Allow {posargs} in setenv

Fixes #1695

Author: jayvdb

CONTRIBUTORS

@@ -48,6 +48,7 @@ Jake Windle
 Jannis Leidel
 Joachim Brandon LeBlanc
 Johannes Christ
+John Mark Vandenberg
 Jon Dufresne
 Josh Smeaton
 Josh Snyder

docs/changelog/1695.feature.rst

@@ -0,0 +1 @@
+Allow {posargs} in setenv. - by :user:`jayvdb`

src/tox/config/__init__.py

@@ -1559,7 +1559,15 @@ def __repr__(self):
 
 
 class SectionReader:
-    def __init__(self, section_name, cfgparser, fallbacksections=None, factors=(), prefix=None):
+    def __init__(
+        self,
+        section_name,
+        cfgparser,
+        fallbacksections=None,
+        factors=(),
+        prefix=None,
+        posargs="",
+    ):
         if prefix is None:
             self.section_name = section_name
         else:
@@ -1570,6 +1578,7 @@ def __init__(self, section_name, cfgparser, fallbacksections=None, factors=(), p
         self._subs = {}
         self._subststack = []
         self._setenv = None
+        self.posargs = posargs
 
     def get_environ_value(self, name):
         if self._setenv is None:
@@ -1695,6 +1704,17 @@ def getstring(self, name, default=None, replace=True, crossonly=False, no_fallba
         x = self._replace_if_needed(x, name, replace, crossonly)
         return x
 
+    def getposargs(self, default=None):
+        if self.posargs:
+            posargs = self.posargs
+            if sys.platform.startswith("win"):
+                posargs_string = list2cmdline([x for x in posargs if x])
+            else:
+                posargs_string = " ".join([shlex_quote(x) for x in posargs if x])
+            return posargs_string
+        else:
+            return default or ""
+
     def _replace_if_needed(self, x, name, replace, crossonly):
         if replace and x and hasattr(x, "replace"):
             x = self._replace(x, name=name, crossonly=crossonly)
@@ -1781,6 +1801,9 @@ def _replace_match(self, match):
         if not any(g.values()):
             return os.pathsep
 
+        if sub_value == "posargs":
+            return self.reader.getposargs(match.group("default_value"))
+
         try:
             sub_type = g["sub_type"]
         except KeyError:
@@ -1794,6 +1817,8 @@ def _replace_match(self, match):
             if is_interactive():
                 return match.group("substitution_value")
             return match.group("default_value")
+        if sub_type == "posargs":
+            return self.reader.getposargs(match.group("substitution_value"))
         if sub_type is not None:
             raise tox.exception.ConfigError(
                 "No support for the {} substitution type".format(sub_type),
@@ -1887,28 +1912,17 @@ def getargvlist(cls, reader, value, replace=True):
 
     @classmethod
     def processcommand(cls, reader, command, replace=True):
-        posargs = getattr(reader, "posargs", "")
-        if sys.platform.startswith("win"):
-            posargs_string = list2cmdline([x for x in posargs if x])
-        else:
-            posargs_string = " ".join([shlex_quote(x) for x in posargs if x])
-
         # Iterate through each word of the command substituting as
         # appropriate to construct the new command string. This
         # string is then broken up into exec argv components using
         # shlex.
         if replace:
             newcommand = ""
             for word in CommandParser(command).words():
-                if word == "{posargs}" or word == "[]":
-                    newcommand += posargs_string
+                if word == "[]":
+                    newcommand += reader.getposargs()
                     continue
-                elif word.startswith("{posargs:") and word.endswith("}"):
-                    if posargs:
-                        newcommand += posargs_string
-                        continue
-                    else:
-                        word = word[9:-1]
+
                 new_arg = ""
                 new_word = reader._replace(word)
                 new_word = reader._replace(new_word)

tests/unit/config/test_config.py

@@ -441,6 +441,21 @@ def test_command_env_substitution(self, newconfig):
         assert envconfig.commands == [["ls", "testvalue"]]
         assert envconfig.setenv["TEST"] == "testvalue"
 
+    def test_command_env_substitution_posargs(self, newconfig):
+        """Ensure {posargs} values are substituted correctly."""
+        config = newconfig(
+            """
+           [testenv:py27]
+           setenv =
+             TEST={posargs:default}
+           commands =
+             ls {env:TEST}
+        """,
+        )
+        envconfig = config.envconfigs["py27"]
+        assert envconfig.commands == [["ls", "default"]]
+        assert envconfig.setenv["TEST"] == "default"
+
     def test_command_env_substitution_global(self, newconfig):
         """Ensure referenced {env:key:default} values are substituted correctly."""
         config = newconfig(