Fix passing --basetemp to subprocesses with pytest 5.4

[blueyed]

Fixes #510.
Ref: pytest-dev/pytest#6767

Also uses --basetemp with -p no:tmpdir as a good side effect
(ref: #22).

Current failure with py27 due to 4.6.x missing pytest-dev/pytest@3e669a262 (pytest-dev/pytest#6870).

[blueyed]

Failures with pytestmaster are unrelated (due to pytest-dev/pytest#6981).

[RonnyPfannschmidt]

how does this handle missing basetmp parameters - at first glance i would guess, that each process gets its own basetemp if done this way,

in addition the tempoary folder of the workers would be distinct from the directory of the managing process

for sanity this needs at least share the same root folder

[blueyed]

Not sure what you mean, but I've added more tests.

[RonnyPfannschmidt]

The standard mode of operation as users observe does not pass the basetmp valve

As such it seems that und normal operation workers will not share a common basetmp unless you hoist the basetmp variable out of the loop

And there will still be a number of potential issues wrt creating tmpdir in the main process

[blueyed]

The previous self.config._tmpdirhandler should be the same as TempPathFactory.from_config(self.config) (except for that it uses the newer API), no?

The only change / improvement is that it now also works with -p no:tmpdir (a corner case), that previously would silently not use it / skip it.

[RonnyPfannschmidt]

@blueyed you create a new instance each loop, and each instance will make a own numbered tmpdir at the getbasetemp time ...

[blueyed]

Not sure what "loop" you are referring to - I've added one more explicit test, which is the same with xdist master and pytest 5.3.x.

[RonnyPfannschmidt]

with this i currently get

$ rm -rf show
$ mkdir show
$ tree show
show

0 directories, 0 files
$ TMPDIR=./show pytest -n3 testing/test_slavemanage.py 
============================================================================================================ test session starts =============================================================================================================
platform linux -- Python 3.7.6, pytest-5.4.1, py-1.8.1, pluggy-0.13.1
rootdir: /home/rpfannsc/Projects/pytest-dev/pytest-xdist, inifile: tox.ini
plugins: forked-1.1.3, xdist-1.31.1.dev14+g9bc2a95
gw0 [14] / gw1 [14] / gw2 [14]
........xs....                                                                                                                                                                                                                         [100%]
========================================================================================================== short test summary info ===========================================================================================================
SKIPPED [1] /home/rpfannsc/Projects/pytest-dev/pytest-xdist/.env/lib/python3.7/site-packages/_pytest/config/__init__.py:1165: no 'gspecs' option found
XFAIL testing/test_slavemanage.py::TestNodeManager::test_rsync_roots_no_roots
  reason: [NOTRUN] 
================================================================================================== 12 passed, 1 skipped, 1 xfailed in 0.58s ==================================================================================================
$ tree -L 3 show 
show
└── pytest-of-rpfannsc
    ├── pytest-0
    │   └── popen-gw0
    ├── pytest-1
    │   └── popen-gw1
    ├── pytest-2
    │   └── popen-gw2
    └── pytest-current -> /home/rpfannsc/Projects/pytest-dev/pytest-xdist/show/pytest-of-rpfannsc/pytest-2

8 directories, 0 files

[blueyed]

Ok, not worth/easy fixing it in xdist then probably: it could use a single basetemp itself (e.g. via pytest_session_start), but let's keep it in pytest then.