740             start_new_session = True

   740             start_new_session = True

   741         else:

   741         else:

   742             start_new_session = False

   742             start_new_session = False

   743             ensurestart = True

   743             ensurestart = True

   744 

   744 

   745         try:

   747         try:

   746             if stdin_bytes is None:

   748             if stdin_bytes is None:

   747                 stdin = subprocess.DEVNULL

   749                 stdin = subprocess.DEVNULL

   748             else:

   750             else:

   749                 stdin = pycompat.unnamedtempfile()

   751                 stdin = pycompat.unnamedtempfile()

   768         except Exception:

   770         except Exception:

   769             if record_wait is not None:

   771             if record_wait is not None:

   770                 record_wait(255)

   772                 record_wait(255)

   771             raise

   773             raise

   772         finally:

   774         finally:

   774                 assert not isinstance(stdin, int)

   776                 assert not isinstance(stdin, int)

   775                 stdin.close()

   777                 stdin.close()

   776         if not ensurestart:

   778         if not ensurestart:

   777             # Even though we're not waiting on the child process,

   779             # Even though we're not waiting on the child process,

   778             # we still must call waitpid() on it at some point so

   780             # we still must call waitpid() on it at some point so

   850                         % (cmd, os.strerror(returncode)),

   852                         % (cmd, os.strerror(returncode)),

   851                     )

   853                     )

   852                 return

   854                 return

   853 

   855 

   854         returncode = 255

   856         returncode = 255

   855         try:

   859         try:

   856             if record_wait is None:

   860             if record_wait is None:

   857                 # Start a new session

   861                 # Start a new session

   858                 os.setsid()

   862                 os.setsid()

   859             # connect stdin to devnull to make sure the subprocess can't

   863             # connect stdin to devnull to make sure the subprocess can't

   892         except Exception:

   896         except Exception:

   893             returncode = 255

   897             returncode = 255

   894         finally:

   898         finally:

   895             # mission accomplished, this child needs to exit and not

   899             # mission accomplished, this child needs to exit and not

   896             # continue the hg process here.

   900             # continue the hg process here.

   898             if record_wait is None:

   903             if record_wait is None:

   899                 os._exit(returncode)

   904                 os._exit(returncode)

   900 

   905 

   901     if pycompat.ispy3:

   906     if pycompat.ispy3:

   902         # This branch is more robust, because it avoids running python

   907         # This branch is more robust, because it avoids running python