command: fix handling of env-vars passed to plumbum Commands; support…

… new with_cwd

- don't use the non-threadsafe and session-dependent .env() context manager
- sync popen support for 'env' param in all machine impls: local/ssh/paramiko
- add .with_cwd() to complement .with_env()

plumbum/commands/base.py

@@ -98,11 +98,17 @@ def __call__(self, *args, **kwargs):
     def _get_encoding(self):
         raise NotImplementedError()
 
-    def with_env(self, **envvars):
+    def with_env(self, **env):
         """Returns a BoundEnvCommand with the given environment variables"""
-        if not envvars:
+        if not env:
             return self
-        return BoundEnvCommand(self, envvars)
+        return BoundEnvCommand(self, env=env)
+
+    def with_cwd(self, path):
+        """Returns a BoundEnvCommand with the specified working directory"""
+        if not path:
+            return self
+        return BoundEnvCommand(self, cwd=path)
 
     setenv = with_env
 
@@ -313,14 +319,15 @@ def popen(self, args=(), **kwargs):
 
 
 class BoundEnvCommand(BaseCommand):
-    __slots__ = ("cmd", "envvars")
+    __slots__ = ("cmd", "env", "cwd")
 
-    def __init__(self, cmd, envvars):
+    def __init__(self, cmd, env={}, cwd=None):
         self.cmd = cmd
-        self.envvars = envvars
+        self.env = env
+        self.cwd = cmd.cwd if cwd is None else cwd
 
     def __repr__(self):
-        return "BoundEnvCommand(%r, %r)" % (self.cmd, self.envvars)
+        return "BoundEnvCommand(%r, %r)" % (self.cmd, self.env)
 
     def _get_encoding(self):
         return self.cmd._get_encoding()
@@ -332,9 +339,12 @@ def formulate(self, level=0, args=()):
     def machine(self):
         return self.cmd.machine
 
-    def popen(self, args=(), **kwargs):
-        with self.machine.env(**self.envvars):
-            return self.cmd.popen(args, **kwargs)
+    def popen(self, args=(), cwd=None, env={}, **kwargs):
+        return self.cmd.popen(
+            args,
+            cwd=self.cwd if cwd is None else cwd,
+            env=dict(self.env, **env),
+            **kwargs)
 
 
 class Pipeline(BaseCommand):

plumbum/machines/local.py

@@ -291,10 +291,15 @@ def preexec_fn(prev_fn=kwargs.get("preexec_fn", lambda: None)):
 
         if cwd is None:
             cwd = self.cwd
-        if env is None:
-            env = self.env
-        if isinstance(env, BaseEnv):
-            env = env.getdict()
+
+        envs = [self.env, env]
+        env = {}
+        for _env in envs:
+            if not _env:
+                continue
+            if isinstance(_env, BaseEnv):
+                _env = _env.getdict()
+            env.update(_env)
 
         if self._as_user_stack:
             argv, executable = self._as_user_stack[-1](argv)

plumbum/machines/paramiko_machine.py

@@ -313,10 +313,13 @@ def popen(self,
               stdout=None,
               stderr=None,
               new_session=False,
+              env=None,
               cwd=None):
         # new_session is ignored for ParamikoMachine
         argv = []
         envdelta = self.env.getdelta()
+        if env:
+            envdelta.update(env)
         argv.extend(["cd", str(cwd or self.cwd), "&&"])
         if envdelta:
             argv.append("env")

plumbum/machines/ssh_machine.py

@@ -127,13 +127,20 @@ def __str__(self):
         return "ssh://%s" % (self._fqhost, )
 
     @_setdoc(BaseRemoteMachine)
-    def popen(self, args, ssh_opts=(), **kwargs):
+    def popen(self, args, ssh_opts=(), env=None, cwd=None, **kwargs):
         cmdline = []
         cmdline.extend(ssh_opts)
         cmdline.append(self._fqhost)
-        if args and hasattr(self, "env"):
-            envdelta = self.env.getdelta()
-            cmdline.extend(["cd", str(self.cwd), "&&"])
+        if args:
+            envdelta = {}
+            if hasattr(self, "env"):
+                envdelta.update(self.env.getdelta())
+            if env:
+                envdelta.update(env)
+            if cwd is None:
+                cwd = getattr(self, "cwd", None)
+            if cwd:
+                cmdline.extend(["cd", str(cwd), "&&"])
             if envdelta:
                 cmdline.append("env")
                 cmdline.extend("%s=%s" % (k, shquote(v)) for k, v in envdelta.items())

tests/test_local.py

@@ -858,6 +858,8 @@ def test_bound_env(self):
             assert printenv.with_env(FOO = "sea", BAR = "world")("FOO") == "sea\n"
             assert printenv("FOO") == "hello\n"
 
+        assert local.cmd.pwd.with_cwd("/")() == "/\n"
+
     def test_nesting_lists_as_argv(self):
         from plumbum.cmd import ls
         c = ls["-l", ["-a", "*.py"]]

tests/test_remote.py

@@ -375,6 +375,8 @@ def test_bound_env(self):
                 assert printenv.with_env(FOO = "sea", BAR = "world")("FOO") == "sea\n"
                 assert printenv.with_env(FOO = "sea", BAR = "world")("BAR") == "world\n"
 
+            assert rem.cmd.pwd.with_cwd("/")() == "/\n"
+
     @pytest.mark.skipif('useradd' not in local,
             reason = "System does not have useradd (Mac?)")
     def test_sshpass(self):