Question

我有以下代码：

def handle_empty_directories(dir):
    if os.path.exists(dir):
        shouter.shout("%s exists" % dir)
    else:
       shouter.shout("%s doesn't exists" % dir)
    entries = os.listdir(dir)
    if entries == []:
        open(os.path.join(dir, Commiter.hed_file), "w").close()
    else:
        if (len(entries) > 1) and (Commiter.hed_file in entries):
            os.remove(os.path.join(dir, Commiter.hed_file))
        for entry in entries:
            if entry not in Commiter.hed_ignore:
                full_entry = os.path.join(dir, entry)
                if (os.path.isdir(full_entry)):
                    Commiter.handle_empty_directories(full_entry)

有时，即使os.listdir(dir)调用表明存在，对FileNotFoundError的调用也以os.path.exists(dir)失败：

08:57:56 - C:\r2g-wd\sport-6.0.5\SBS\SBS\Light\bin\com\ibm\ArtifactTechnology\ABS\ArtifactBroker exists
Traceback (most recent call last):
  File "migration.py", line 169, in <module>
    migrate()
  File "migration.py", line 80, in migrate
    rtc.acceptchangesintoworkspace(rtc.getchangeentriestoaccept(changeentries, history))
  File "c:\Users\GeoffAlexander\Documents\Nirvana\RTC2Git\git-repositories\rtc2git-migration-tool\rtcFunctions.py", line 304, in acceptchangesintoworkspace
    Commiter.handle_empty_directories(os.getcwd())
  File "c:\Users\GeoffAlexander\Documents\Nirvana\RTC2Git\git-repositories\rtc2git-migration-tool\gitFunctions.py", line 126, in handle_empty_directories
    Commiter.handle_empty_directories(full_entry)
  File "c:\Users\GeoffAlexander\Documents\Nirvana\RTC2Git\git-repositories\rtc2git-migration-tool\gitFunctions.py", line 126, in handle_empty_directories
    Commiter.handle_empty_directories(full_entry)
  File "c:\Users\GeoffAlexander\Documents\Nirvana\RTC2Git\git-repositories\rtc2git-migration-tool\gitFunctions.py", line 126, in handle_empty_directories
    Commiter.handle_empty_directories(full_entry)
  [Previous line repeated 6 more times]
  File "c:\Users\GeoffAlexander\Documents\Nirvana\RTC2Git\git-repositories\rtc2git-migration-tool\gitFunctions.py", line 116, in handle_empty_directories
    entries = os.listdir(dir)
FileNotFoundError: [WinError 3] The system cannot find the path specified: 'C:\\r2g-wd\\sport-6.0.5\\SBS\\SBS\\Light\\bin\\com\\ibm\\ArtifactTechnology\\ABS\\ArtifactBroker'

这怎么可能发生？我在Windows 10上运行64位Python 3.7.2。

Answer 1

这很可能是比赛条件。从测试目录是否存在到对目录进行处理之间存在一段时间，在此期间可以被另一个进程删除。

避免这种情况的通常方法是尝试操作，并为失败做好准备，例如：

try:
  os.listdir(x)
except FileNotFoundError:
  # log and stop here

目录存在时，Python os.listdir失败，并出现FileNotFoundError

1 个答案: