python - 无法使用 python 自动执行 git fetch && git checkout

Question

我已经自动化了 git checkout 用户想要输入的特定分支的过程。我正在使用以下带有子进程的 python 代码来执行此操作，

from bitbucket.bitbucket import Bitbucket
from sys import argv
import subprocess

prompt = '> '

print "Enter the name of branch you need to clone: "
user_branch = raw_input(prompt)

print "You Entered: ",user_branch


print "this will do a git status"
cmd = subprocess.Popen(["git", "status"], stdout=subprocess.PIPE)
output = cmd.communicate()[0]
print output
#for line in output: # output.split("\n"):
if  ("Untracked files:" or "Changes not staged for commit") in  output:
     print "Need to do a Git stash"
     subprocess.Popen(["git", "stash"])
     subprocess.Popen(["git fetch && git checkout"+(user_branch)])
else:
     print "simply do git checkout userbranch"
     subprocess.Popen(["git","pull"])
     subprocess.Popen(["git fetch && git checkout"+(user_branch)])

这会抛出:

Enter the name of branch you need to clone: 
> release_4_0
You Entered:  release_4_0
this will do a git status
On branch master
Your branch is up-to-date with 'origin/master'.

nothing to commit, working directory clean

simply do git checkout userbranch
Traceback (most recent call last):
  File "git_updater.py", line 25, in <module>
    subprocess.Popen(["git fetch && git checkout"+(user_branch)])
  File "/usr/lib/python2.7/subprocess.py", line 710, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1327, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory

我只想输入用户想要 checkout 的分支名称。这有道理吗？

Answer 1

subprocess.Popen(["git fetch && git checkout"+(user_branch)])

应该是

subprocess.Popen("git fetch && git checkout %s"%user_branch,shell=True)

或者你可以做类似的事情

subprocess.Popen(["git", "fetch"]).communicate()
subprocess.Popen(["git", "checkout", user_branch])

问题是，如果参数是一个列表，它需要逗号分隔的文件和参数(我不确定 && 将如何工作)