escaping curly braces in a tox command doesn't work

I was trying to delete a few specific files using the "find" command, but couldn't get tox to ignore the required curly braces in the command:

py26 runtests: commands[2] | find /Users/.../dev/.../.tox/py26 -name *.so -exec rm \{\} +
WARNING:test command found but not installed in testenv
  cmd: /usr/bin/find
  env: /Users/.../dev/.../.tox/py26
Maybe forgot to specify a dependency?
find: -exec: no terminating ";" or "+"
ERROR: InvocationError: '/usr/bin/find /Users/.../dev/.../.tox/py26 -name *.so -exec rm \\{\\} +'

Having "{}" in the tox command breaks since tox looks for a variable named "" in the config. The above is the result of attempting to escape the curly braces with back-slashes, as per the documentation: You can escape curly braces with the \ character if you need them, ...

My environment:

• OSX 10.8
• Python 3.4.2 (installed via pyenv)
• tox 1.8.1 (installed via pip)

Encountered this on tox 2.1.1 on ubuntu 14.04 python 2.7.6.

Made use of find -exec impossible since the slashes were leaked through. Managed to work around with -execdir, since that doesn't require the brackets.

I managed to find a "better" workaround by invoking bash in the tox.ini

bash -c \'find {envsitepackagesdir} -name my_directory_criteria -type d -print0 | xargs -0 django-admin.py test [] \'

It looks like this feature was introduced in https://bitbucket.org/hpk42/tox/commits/9d7345ef4b2be4f12a30a887fcda30c7b268c245 , and tests in https://bitbucket.org/hpk42/tox/commits/0c8a958f574b9d25eb16343e318cf88495087bd5

However I also cant find any version of tox, or tox incantation, where it works as explained in the documentation.

Before that commit in 1.8.x, \{..\} would produce

Traceback (most recent call last):
  File "/usr/bin/tox", line 9, in <module>
    load_entry_point('tox==1.8.0', 'console_scripts', 'tox')()
  File "/usr/lib/python2.7/site-packages/tox/_cmdline.py", line 25, in main
    config = parseconfig(args, 'tox')
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 42, in parseconfig
    parseini(config, inipath)
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 296, in __init__
    self._makeenvconfig(name, section, reader._subs, config)
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 359, in _makeenvconfig
    vc.commands = reader.getargvlist(section, "commands")
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 552, in getargvlist
    commandlist.append(self._processcommand(current_command))
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 581, in _processcommand
    new_word = self._replace(word)
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 730, in _replace
    return RE_ITEM_REF.sub(self._replace_match, x)
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 726, in _replace_match
    return handler(match)
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 697, in _replace_substitution
    val = self._substitute_from_other_section(sub_key)
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 686, in _substitute_from_other_section
    return self._replace(x)
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 730, in _replace
    return RE_ITEM_REF.sub(self._replace_match, x)
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 726, in _replace_match
    return handler(match)
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 697, in _replace_substitution
    val = self._substitute_from_other_section(sub_key)
  File "/usr/lib/python2.7/site-packages/tox/_config.py", line 691, in _substitute_from_other_section
    "substitution key %r not found" % key)
tox.ConfigError: ConfigError: substitution key '\\' not found

So it looks like it was a partial fix, avoiding the config layer claiming it as substitution, but the un-quoting part of the fix wasnt done.

https://bitbucket.org/hpk42/tox/pull-requests/185 fixes this for me

The problem will be how to fix this, without breaking anyone who relies on the current approach. Marc Abramowitz, do you depend on the current functionality as you implemented it?

A reasonable way to avoid this being a breaking change is to use {{..}} as the way to add literals, as that is the same syntax as str.format, and I am guessing that '{foo}' is an illegal variable name (or at least it is an improbable and silly name to be in use as a variable name.).

using {{..}} would also be a breaking change, as that is legal syntax; see https://bitbucket.org/hpk42/tox/pull-requests/186

I don't depend on the current functionality.

add changelog entry for latest PR merge: fix issue212: allow escaping curly brace chars "{" and "}" if you need the chars "{" and "}" to appear in your commands or other ini values. Thanks John Vandenberg.

→ <<cset b609deef30f3>>

This issue has been moved to GitHub: https://github.com/tox-dev/tox/issues/212