Title: PyImport_GetModule() can return partially-initialized module
Type: behavior Stage: resolved
Components: Interpreter Core Versions: Python 3.8, Python 3.7
Status: closed Resolution: fixed
Dependencies: Superseder:
Assigned To: nanjekyejoannah Nosy List: Valentyn Tymofieiev, brett.cannon, eric.snow, nanjekyejoannah, ncoghlan, p-ganssle, pablogsal, pitrou, vstinner
Priority: normal Keywords: patch

Created on 2019-02-08 17:13 by pitrou, last changed 2019-11-19 17:37 by brett.cannon. This issue is now closed.

Pull Requests
URL Status Linked Edit
PR 15057 merged nanjekyejoannah, 2019-07-31 15:51
Messages (5)
msg335097 - (view) Author: Antoine Pitrou (pitrou) * (Python committer) Date: 2019-02-08 17:13
PyImport_GetModule() returns whatever is in sys.modules, even if the module is still importing and therefore only partially initialized.

One possibility is to reuse the optimization already done in PyImport_ImportModuleLevelObject():

        /* Optimization: only call _bootstrap._lock_unlock_module() if
           __spec__._initializing is true.
           NOTE: because of this, initializing must be set *before*
           stuffing the new module in sys.modules.
        spec = _PyObject_GetAttrId(mod, &PyId___spec__);
        if (_PyModuleSpec_IsInitializing(spec)) {
            PyObject *value = _PyObject_CallMethodIdObjArgs(interp->importlib,
                                            &PyId__lock_unlock_module, abs_name,
            if (value == NULL) {
                goto error;

Issue originally mentioned in issue34572.
msg335100 - (view) Author: Eric Snow (eric.snow) * (Python committer) Date: 2019-02-08 17:18
Yeah, that makes sense.
msg351847 - (view) Author: Brett Cannon (brett.cannon) * (Python committer) Date: 2019-09-11 12:47
New changeset 37c22206981f52ae35c28b39f7530f8438afbfdb by Brett Cannon (Joannah Nanjekye) in branch 'master':
bpo-35943: Prevent PyImport_GetModule() from returning a partially-initialized module (GH-15057)
msg356920 - (view) Author: Valentyn Tymofieiev (Valentyn Tymofieiev) Date: 2019-11-18 22:11
Do we plan to backport the change by nanjekyejoannah to 3.7 branch?
msg356980 - (view) Author: Brett Cannon (brett.cannon) * (Python committer) Date: 2019-11-19 17:37
I've assigned this to Joannah to decide if she wants to backport this.
Date User Action Args
2019-11-19 17:37:29brett.cannonsetassignee: nanjekyejoannah

messages: + msg356980
nosy: + nanjekyejoannah
2019-11-18 22:11:12Valentyn Tymofieievsetnosy: + Valentyn Tymofieiev
messages: + msg356920
2019-09-11 12:48:02brett.cannonsetstatus: open -> closed
resolution: fixed
stage: patch review -> resolved
2019-09-11 12:47:42brett.cannonsetmessages: + msg351847
2019-07-31 15:51:07nanjekyejoannahsetkeywords: + patch
stage: needs patch -> patch review
pull_requests: + pull_request14806
2019-02-22 17:27:35pitrousetnosy: + vstinner
2019-02-08 18:56:13p-gansslesetnosy: + p-ganssle
2019-02-08 17:19:40pitrousetnosy: + pablogsal
2019-02-08 17:18:15eric.snowsetmessages: + msg335100
2019-02-08 17:13:37pitroucreate