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Message #00022
[PATCH] plainbox:clitools: work around argparse changes in 3.3.4
This patch adds a work-around for build failures spotted on Ubuntu
14.04 on the 28th of January 2014. We believe that those failures were
caused by the recent upload of python 3.3.4 which included updates to
the standard library argparse module. Those changes caused slight change
in the contents of the command usage help message.
For consistency with Ubuntu 12.04 which is our officially supported
target we're bundling a small fragment of argparse from python 3.3.1,
specifically the HelpFormatter._format_usage() method, along with
appropriate explanation and possible deprecation strategy.
The bundled fragment was written by:
Steven J. Bethard <steven.bethard@xxxxxxxxx>.
It is covered by the PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2.
Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@xxxxxxxxxxxxx>
---
plainbox/plainbox/impl/_argparse.py | 227 ++++++++++++++++++++++++++++++++++++
plainbox/plainbox/impl/clitools.py | 5 +-
2 files changed, 231 insertions(+), 1 deletion(-)
create mode 100644 plainbox/plainbox/impl/_argparse.py
diff --git a/plainbox/plainbox/impl/_argparse.py b/plainbox/plainbox/impl/_argparse.py
new file mode 100644
index 0000000..ea0c63e
--- /dev/null
+++ b/plainbox/plainbox/impl/_argparse.py
@@ -0,0 +1,227 @@
+# This file is part of Checkbox.
+#
+# Copyright 2013 Canonical Ltd.
+# Written by:
+# Zygmunt Krynicki <zygmunt.krynicki@xxxxxxxxxxxxx>
+#
+# Checkbox is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 3,
+# as published by the Free Software Foundation.
+#
+# Checkbox is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Checkbox. If not, see <http://www.gnu.org/licenses/>.
+#
+# Parts copied from Python3.3.1:
+# Steven J. Bethard <steven.bethard@xxxxxxxxx>.
+#
+# PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2
+# --------------------------------------------
+#
+# 1. This LICENSE AGREEMENT is between the Python Software Foundation ("PSF"),
+# and the Individual or Organization ("Licensee") accessing and otherwise
+# using this software ("Python") in source or binary form and its associated
+# documentation.
+#
+# 2. Subject to the terms and conditions of this License Agreement, PSF hereby
+# grants Licensee a nonexclusive, royalty-free, world-wide license to
+# reproduce, analyze, test, perform and/or display publicly, prepare
+# derivative works, distribute, and otherwise use Python alone or in any
+# derivative version, provided, however, that PSF's License Agreement and
+# PSF's notice of copyright, i.e., "Copyright (c) 2001, 2002, 2003, 2004,
+# 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014 Python Software
+# Foundation; All Rights Reserved" are retained in Python alone or in any
+# derivative version prepared by Licensee.
+#
+# 3. In the event Licensee prepares a derivative work that is based on or
+# incorporates Python or any part thereof, and wants to make the derivative
+# work available to others as provided herein, then Licensee hereby agrees
+# to include in any such work a brief summary of the changes made to Python.
+#
+# 4. PSF is making Python available to Licensee on an "AS IS" basis. PSF MAKES
+# NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED. BY WAY OF EXAMPLE,
+# BUT NOT LIMITATION, PSF MAKES NO AND DISCLAIMS ANY REPRESENTATION OR
+# WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT
+# THE USE OF PYTHON WILL NOT INFRINGE ANY THIRD PARTY RIGHTS.
+#
+# 5. PSF SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON FOR ANY
+# INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS A RESULT OF
+# MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON, OR ANY DERIVATIVE
+# THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.
+#
+# 6. This License Agreement will automatically terminate upon a material breach
+# of its terms and conditions.
+#
+# 7. Nothing in this License Agreement shall be deemed to create any
+# relationship of agency, partnership, or joint venture between PSF and
+# Licensee. This License Agreement does not grant permission to use PSF
+# trademarks or trade name in a trademark sense to endorse or promote
+# products or services of Licensee, or any third party.
+#
+# 8. By copying, installing or otherwise using Python, Licensee agrees to be
+# bound by the terms and conditions of this License Agreement.
+
+"""
+:mod:`plainbox.impl._argparse` -- support code for argparse compatibility
+=========================================================================
+
+This module contains a copy of argparse source code from python3.3.1. It is
+required for compatibility as argparse keeps having subtle changes in behavior
+across releases.
+"""
+
+import argparse
+
+
+class LegacyHelpFormatter(argparse.HelpFormatter):
+ """
+ Vanilla copy of argparse.HelpFormatter from python 3.3.1
+
+ This class retains the behavior of argparse as seen on that version of
+ python. This is done for compatibility and for perfectly identical output
+ of PlainBox on various versions of python 3.x.
+
+ Investigation after a rather odd test failure lead to this diff::
+
+ --- raring/argparse.py 2014-01-28 18:52:35.789316074 +0100
+ +++ trusty/argparse.py 2014-01-28 19:11:19.121282883 +0100
+ @@ -174,6 +174,8 @@
+ self._prog = prog
+ self._indent_increment = indent_increment
+ self._max_help_position = max_help_position
+ + self._max_help_position = min(max_help_position,
+ + max(width - 20, indent_increment * 2))
+ self._width = width
+
+ self._current_indent = 0
+ @@ -345,7 +347,7 @@
+ else:
+ line_len = len(indent) - 1
+ for part in parts:
+ - if line_len + 1 + len(part) > text_width:
+ + if line_len + 1 + len(part) > text_width and line:
+ lines.append(indent + ' '.join(line))
+ line = []
+ line_len = len(indent) - 1
+ @@ -485,7 +487,7 @@
+ def _format_text(self, text):
+ if '%(prog)' in text:
+ text = text % dict(prog=self._prog)
+ - text_width = self._width - self._current_indent
+ + text_width = max(self._width - self._current_indent, 11)
+ indent = ' ' * self._current_indent
+ return self._fill_text(text, text_width, indent) + '\n\n'
+
+ @@ -493,7 +495,7 @@
+ # determine the required width and the entry label
+ help_position = min(self._action_max_length + 2,
+ self._max_help_position)
+ - help_width = self._width - help_position
+ + help_width = max(self._width - help_position, 11)
+ action_width = help_position - self._current_indent - 2
+ action_header = self._format_action_invocation(action)
+
+ The relevant part is the second change, involving the addition of ``and line``.
+ It causes a line not to be printed, where it otherwise would. Since this is
+ a minor visual change we chose to retain the current behavior.
+
+ In the future, especially when python3.4 is the base version and older
+ versions are not supported, a reverse patch might be applied and held here,
+ to provide the non-legacy behavior.
+ """
+
+ def _format_usage(self, usage, actions, groups, prefix):
+ if prefix is None:
+ prefix = argparse._('usage: ')
+
+ # if usage is specified, use that
+ if usage is not None:
+ usage = usage % dict(prog=self._prog)
+
+ # if no optionals or positionals are available, usage is just prog
+ elif usage is None and not actions:
+ usage = '%(prog)s' % dict(prog=self._prog)
+
+ # if optionals and positionals are available, calculate usage
+ elif usage is None:
+ prog = '%(prog)s' % dict(prog=self._prog)
+
+ # split optionals from positionals
+ optionals = []
+ positionals = []
+ for action in actions:
+ if action.option_strings:
+ optionals.append(action)
+ else:
+ positionals.append(action)
+
+ # build full usage string
+ format = self._format_actions_usage
+ action_usage = format(optionals + positionals, groups)
+ usage = ' '.join([s for s in [prog, action_usage] if s])
+
+ # wrap the usage parts if it's too long
+ text_width = self._width - self._current_indent
+ if len(prefix) + len(usage) > text_width:
+
+ # break usage into wrappable parts
+ part_regexp = r'\(.*?\)+|\[.*?\]+|\S+'
+ opt_usage = format(optionals, groups)
+ pos_usage = format(positionals, groups)
+ opt_parts = argparse._re.findall(part_regexp, opt_usage)
+ pos_parts = argparse._re.findall(part_regexp, pos_usage)
+ assert ' '.join(opt_parts) == opt_usage
+ assert ' '.join(pos_parts) == pos_usage
+
+ # helper for wrapping lines
+ def get_lines(parts, indent, prefix=None):
+ lines = []
+ line = []
+ if prefix is not None:
+ line_len = len(prefix) - 1
+ else:
+ line_len = len(indent) - 1
+ for part in parts:
+ if line_len + 1 + len(part) > text_width:
+ lines.append(indent + ' '.join(line))
+ line = []
+ line_len = len(indent) - 1
+ line.append(part)
+ line_len += len(part) + 1
+ if line:
+ lines.append(indent + ' '.join(line))
+ if prefix is not None:
+ lines[0] = lines[0][len(indent):]
+ return lines
+
+ # if prog is short, follow it with optionals or positionals
+ if len(prefix) + len(prog) <= 0.75 * text_width:
+ indent = ' ' * (len(prefix) + len(prog) + 1)
+ if opt_parts:
+ lines = get_lines([prog] + opt_parts, indent, prefix)
+ lines.extend(get_lines(pos_parts, indent))
+ elif pos_parts:
+ lines = get_lines([prog] + pos_parts, indent, prefix)
+ else:
+ lines = [prog]
+
+ # if prog is long, put it on its own line
+ else:
+ indent = ' ' * len(prefix)
+ parts = opt_parts + pos_parts
+ lines = get_lines(parts, indent)
+ if len(lines) > 1:
+ lines = []
+ lines.extend(get_lines(opt_parts, indent))
+ lines.extend(get_lines(pos_parts, indent))
+ lines = [prog] + lines
+
+ # join lines into usage
+ usage = '\n'.join(lines)
+
+ # prefix with 'usage:'
+ return '%s%s\n\n' % (prefix, usage)
diff --git a/plainbox/plainbox/impl/clitools.py b/plainbox/plainbox/impl/clitools.py
index e6553da..a87dd30 100644
--- a/plainbox/plainbox/impl/clitools.py
+++ b/plainbox/plainbox/impl/clitools.py
@@ -36,6 +36,7 @@ import pdb
import sys
from plainbox.impl.logging import adjust_logging
+from plainbox.impl._argparse import LegacyHelpFormatter
logger = logging.getLogger("plainbox.clitools")
@@ -324,7 +325,9 @@ class ToolBase(metaclass=abc.ABCMeta):
:returns:
argparse.ArgumentParser instance.
"""
- parser = argparse.ArgumentParser(prog=self.get_exec_name())
+ parser = argparse.ArgumentParser(
+ prog=self.get_exec_name(),
+ formatter_class=LegacyHelpFormatter)
parser.add_argument(
"--version", action="version", version=self.get_exec_version())
return parser
--
1.8.5.3
