Rework cmdparse.Script API

The API now requires a command argument from signature. Parsing errors
(no command from input) is thrown as a custom exception, and caught by
the outmost possible invocation to emit a message from click.

pipenv/cmdparse.py

@@ -4,22 +4,27 @@ import shlex
 import six
 
 
+class ScriptEmptyError(ValueError):
+    pass
+
+
 class Script(object):
     """Parse a script line (in Pipfile's [scripts] section).
 
     This always works in POSIX mode, even on Windows.
     """
-    def __init__(self, parts):
-        if not parts:
-            raise ValueError('invalid script')
-        self._parts = parts
-
+    def __init__(self, command, args=None):
+        self._parts = [command]
+        if args:
+            self._parts.extend(args)
 
     @classmethod
     def parse(cls, value):
         if isinstance(value, six.string_types):
             value = shlex.split(value)
-        return cls(value)
+        if not value:
+            raise ScriptEmptyError(value)
+        return cls(value[0], value[1:])
 
     def __repr__(self):
         return 'Script({0!r})'.format(self._parts)

pipenv/core.py

@@ -4,7 +4,6 @@ import logging
 import os
 import sys
 import shutil
-import shlex
 import signal
 import time
 import tempfile
@@ -25,6 +24,7 @@ from blindspin import spinner
 from requests.packages import urllib3
 from requests.packages.urllib3.exceptions import InsecureRequestWarning
 
+from .cmdparse import ScriptEmptyError
 from .project import Project
 from .utils import (
     convert_deps_from_pip,
@@ -2195,23 +2195,14 @@ def inline_activate_virtualenv():
         )
 
 
-def do_run_nt(command, args):
-    """Run command by appending space-joined args to it!"""
+def do_run_nt(script):
     import subprocess
-    p = subprocess.Popen(
-        project.build_script(command, args).cmdify(),
-        shell=True, universal_newlines=True,
-    )
+    p = subprocess.Popen(script.cmdify(), shell=True, universal_newlines=True)
     p.communicate()
     sys.exit(p.returncode)
 
 
-def do_run_posix(command, args):
-    """Attempt to run command either pulling from project or interpreting as executable.
-
-    Args are appended to the command in [scripts] section of project if found.
-    """
-    script = project.build_script(command, args)
+def do_run_posix(script, command):
     command_path = system_which(script.command)
     if not command_path:
         if project.has_script(command):
@@ -2241,15 +2232,23 @@ def do_run_posix(command, args):
 
 
 def do_run(command, args, three=None, python=False):
+    """Attempt to run command either pulling from project or interpreting as executable.
+
+    Args are appended to the command in [scripts] section of project if found.
+    """
     # Ensure that virtualenv is available.
     ensure_project(three=three, python=python, validate=False)
     load_dot_env()
     # Activate virtualenv under the current interpreter's environment
     inline_activate_virtualenv()
+    try:
+        script = project.build_script(command, args)
+    except ScriptEmptyError:
+        click.echo("Can't run script {0!r}—it's empty?", err=True)
     if os.name == 'nt':
-        do_run_nt(command, args)
+        do_run_nt(script)
     else:
-        do_run_posix(command, args)
+        do_run_posix(script, command=command)
 
 
 def do_check(three=None, python=False, system=False, unused=False, args=None):

pipenv/project.py

@@ -399,9 +399,7 @@ class Project(object):
         try:
             script = Script.parse(self.parsed_pipfile['scripts'][name])
         except KeyError:
-            script = Script([name])
-        except ValueError:
-            raise ValueError('invalid script entry {0!r}'.format(name))
+            script = Script(name)
         if extra_args:
             script.extend(extra_args)
         return script

tests/test_cmdparse.py

@@ -1,8 +1,7 @@
-import textwrap
-
-from pipenv.cmdparse import Script
 import pytest
 
+from pipenv.cmdparse import Script, ScriptEmptyError
+
 
 @pytest.mark.run
 @pytest.mark.script
@@ -12,9 +11,17 @@ def test_parse():
     assert script.args == ['-c', "print('hello')"], script
 
 
+@pytest.mark.run
+@pytest.mark.script
+def test_parse_error():
+    with pytest.raises(ScriptEmptyError) as e:
+        Script.parse('')
+    assert str(e.value) == "[]"
+
+
 @pytest.mark.run
 def test_extend():
-    script = Script.parse(['python', '-c', "print('hello')"])
+    script = Script('python', ['-c', "print('hello')"])
     script.extend(['--verbose'])
     assert script.command == 'python'
     assert script.args == ['-c', "print('hello')", "--verbose"], script
@@ -23,7 +30,7 @@ def test_extend():
 @pytest.mark.run
 @pytest.mark.script
 def test_cmdify():
-    script = Script.parse(['python', '-c', "print('hello')"])
+    script = Script('python', ['-c', "print('hello')"])
     cmd = script.cmdify()
     assert cmd == '"python" "-c" "print(\'hello\')"', script