Allow backslashing curly braces to prevent expansion

e.g.: commands=echo \{posargs\} = {posargs}

1 files changed, 3 insertions, 3 deletions

diff --git a/tox/_config.py b/tox/_config.py
index 6006fa9..4d54924 100644
--- a/tox/_config.py
+++ b/tox/_config.py
@@ -451,8 +451,8 @@ class IndexServerConfig:
         self.url = url
 
 RE_ITEM_REF = re.compile(
-    '''
-    [{]
+    r'''
+    (?<!\\)[{]
     (?:(?P<sub_type>[^[:{}]+):)?    # optional sub_type for special rules
     (?P<substitution_value>[^{}]*)  # substitution key
     [}]
@@ -686,7 +686,7 @@ class CommandParser(object):
         def word_has_ended():
             return ((cur_char in string.whitespace and ps.word and
                ps.word[-1] not in string.whitespace) or
-              (cur_char == '{' and ps.depth == 0) or
+              (cur_char == '{' and ps.depth == 0 and not ps.word.endswith('\\')) or
               (ps.depth == 0 and ps.word and ps.word[-1] == '}') or
               (cur_char not in string.whitespace and ps.word and
                ps.word.strip() == ''))