("Looking for hook: %s\n" % cmd)
+        sys.stderr.flush()
+
+    hooks_path = gitConfig("core.hooksPath")
+    if len(hooks_path) <= 0:
+        hooks_path = os.path.join(os.environ["GIT_DIR"], "hooks")
+
+    if not isinstance(param, list):
+        param=[param]
+
+    # resolve hook file name, OS depdenent
+    hook_file = os.path.join(hooks_path, cmd)
+    if platform.system() == 'Windows':
+        if not os.path.isfile(hook_file):
+            # look for the file with an extension
+            files = glob.glob(hook_file + ".*")
+            if not files:
+                return True
+            files.sort()
+            hook_file = files.pop()
+            while hook_file.upper().endswith(".SAMPLE"):
+                # The file is a sample hook. We don't want it
+                if len(files) > 0:
+                    hook_file = files.pop()
+                else:
+                    return True
+
+    if not os.path.isfile(hook_file) or not os.access(hook_file, os.X_OK):
+        return True
+
+    return run_hook_command(hook_file, param) == 0
+
+def run_hook_command(cmd, param):
+    """Executes a git hook command
+       cmd = the command line file to be executed. This can be
+       a file that is run by OS association.
+
+       param = a list of parameters to pass to the cmd command
+
+       On windows, the extension is checked to see if it should
+       be run with the Git for Windows Bash shell.  If there
+       is no file extension, the file is deemed a bash shell
+       and will be handed off to sh.exe. Otherwise, Windows
+       will be called with the shell to handle the file assocation.
+
+       For non Windows operating systems, the file is called
+       as an executable.
+    """
+    cli = [cmd] + param
+    use_shell = False
+    if platform.system() == 'Windows':
+        (root,ext) = os.path.splitext(cmd)
+        if ext == "":
+            exe_path = os.environ.get("EXEPATH")
+            if exe_path is None:
+                exe_path = ""
+            else:
+                exe_path = os.path.join(exe_path, "bin")
+            cli = [os.path.join(exe_path, "SH.EXE")] + cli
+        else:
+            use_shell = True
+    return subprocess.call(cli, shell=use_shell)
+
+
 def write_pipe(c, stdin):
     if verbose:
         sys.stderr.write('Writing pipe: %s\n' % str(c))
 
-    expand = isinstance(c,basestring)
+    expand = not isinstance(c, list)
     p = subprocess.Popen(c, stdin=subprocess.PIPE, shell=expand)
     pipe = p.stdin
     val = pipe.write(stdin)
@@ -183,6 +289,8 @@ def write_pipe(c, stdin):
 
 def p4_write_pipe(c, stdin):
     real_cmd = p4_build_cmd(c)
+    if bytes is not str and isinstance(stdin, str):
+        stdin = encode_text_stream(stdin)
     return write_pipe(real_cmd, stdin)
 
 def read_pipe_full(c):
@@ -193,15 +301,17 @@ def read_pipe_full(c):
     if verbose:
         sys.stderr.write('Reading pipe: %s\n' % str(c))
 
-    expand = isinstance(c,basestring)
+    expand = not isinstance(c, list)
     p = subprocess.Popen(c, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=expand)
     (out, err) = p.communicate()
-    return (p.returncode, out, err)
+    return (p.returncode, out, decode_text_stream(err))
 
-def read_pipe(c, ignore_error=False):
+def read_pipe(c, ignore_error=False, raw=False):
     """ Read output from  command. Returns the output text on
         success. On failure, terminates execution, unless
         ignore_error is True, when it returns an empty string.
+
+        If raw is True, do not attempt to decode output text.
     """
     (retcode, out, err) = read_pipe_full(c)
     if retcode != 0:
@@ -209,6 +319,8 @@ def read_pipe(c, ignore_error=False):
             out = ""
         else:
             die('Command failed: %s\nError: %s' % (str(c), err))
+    if not raw:
+        out = decode_text_stream(out)
     return out
 
 def read_pipe_text(c):
@@ -219,23 +331,22 @@ def read_pipe_text(c):
     if retcode != 0:
         return None
     else:
-        return out.rstrip()
+        return decode_text_stream(out).rstrip()
 
-def p4_read_pipe(c, ignore_error=False):
+def p4_read_pipe(c, ignore_error=False, raw=False):
     real_cmd = p4_build_cmd(c)
-    return read_pipe(real_cmd, ignore_error)
+    return read_pipe(real_cmd, ignore_error, raw=raw)
 
 def read_pipe_lines(c):
     if verbose:
         sys.stderr.write('Reading pipe: %s\n' % str(c))
 
-    expand = isinstance(c, basestring)
+    expand = not isinstance(c, list)
     p = subprocess.Popen(c, stdout=subprocess.PIPE, shell=expand)
     pipe = p.stdout
-    val = pipe.readlines()
+    val = [decode_text_stream(line) for line in pipe.readlines()]
     if pipe.close() or p.wait():
         die('Command failed: %s' % str(c))
-
     return val
 
 def p4_read_pipe_lines(c):
@@ -263,6 +374,7 @@ def p4_has_move_command():
     cmd = p4_build_cmd(["move", "-k", "@from", "@to"])
     p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
     (out, err) = p.communicate()
+    err = decode_text_stream(err)
     # return code will be 1 in either case
     if err.find("Invalid option") >= 0:
         return False
@@ -272,7 +384,7 @@ def p4_has_move_command():
     return True
 
 def system(cmd, ignore_error=False):
-    expand = isinstance(cmd,basestring)
+    expand = not isinstance(cmd, list)
     if verbose:
         sys.stderr.write("executing %s\n" % str(cmd))
     retcode = subprocess.call(cmd, shell=expand)
@@ -284,7 +396,7 @@ def system(cmd, ignore_error=False):
 def p4_system(cmd):
     """Specifically invoke p4 as the system command. """
     real_cmd = p4_build_cmd(cmd)
-    expand = isinstance(real_cmd, basestring)
+    expand = not isinstance(real_cmd, list)
     retcode = subprocess.call(real_cmd, shell=expand)
     if retcode:
         raise CalledProcessError(retcode, real_cmd)
@@ -522,7 +634,7 @@ def getP4OpenedType(file):
 # Return the set of all p4 labels
 def getP4Labels(depotPaths):
     labels = set()
-    if isinstance(depotPaths,basestring):
+    if not isinstance(depotPaths, list):
         depotPaths = [depotPaths]
 
     for l in p4CmdList(["labels"] + ["%s..." % p for p in depotPaths]):
@@ -539,12 +651,7 @@ def getGitTags():
         gitTags.add(tag)
     return gitTags
 
-def diffTreePattern():
-    # This is a simple generator for the diff tree regex pattern. This could be
-    # a class variable if this and parseDiffTreeEntry were a part of a class.
-    pattern = re.compile(':(\d+) (\d+) (\w+) (\w+) ([A-Z])(\d+)?\t(.*?)((\t(.*))|$)')
-    while True:
-        yield pattern
+_diff_tree_pattern = None
 
 def parseDiffTreeEntry(entry):
     """Parses a single diff tree entry into its component elements.
@@ -565,7 +672,11 @@ def parseDiffTreeEntry(entry):
 
     If the pattern is not matched, None is returned."""
 
-    match = diffTreePattern().next().match(entry)
+    global _diff_tree_pattern
+    if not _diff_tree_pattern:
+        _diff_tree_pattern = re.compile(':(\d+) (\d+) (\w+) (\w+) ([A-Z])(\d+)?\t(.*?)((\t(.*))|$)')
+
+    match = _diff_tree_pattern.match(entry)
     if match:
         return {
             'src_mode': match.group(1),
@@ -603,13 +714,21 @@ class P4RequestSizeException(P4ServerException):
         super(P4RequestSizeException, self).__init__(exit_code, p4_result)
         self.limit = limit
 
+class P4CommandException(P4Exception):
+    """ Something went wrong calling p4 which means we have to give up """
+    def __init__(self, msg):
+        self.msg = msg
+
+    def __str__(self):
+        return self.msg
+
 def isModeExecChanged(src_mode, dst_mode):
     return isModeExec(src_mode) != isModeExec(dst_mode)
 
 def p4CmdList(cmd, stdin=None, stdin_mode='w+b', cb=None, skip_info=False,
         errors_as_exceptions=False):
 
-    if isinstance(cmd,basestring):
+    if not isinstance(cmd, list):
         cmd = "-G " + cmd
         expand = True
     else:
@@ -626,11 +745,12 @@ def p4CmdList(cmd, stdin=None, stdin_mode='w+b', cb=None, skip_info=False,
     stdin_file = None
     if stdin is not None:
         stdin_file = tempfile.TemporaryFile(prefix='p4-stdin', mode=stdin_mode)
-        if isinstance(stdin,basestring):
+        if not isinstance(stdin, list):
             stdin_file.write(stdin)
         else:
             for i in stdin:
-                stdin_file.write(i + '\n')
+                stdin_file.write(encode_text_stream(i))
+                stdin_file.write(b'\n')
         stdin_file.flush()
         stdin_file.seek(0)
 
@@ -643,6 +763,20 @@ def p4CmdList(cmd, stdin=None, stdin_mode='w+b', cb=None, skip_info=False,
     try:
         while True:
             entry = marshal.load(p4.stdout)
+            if bytes is not str:
+                # Decode unmarshalled dict to use str keys and values, except for:
+                #   - `data` which may contain arbitrary binary data
+                #   - `depotFile[0-9]*`, `path`, or `clientFile` which may contain non-UTF8 encoded text
+                decoded_entry = {}
+                for key, value in entry.items():
+                    key = key.decode()
+                    if isinstance(value, bytes) and not (key in ('data', 'path', 'clientFile') or key.startswith('depotFile')):
+                        value = value.decode()
+                    decoded_entry[key] = value
+                # Parse out data if it's an error response
+                if decoded_entry.get('code') == 'error' and 'data' in decoded_entry:
+                    decoded_entry['data'] = decoded_entry['data'].decode()
+                entry = decoded_entry
             if skip_info:
                 if 'code' in entry and entry['code'] == 'info':
                     continue
@@ -693,7 +827,8 @@ def p4Where(depotPath):
         if "depotFile" in entry:
             # Search for the base client side depot path, as long as it starts with the branch's P4 path.
             # The base path always ends with "/...".
-            if entry["depotFile"].find(depotPath) == 0 and entry["depotFile"][-4:] == "/...":
+            entry_path = decode_path(entry['depotFile'])
+            if entry_path.find(depotPath) == 0 and entry_path[-4:] == "/...":
                 output = entry
                 break
         elif "data" in entry:
@@ -708,11 +843,11 @@ def p4Where(depotPath):
         return ""
     clientPath = ""
     if "path" in output:
-        clientPath = output.get("path")
+        clientPath = decode_path(output['path'])
     elif "data" in output:
         data = output.get("data")
-        lastSpace = data.rfind(" ")
-        clientPath = data[lastSpace + 1:]
+        lastSpace = data.rfind(b" ")
+        clientPath = decode_path(data[lastSpace + 1:])
 
     if clientPath.endswith("..."):
         clientPath = clientPath[:-3]
@@ -860,6 +995,7 @@ def branch_exists(branch):
     cmd = [ "git", "rev-parse", "--symbolic", "--verify", branch ]
     p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
     out, _ = p.communicate()
+    out = decode_text_stream(out)
     if p.returncode:
         return False
     # expect exactly one line of output: the branch name
@@ -1137,7 +1273,7 @@ class LargeFileSystem(object):
         assert False, "Method 'pushFile' required in " + self.__class__.__name__
 
     def hasLargeFileExtension(self, relPath):
-        return reduce(
+        return functools.reduce(
             lambda a, b: a or b,
             [relPath.endswith('.' + e) for e in gitConfigList('git-p4.largeFileExtensions')],
             False
@@ -1160,13 +1296,11 @@ class LargeFileSystem(object):
             if contentsSize <= gitConfigInt('git-p4.largeFileCompressedThreshold'):
                 return False
             contentTempFile = self.generateTempFile(contents)
-            compressedContentFile = tempfile.NamedTemporaryFile(prefix='git-p4-large-file', delete=False)
-            zf = zipfile.ZipFile(compressedContentFile.name, mode='w')
-            zf.write(contentTempFile, compress_type=zipfile.ZIP_DEFLATED)
-            zf.close()
-            compressedContentsSize = zf.infolist()[0].compress_size
+            compressedContentFile = tempfile.NamedTemporaryFile(prefix='git-p4-large-file', delete=True)
+            with zipfile.ZipFile(compressedContentFile, mode='w') as zf:
+                zf.write(contentTempFile, compress_type=zipfile.ZIP_DEFLATED)
+                compressedContentsSize = zf.infolist()[0].compress_size
             os.remove(contentTempFile)
-            os.remove(compressedContentFile.name)
             if compressedContentsSize > gitConfigInt('git-p4.largeFileCompressedThreshold'):
                 return True
         return False
@@ -1246,7 +1380,7 @@ class GitLFS(LargeFileSystem):
             ['git', 'lfs', 'pointer', '--file=' + contentFile],
             stdout=subprocess.PIPE
         )
-        pointerFile = pointerProcess.stdout.read()
+        pointerFile = decode_text_stream(pointerProcess.stdout.read())
         if pointerProcess.wait():
             os.remove(contentFile)
             die('git-lfs pointer command failed. Did you install the extension?')
@@ -1259,9 +1393,15 @@ class GitLFS(LargeFileSystem):
             pointerFile = re.sub(r'Git LFS pointer for.*\n\n', '', pointerFile)
 
         oid = re.search(r'^oid \w+:(\w+)', pointerFile, re.MULTILINE).group(1)
+        # if someone use external lfs.storage ( not in local repo git )
+        lfs_path = gitConfig('lfs.storage')
+        if not lfs_path:
+            lfs_path = 'lfs'
+        if not os.path.isabs(lfs_path):
+            lfs_path = os.path.join(os.getcwd(), '.git', lfs_path)
         localLargeFile = os.path.join(
-            os.getcwd(),
-            '.git', 'lfs', 'objects', oid[:2], oid[2:4],
+            lfs_path,
+            'objects', oid[:2], oid[2:4],
             oid,
         )
         # LFS Spec states that pointer files should not have the executable bit set.
@@ -1376,14 +1516,14 @@ class P4UserMap:
         for (key, val) in self.users.items():
             s += "%s\t%s\n" % (key.expandtabs(1), val.expandtabs(1))
 
-        open(self.getUserCacheFilename(), "wb").write(s)
+        open(self.getUserCacheFilename(), 'w').write(s)
         self.userMapFromPerforceServer = True
 
     def loadUserMapFromCache(self):
         self.users = {}
         self.userMapFromPerforceServer = False
         try:
-            cache = open(self.getUserCacheFilename(), "rb")
+            cache = open(self.getUserCacheFilename(), 'r')
             lines = cache.readlines()
             cache.close()
             for line in lines:
@@ -1498,13 +1638,39 @@ class P4Submit(Command, P4UserMap):
                                      "work from a local git branch that is not master"),
                 optparse.make_option("--disable-p4sync", dest="disable_p4sync", action="store_true",
                                      help="Skip Perforce sync of p4/master after submit or shelve"),
+                optparse.make_option("--no-verify", dest="no_verify", action="store_true",
+                                     help="Bypass p4-pre-submit and p4-changelist hooks"),
         ]
         self.description = """Submit changes from git to the perforce depot.\n
-    The `p4-pre-submit` hook is executed if it exists and is executable.
-    The hook takes no parameters and nothing from standard input. Exiting with
-    non-zero status from this script prevents `git-p4 submit` from launching.
-
-    One usage scenario is to run unit tests in the hook."""
+    The `p4-pre-submit` hook is executed if it exists and is executable. It
+    can be bypassed with the `--no-verify` command line option. The hook takes
+    no parameters and nothing from standard input. Exiting with a non-zero status
+    from this script prevents `git-p4 submit` from launching.
+
+    One usage scenario is to run unit tests in the hook.
+
+    The `p4-prepare-changelist` hook is executed right after preparing the default
+    changelist message and before the editor is started. It takes one parameter,
+    the name of the file that contains the changelist text. Exiting with a non-zero
+    status from the script will abort the process.
+
+    The purpose of the hook is to edit the message file in place, and it is not
+    supressed by the `--no-verify` option. This hook is called even if
+    `--prepare-p4-only` is set.
+
+    The `p4-changelist` hook is executed after the changelist message has been
+    edited by the user. It can be bypassed with the `--no-verify` option. It
+    takes a single parameter, the name of the file that holds the proposed
+    changelist text. Exiting with a non-zero status causes the command to abort.
+
+    The hook is allowed to edit the changelist file and can be used to normalize
+    the text into some project standard format. It can also be used to refuse the
+    Submit after inspect the message file.
+
+    The `p4-post-changelist` hook is invoked after the submit has successfully
+    occured in P4. It takes no parameters and is meant primarily for notification
+    and cannot affect the outcome of the git p4 submit action.
+    """
 
         self.usage += " [name of git branch to submit into perforce depot]"
         self.origin = ""
@@ -1522,6 +1688,7 @@ class P4Submit(Command, P4UserMap):
         self.exportLabels = False
         self.p4HasMoveCommand = p4_has_move_command()
         self.branch = None
+        self.no_verify = False
 
         if gitConfig('git-p4.largeFileSystem'):
             die("Large file system not supported for git-p4 submit command. Please remove it from config.")
@@ -1660,7 +1827,8 @@ class P4Submit(Command, P4UserMap):
         c = changes[0]
         if c['User'] == newUser: return   # nothing to do
         c['User'] = newUser
-        input = marshal.dumps(c)
+        # p4 does not understand format version 3 and above
+        input = marshal.dumps(c, 2)
 
         result = p4CmdList("change -f -i", stdin=input)
         for r in result:
@@ -1724,7 +1892,7 @@ class P4Submit(Command, P4UserMap):
                 break
         if not change_entry:
             die('Failed to decode output of p4 change -o')
-        for key, value in change_entry.iteritems():
+        for key, value in change_entry.items():
             if key.startswith('File'):
                 if 'depot-paths' in settings:
                     if not [p for p in settings['depot-paths']
@@ -1780,12 +1948,11 @@ class P4Submit(Command, P4UserMap):
         if os.stat(template_file).st_mtime > mtime:
             return True
 
-        while True:
-            response = raw_input("Submit template unchanged. Submit anyway? [y]es, [n]o (skip this patch) ")
-            if response == 'y':
-                return True
-            if response == 'n':
-                return False
+        response = prompt("Submit template unchanged. Submit anyway? [y]es, [n]o (skip this patch) ")
+        if response == 'y':
+            return True
+        if response == 'n':
+            return False
 
     def get_diff_description(self, editedFiles, filesToAdd, symlinks):
         # diff
@@ -1909,6 +2076,9 @@ class P4Submit(Command, P4UserMap):
         applyPatchCmd = patchcmd + "--check --apply -"
         patch_succeeded = True
 
+        if verbose:
+            print("TryPatch: %s" % tryPatchCmd)
+
         if os.system(tryPatchCmd) != 0:
             fixed_rcs_keywords = False
             patch_succeeded = False
@@ -1948,6 +2118,7 @@ class P4Submit(Command, P4UserMap):
                 print("Retrying the patch with RCS keywords cleaned up")
                 if os.system(tryPatchCmd) == 0:
                     patch_succeeded = True
+                    print("Patch succeesed this time with RCS keywords cleaned")
 
         if not patch_succeeded:
             for f in editedFiles:
@@ -2005,58 +2176,76 @@ class P4Submit(Command, P4UserMap):
         tmpFile = os.fdopen(handle, "w+b")
         if self.isWindows:
             submitTemplate = submitTemplate.replace("\n", "\r\n")
-        tmpFile.write(submitTemplate)
+        tmpFile.write(encode_text_stream(submitTemplate))
         tmpFile.close()
 
-        if self.prepare_p4_only:
-            #
-            # Leave the p4 tree prepared, and the submit template around
-            # and let the user decide what to do next
-            #
-            print()
-            print("P4 workspace prepared for submission.")
-            print("To submit or revert, go to client workspace")
-            print("  " + self.clientPath)
-            print()
-            print("To submit, use \"p4 submit\" to write a new description,")
-            print("or \"p4 submit -i <%s\" to use the one prepared by" \
-                  " \"git p4\"." % fileName)
-            print("You can delete the file \"%s\" when finished." % fileName)
-
-            if self.preserveUser and p4User and not self.p4UserIsMe(p4User):
-                print("To preserve change ownership by user %s, you must\n" \
-                      "do \"p4 change -f <change>\" after submitting and\n" \
-                      "edit the User field.")
-            if pureRenameCopy:
-                print("After submitting, renamed files must be re-synced.")
-                print("Invoke \"p4 sync -f\" on each of these files:")
-                for f in pureRenameCopy:
-                    print("  " + f)
-
-            print()
-            print("To revert the changes, use \"p4 revert ...\", and delete")
-            print("the submit template file \"%s\"" % fileName)
-            if filesToAdd:
-                print("Since the commit adds new files, they must be deleted:")
-                for f in filesToAdd:
-                    print("  " + f)
-            print()
-            return True
-
-        #
-        # Let the user edit the change description, then submit it.
-        #
         submitted = False
 
         try:
+            # Allow the hook to edit the changelist text before presenting it
+            # to the user.
+            if not run_git_hook("p4-prepare-changelist", [fileName]):
+                return False
+
+            if self.prepare_p4_only:
+                #
+                # Leave the p4 tree prepared, and the submit template around
+                # and let the user decide what to do next
+                #
+                submitted = True
+                print("")
+                print("P4 workspace prepared for submission.")
+                print("To submit or revert, go to client workspace")
+                print("  " + self.clientPath)
+                print("")
+                print("To submit, use \"p4 submit\" to write a new description,")
+                print("or \"p4 submit -i <%s\" to use the one prepared by" \
+                      " \"git p4\"." % fileName)
+                print("You can delete the file \"%s\" when finished." % fileName)
+
+                if self.preserveUser and p4User and not self.p4UserIsMe(p4User):
+                    print("To preserve change ownership by user %s, you must\n" \
+                          "do \"p4 change -f <change>\" after submitting and\n" \
+                          "edit the User field.")
+                if pureRenameCopy:
+                    print("After submitting, renamed files must be re-synced.")
+                    print("Invoke \"p4 sync -f\" on each of these files:")
+                    for f in pureRenameCopy:
+                        print("  " + f)
+
+                print("")
+                print("To revert the changes, use \"p4 revert ...\", and delete")
+                print("the submit template file \"%s\"" % fileName)
+                if filesToAdd:
+                    print("Since the commit adds new files, they must be deleted:")
+                    for f in filesToAdd:
+                        print("  " + f)
+                print("")
+                sys.stdout.flush()
+                return True
+
             if self.edit_template(fileName):
+                if not self.no_verify:
+                    if not run_git_hook("p4-changelist", [fileName]):
+                        print("The p4-changelist hook failed.")
+                        sys.stdout.flush()
+                        return False
+
                 # read the edited message and submit
                 tmpFile = open(fileName, "rb")
-                message = tmpFile.read()
+                message = decode_text_stream(tmpFile.read())
                 tmpFile.close()
                 if self.isWindows:
                     message = message.replace("\r\n", "\n")
-                submitTemplate = message[:message.index(separatorLine)]
+                if message.find(separatorLine) != -1:
+                    submitTemplate = message[:message.index(separatorLine)]
+                else:
+                    submitTemplate = message
+
+                if len(submitTemplate.strip()) == 0:
+                    print("Changelist is empty, aborting this changelist.")
+                    sys.stdout.flush()
+                    return False
 
                 if update_shelve:
                     p4_write_pipe(['shelve', '-r', '-i'], submitTemplate)
@@ -2079,20 +2268,23 @@ class P4Submit(Command, P4UserMap):
 
                 submitted = True
 
+                run_git_hook("p4-post-changelist")
         finally:
-            # skip this patch
+            # Revert changes if we skip this patch
             if not submitted or self.shelve:
                 if self.shelve:
                     print ("Reverting shelved files.")
                 else:
                     print ("Submission cancelled, undoing p4 changes.")
+                sys.stdout.flush()
                 for f in editedFiles | filesToDelete:
                     p4_revert(f)
                 for f in filesToAdd:
                     p4_revert(f)
                     os.remove(f)
 
-        os.remove(fileName)
+            if not self.prepare_p4_only:
+                os.remove(fileName)
         return submitted
 
     # Export git tags as p4 labels. Create a p4 label and then tag
@@ -2316,13 +2508,17 @@ class P4Submit(Command, P4UserMap):
             sys.exit("number of commits (%d) must match number of shelved changelist (%d)" %
                      (len(commits), num_shelves))
 
-        hooks_path = gitConfig("core.hooksPath")
-        if len(hooks_path) <= 0:
-            hooks_path = os.path.join(os.environ.get("GIT_DIR", ".git"), "hooks")
-
-        hook_file = os.path.join(hooks_path, "p4-pre-submit")
-        if os.path.isfile(hook_file) and os.access(hook_file, os.X_OK) and subprocess.call([hook_file]) != 0:
-            sys.exit(1)
+        if not self.no_verify:
+            try:
+                if not run_git_hook("p4-pre-submit"):
+                    print("\nThe p4-pre-submit hook failed, aborting the submit.\n\nYou can skip " \
+                        "this pre-submission check by adding\nthe command line option '--no-verify', " \
+                        "however,\nthis will also skip the p4-changelist hook as well.")
+                    sys.exit(1)
+            except Exception as e:
+                print("\nThe p4-pre-submit hook failed, aborting the submit.\n\nThe hook failed "\
+                    "with the error '{0}'".format(e.message) )
+                sys.exit(1)
 
         #
         # Apply the commits, one at a time.  On failure, ask if should
@@ -2341,37 +2537,29 @@ class P4Submit(Command, P4UserMap):
                 ok = self.applyCommit(commit)
             if ok:
                 applied.append(commit)
-            else:
-                if self.prepare_p4_only and i < last:
-                    print("Processing only the first commit due to option" \
-                          " --prepare-p4-only")
+                if self.prepare_p4_only:
+                    if i < last:
+                        print("Processing only the first commit due to option" \
+                                " --prepare-p4-only")
                     break
+            else:
                 if i < last:
-                    quit = False
-                    while True:
-                        # prompt for what to do, or use the option/variable
-                        if self.conflict_behavior == "ask":
-                            print("What do you want to do?")
-                            response = raw_input("[s]kip this commit but apply"
-                                                 " the rest, or [q]uit? ")
-                            if not response:
-                                continue
-                        elif self.conflict_behavior == "skip":
-                            response = "s"
-                        elif self.conflict_behavior == "quit":
-                            response = "q"
-                        else:
-                            die("Unknown conflict_behavior '%s'" %
-                                self.conflict_behavior)
-
-                        if response[0] == "s":
-                            print("Skipping this commit, but applying the rest")
-                            break
-                        if response[0] == "q":
-                            print("Quitting")
-                            quit = True
-                            break
-                    if quit:
+                    # prompt for what to do, or use the option/variable
+                    if self.conflict_behavior == "ask":
+                        print("What do you want to do?")
+                        response = prompt("[s]kip this commit but apply the rest, or [q]uit? ")
+                    elif self.conflict_behavior == "skip":
+                        response = "s"
+                    elif self.conflict_behavior == "quit":
+                        response = "q"
+                    else:
+                        die("Unknown conflict_behavior '%s'" %
+                            self.conflict_behavior)
+
+                    if response == "s":
+                        print("Skipping this commit, but applying the rest")
+                    if response == "q":
+                        print("Quitting")
                         break
 
         chdir(self.oldWorkingDirectory)
@@ -2481,7 +2669,7 @@ class View(object):
 
     def convert_client_path(self, clientFile):
         # chop off //client/ part to make it relative
-        if not clientFile.startswith(self.client_prefix):
+        if not decode_path(clientFile).startswith(self.client_prefix):
             die("No prefix '%s' on clientFile '%s'" %
                 (self.client_prefix, clientFile))
         return clientFile[len(self.client_prefix):]
@@ -2490,7 +2678,7 @@ class View(object):
         """ Caching file paths by "p4 where" batch query """
 
         # List depot file paths exclude that already cached
-        fileArgs = [f['path'] for f in files if f['path'] not in self.client_spec_path_cache]
+        fileArgs = [f['path'] for f in files if decode_path(f['path']) not in self.client_spec_path_cache]
 
         if len(fileArgs) == 0:
             return  # All files in cache
@@ -2505,16 +2693,18 @@ class View(object):
             if "unmap" in res:
                 # it will list all of them, but only one not unmap-ped
                 continue
+            depot_path = decode_path(res['depotFile'])
             if gitConfigBool("core.ignorecase"):
-                res['depotFile'] = res['depotFile'].lower()
-            self.client_spec_path_cache[res['depotFile']] = self.convert_client_path(res["clientFile"])
+                depot_path = depot_path.lower()
+            self.client_spec_path_cache[depot_path] = self.convert_client_path(res["clientFile"])
 
         # not found files or unmap files set to ""
         for depotFile in fileArgs:
+            depotFile = decode_path(depotFile)
             if gitConfigBool("core.ignorecase"):
                 depotFile = depotFile.lower()
             if depotFile not in self.client_spec_path_cache:
-                self.client_spec_path_cache[depotFile] = ""
+                self.client_spec_path_cache[depotFile] = b''
 
     def map_in_client(self, depot_path):
         """Return the relative location in the client where this
@@ -2619,6 +2809,7 @@ class P4Sync(Command, P4UserMap):
     def checkpoint(self):
         self.gitStream.write("checkpoint\n\n")
         self.gitStream.write("progress checkpoint\n\n")
+        self.gitStream.flush()
         out = self.gitOutput.readline()
         if self.verbose:
             print("checkpoint finished: " + out)
@@ -2632,7 +2823,7 @@ class P4Sync(Command, P4UserMap):
             elif path.lower() == p.lower():
                 return False
         for p in self.depotPaths:
-            if p4PathStartsWith(path, p):
+            if p4PathStartsWith(path, decode_path(p)):
                 return True
         return False
 
@@ -2641,7 +2832,7 @@ class P4Sync(Command, P4UserMap):
         fnum = 0
         while "depotFile%s" % fnum in commit:
             path =  commit["depotFile%s" % fnum]
-            found = self.isPathWanted(path)
+            found = self.isPathWanted(decode_path(path))
             if not found:
                 fnum = fnum + 1
                 continue
@@ -2675,7 +2866,7 @@ class P4Sync(Command, P4UserMap):
         if self.useClientSpec:
             # branch detection moves files up a level (the branch name)
             # from what client spec interpretation gives
-            path = self.clientSpecDirs.map_in_client(path)
+            path = decode_path(self.clientSpecDirs.map_in_client(path))
             if self.detectBranches:
                 for b in self.knownBranches:
                     if p4PathStartsWith(path, b + "/"):
@@ -2709,14 +2900,15 @@ class P4Sync(Command, P4UserMap):
         branches = {}
         fnum = 0
         while "depotFile%s" % fnum in commit:
-            path =  commit["depotFile%s" % fnum]
+            raw_path = commit["depotFile%s" % fnum]
+            path = decode_path(raw_path)
             found = self.isPathWanted(path)
             if not found:
                 fnum = fnum + 1
                 continue
 
             file = {}
-            file["path"] = path
+            file["path"] = raw_path
             file["rev"] = commit["rev%s" % fnum]
             file["action"] = commit["action%s" % fnum]
             file["type"] = commit["type%s" % fnum]
@@ -2725,7 +2917,7 @@ class P4Sync(Command, P4UserMap):
             # start with the full relative path where this file would
             # go in a p4 client
             if self.useClientSpec:
-                relPath = self.clientSpecDirs.map_in_client(path)
+                relPath = decode_path(self.clientSpecDirs.map_in_client(path))
             else:
                 relPath = self.stripRepoPath(path, self.depotPaths)
 
@@ -2741,7 +2933,7 @@ class P4Sync(Command, P4UserMap):
         return branches
 
     def writeToGitStream(self, gitMode, relPath, contents):
-        self.gitStream.write('M %s inline %s\n' % (gitMode, relPath))
+        self.gitStream.write(encode_text_stream(u'M {} inline {}\n'.format(gitMode, relPath)))
         self.gitStream.write('data %d\n' % sum(len(d) for d in contents))
         for d in contents:
             self.gitStream.write(d)
@@ -2763,14 +2955,15 @@ class P4Sync(Command, P4UserMap):
     # - helper for streamP4Files
 
     def streamOneP4File(self, file, contents):
-        relPath = self.stripRepoPath(file['depotFile'], self.branchPrefixes)
-        relPath = self.encodeWithUTF8(relPath)
+        file_path = file['depotFile']
+        relPath = self.stripRepoPath(decode_path(file_path), self.branchPrefixes)
+
         if verbose:
             if 'fileSize' in self.stream_file:
                 size = int(self.stream_file['fileSize'])
             else:
                 size = 0 # deleted files don't get a fileSize apparently
-            sys.stdout.write('\r%s --> %s (%i MB)\n' % (file['depotFile'], relPath, size/1024/1024))
+            sys.stdout.write('\r%s --> %s (%i MB)\n' % (file_path, relPath, size/1024/1024))
             sys.stdout.flush()
 
         (type_base, type_mods) = split_p4_type(file["type"])
@@ -2782,13 +2975,13 @@ class P4Sync(Command, P4UserMap):
             git_mode = "120000"
             # p4 print on a symlink sometimes contains "target\n";
             # if it does, remove the newline
-            data = ''.join(contents)
+            data = ''.join(decode_text_stream(c) for c in contents)
             if not data:
                 # Some version of p4 allowed creating a symlink that pointed
                 # to nothing.  This causes p4 errors when checking out such
                 # a change, and errors here too.  Work around it by ignoring
                 # the bad symlink; hopefully a future change fixes it.
-                print("\nIgnoring empty symlink in %s" % file['depotFile'])
+                print("\nIgnoring empty symlink in %s" % file_path)
                 return
             elif data[-1] == '\n':
                 contents = [data[:-1]]
@@ -2807,7 +3000,7 @@ class P4Sync(Command, P4UserMap):
             # just the native "NT" type.
             #
             try:
-                text = p4_read_pipe(['print', '-q', '-o', '-', '%s@%s' % (file['depotFile'], file['change'])])
+                text = p4_read_pipe(['print', '-q', '-o', '-', '%s@%s' % (decode_path(file['depotFile']), file['change'])], raw=True)
             except Exception as e:
                 if 'Translation of file content failed' in str(e):
                     type_base = 'binary'
@@ -2815,7 +3008,7 @@ class P4Sync(Command, P4UserMap):
                     raise e
             else:
                 if p4_version_string().find('/NT') >= 0:
-                    text = text.replace('\r\n', '\n')
+                    text = text.replace(b'\r\n', b'\n')
                 contents = [ text ]
 
         if type_base == "apple":
@@ -2836,7 +3029,7 @@ class P4Sync(Command, P4UserMap):
         pattern = p4_keywords_regexp_for_type(type_base, type_mods)
         if pattern:
             regexp = re.compile(pattern, re.VERBOSE)
-            text = ''.join(contents)
+            text = ''.join(decode_text_stream(c) for c in contents)
             text = regexp.sub(r'$\1$', text)
             contents = [ text ]
 
@@ -2846,12 +3039,11 @@ class P4Sync(Command, P4UserMap):
         self.writeToGitStream(git_mode, relPath, contents)
 
     def streamOneP4Deletion(self, file):
-        relPath = self.stripRepoPath(file['path'], self.branchPrefixes)
-        relPath = self.encodeWithUTF8(relPath)
+        relPath = self.stripRepoPath(decode_path(file['path']), self.branchPrefixes)
         if verbose:
             sys.stdout.write("delete %s\n" % relPath)
             sys.stdout.flush()
-        self.gitStream.write("D %s\n" % relPath)
+        self.gitStream.write(encode_text_stream(u'D {}\n'.format(relPath)))
 
         if self.largeFileSystem and self.largeFileSystem.isLargeFile(relPath):
             self.largeFileSystem.removeLargeFile(relPath)
@@ -2951,9 +3143,9 @@ class P4Sync(Command, P4UserMap):
                 if 'shelved_cl' in f:
                     # Handle shelved CLs using the "p4 print file@=N" syntax to print
                     # the contents
-                    fileArg = '%s@=%d' % (f['path'], f['shelved_cl'])
+                    fileArg = f['path'] + encode_text_stream('@={}'.format(f['shelved_cl']))
                 else:
-                    fileArg = '%s#%s' % (f['path'], f['rev'])
+                    fileArg = f['path'] + encode_text_stream('#{}'.format(f['rev']))
 
                 fileArgs.append(fileArg)
 
@@ -3023,6 +3215,42 @@ class P4Sync(Command, P4UserMap):
             print('Ignoring file outside of prefix: {0}'.format(path))
         return hasPrefix
 
+    def findShadowedFiles(self, files, change):
+        # Perforce allows you commit files and directories with the same name,
+        # so you could have files //depot/foo and //depot/foo/bar both checked
+        # in.  A p4 sync of a repository in this state fails.  Deleting one of
+        # the files recovers the repository.
+        #
+        # Git will not allow the broken state to exist and only the most recent
+        # of the conflicting names is left in the repository.  When one of the
+        # conflicting files is deleted we need to re-add the other one to make
+        # sure the git repository recovers in the same way as perforce.
+        deleted = [f for f in files if f['action'] in self.delete_actions]
+        to_check = set()
+        for f in deleted:
+            path = decode_path(f['path'])
+            to_check.add(path + '/...')
+            while True:
+                path = path.rsplit("/", 1)[0]
+                if path == "/" or path in to_check:
+                    break
+                to_check.add(path)
+        to_check = ['%s@%s' % (wildcard_encode(p), change) for p in to_check
+            if self.hasBranchPrefix(p)]
+        if to_check:
+            stat_result = p4CmdList(["-x", "-", "fstat", "-T",
+                "depotFile,headAction,headRev,headType"], stdin=to_check)
+            for record in stat_result:
+                if record['code'] != 'stat':
+                    continue
+                if record['headAction'] in self.delete_actions:
+                    continue
+                files.append({
+                    'action': 'add',
+                    'path': record['depotFile'],
+                    'rev': record['headRev'],
+                    'type': record['headType']})
+
     def commit(self, details, files, branch, parent = "", allow_empty=False):
         epoch = details["time"]
         author = details["user"]
@@ -3031,11 +3259,14 @@ class P4Sync(Command, P4UserMap):
         if self.verbose:
             print('commit into {0}'.format(branch))
 
+        files = [f for f in files
+            if self.hasBranchPrefix(decode_path(f['path']))]
+        self.findShadowedFiles(files, details['change'])
+
         if self.clientSpecDirs:
             self.clientSpecDirs.update_client_spec_path_cache(files)
 
-        files = [f for f in files
-            if self.inClientSpec(f['path']) and self.hasBranchPrefix(f['path'])]
+        files = [f for f in files if self.inClientSpec(decode_path(f['path']))]
 
         if gitConfigBool('git-p4.keepEmptyCommits'):
             allow_empty = True
@@ -3525,10 +3756,79 @@ class P4Sync(Command, P4UserMap):
         self.updateOptionDict(details)
         try:
             self.commit(details, self.extractFilesFromCommit(details), self.branch)
-        except IOError:
+        except IOError as err:
             print("IO error with git fast-import. Is your git version recent enough?")
+            print("IO error details: {}".format(err))
             print(self.gitError.read())
 
+
+    def importRevisions(self, args, branch_arg_given):
+        changes = []
+
+        if len(self.changesFile) > 0:
+            with open(self.changesFile) as f:
+                output = f.readlines()
+            changeSet = set()
+            for line in output:
+                changeSet.add(int(line))
+
+            for change in changeSet:
+                changes.append(change)
+
+            changes.sort()
+        else:
+            # catch "git p4 sync" with no new branches, in a repo that
+            # does not have any existing p4 branches
+            if len(args) == 0:
+                if not self.p4BranchesInGit:
+                    raise P4CommandException("No remote p4 branches.  Perhaps you never did \"git p4 clone\" in here.")
+
+                # The default branch is master, unless --branch is used to
+                # specify something else.  Make sure it exists, or complain
+                # nicely about how to use --branch.
+                if not self.detectBranches:
+                    if not branch_exists(self.branch):
+                        if branch_arg_given:
+                            raise P4CommandException("Error: branch %s does not exist." % self.branch)
+                        else:
+                            raise P4CommandException("Error: no branch %s; perhaps specify one with --branch." %
+                                self.branch)
+
+            if self.verbose:
+                print("Getting p4 changes for %s...%s" % (', '.join(self.depotPaths),
+                                                          self.changeRange))
+            changes = p4ChangesForPaths(self.depotPaths, self.changeRange, self.changes_block_size)
+
+            if len(self.maxChanges) > 0:
+                changes = changes[:min(int(self.maxChanges), len(changes))]
+
+        if len(changes) == 0:
+            if not self.silent:
+                print("No changes to import!")
+        else:
+            if not self.silent and not self.detectBranches:
+                print("Import destination: %s" % self.branch)
+
+            self.updatedBranches = set()
+
+            if not self.detectBranches:
+                if args:
+                    # start a new branch
+                    self.initialParent = ""
+                else:
+                    # build on a previous revision
+                    self.initialParent = parseRevision(self.branch)
+
+            self.importChanges(changes)
+
+            if not self.silent:
+                print("")
+                if len(self.updatedBranches) > 0:
+                    sys.stdout.write("Updated branches: ")
+                    for b in self.updatedBranches:
+                        sys.stdout.write("%s " % b)
+                    sys.stdout.write("\n")
+
     def openStreams(self):
         self.importProcess = subprocess.Popen(["git", "fast-import"],
                                               stdin=subprocess.PIPE,
@@ -3538,12 +3838,24 @@ class P4Sync(Command, P4UserMap):
         self.gitStream = self.importProcess.stdin
         self.gitError = self.importProcess.stderr
 
+        if bytes is not str:
+            # Wrap gitStream.write() so that it can be called using `str` arguments
+            def make_encoded_write(write):
+                def encoded_write(s):
+                    return write(s.encode() if isinstance(s, str) else s)
+                return encoded_write
+
+            self.gitStream.write = make_encoded_write(self.gitStream.write)
+
     def closeStreams(self):
+        if self.gitStream is None:
+            return
         self.gitStream.close()
         if self.importProcess.wait() != 0:
             die("fast-import failed: %s" % self.gitError.read())
         self.gitOutput.close()
         self.gitError.close()
+        self.gitStream = None
 
     def run(self, args):
         if self.importIntoRemotes:
@@ -3727,87 +4039,36 @@ class P4Sync(Command, P4UserMap):
                     b = b[len(self.projectName):]
                 self.createdBranches.add(b)
 
-        self.openStreams()
-
-        if revision:
-            self.importHeadRevision(revision)
-        else:
-            changes = []
-
-            if len(self.changesFile) > 0:
-                output = open(self.changesFile).readlines()
-                changeSet = set()
-                for line in output:
-                    changeSet.add(int(line))
-
-                for change in changeSet:
-                    changes.append(change)
-
-                changes.sort()
-            else:
-                # catch "git p4 sync" with no new branches, in a repo that
-                # does not have any existing p4 branches
-                if len(args) == 0:
-                    if not self.p4BranchesInGit:
-                        die("No remote p4 branches.  Perhaps you never did \"git p4 clone\" in here.")
-
-                    # The default branch is master, unless --branch is used to
-                    # specify something else.  Make sure it exists, or complain
-                    # nicely about how to use --branch.
-                    if not self.detectBranches:
-                        if not branch_exists(self.branch):
-                            if branch_arg_given:
-                                die("Error: branch %s does not exist." % self.branch)
-                            else:
-                                die("Error: no branch %s; perhaps specify one with --branch." %
-                                    self.branch)
+        p4_check_access()
 
-                if self.verbose:
-                    print("Getting p4 changes for %s...%s" % (', '.join(self.depotPaths),
-                                                              self.changeRange))
-                changes = p4ChangesForPaths(self.depotPaths, self.changeRange, self.changes_block_size)
+        self.openStreams()
 
-                if len(self.maxChanges) > 0:
-                    changes = changes[:min(int(self.maxChanges), len(changes))]
+        err = None
 
-            if len(changes) == 0:
-                if not self.silent:
-                    print("No changes to import!")
+        try:
+            if revision:
+                self.importHeadRevision(revision)
             else:
-                if not self.silent and not self.detectBranches:
-                    print("Import destination: %s" % self.branch)
+                self.importRevisions(args, branch_arg_given)
 
-                self.updatedBranches = set()
+            if gitConfigBool("git-p4.importLabels"):
+                self.importLabels = True
 
-                if not self.detectBranches:
-                    if args:
-                        # start a new branch
-                        self.initialParent = ""
-                    else:
-                        # build on a previous revision
-                        self.initialParent = parseRevision(self.branch)
+            if self.importLabels:
+                p4Labels = getP4Labels(self.depotPaths)
+                gitTags = getGitTags()
 
-                self.importChanges(changes)
+                missingP4Labels = p4Labels - gitTags
+                self.importP4Labels(self.gitStream, missingP4Labels)
 
-                if not self.silent:
-                    print("")
-                    if len(self.updatedBranches) > 0:
-                        sys.stdout.write("Updated branches: ")
-                        for b in self.updatedBranches:
-                            sys.stdout.write("%s " % b)
-                        sys.stdout.write("\n")
-
-        if gitConfigBool("git-p4.importLabels"):
-            self.importLabels = True
-
-        if self.importLabels:
-            p4Labels = getP4Labels(self.depotPaths)
-            gitTags = getGitTags()
+        except P4CommandException as e:
+            err = e
 
-            missingP4Labels = p4Labels - gitTags
-            self.importP4Labels(self.gitStream, missingP4Labels)
+        finally:
+            self.closeStreams()
 
-        self.closeStreams()
+        if err:
+            die(str(err))
 
         # Cleanup temporary branches created during import
         if self.tempBranches != []:
@@ -3976,7 +4237,7 @@ class P4Unshelve(Command):
         """
 
         for parent in (range(65535)):
-            log = extractLogMessageFromGitCommit("{0}^{1}".format(starting_point, parent))
+            log = extractLogMessageFromGitCommit("{0}~{1}".format(starting_point, parent))
             settings = extractSettingsGitLog(log)
             if 'change' in settings:
                 return settings
@@ -4111,7 +4372,6 @@ commands = {
     "unshelve" : P4Unshelve,
 }
 
-
 def main():
     if len(sys.argv[1:]) == 0:
         printUsage(commands.keys())
@@ -4141,7 +4401,12 @@ def main():
                                    description = cmd.description,
                                    formatter = HelpFormatter())
 
-    (cmd, args) = parser.parse_args(sys.argv[2:], cmd);
+    try:
+        (cmd, args) = parser.parse_args(sys.argv[2:], cmd);
+    except:
+        parser.print_help()
+        raise
+
     global verbose
     verbose = cmd.verbose
     if cmd.needsGit: