accessing the folder using a webmail indicates the only new message is the one named "new webP image plugin..."

The crash is back this morning (coincidence (?): still in my k.c.d folder)

Is there anything I could provide ?

#9  0x00007fe10afa629d in MessageList::Core::ModelPrivate::viewItemJobStepInternalForJobPass1Fill (this=0x1bb78f0, job=0x4c7b5c0, tStart=...) at /kde/src/pim/kdepim/messagelist/core/model.cpp:2798
        it = {i = 0x73835a8}
---Type <return> to continue, or q <return> to quit---
        end = {i = 0x73835b0}
        lImperfectlyThreaded = {{p = {static shared_null = {ref = {_q_value = 34525}, alloc = 0, begin = 0, end = 0, sharable = 1, array = {0x0}}, d = 0x7383590}, d = 0x7383590}}
        needsImmediateReAttach = false
        pParent = 0x50a7df0
        md5 = {static shared_null = {ref = {_q_value = 1}, alloc = 0, size = 0, data = 0x405f18 <QByteArray::shared_null+24> "", array = ""}, static shared_empty = {ref = {_q_value = 308}, alloc = 0, size = 0, data = 
    0x7fe10f281778 <QByteArray::shared_empty+24> "", array = ""}, d = 0x7383dc0}
        bUseReceiver = false
        curIndex = 1233
        mi = 0x7383f60
        __PRETTY_FUNCTION__ = "MessageList::Core::ModelPrivate::ViewItemJobResult MessageList::Core::ModelPrivate::viewItemJobStepInternalForJobPass1Fill(MessageList::Core::ViewItemJob*, const QTime&)"
        elapsed = 53
        endIndex = 8338
#10 0x00007fe10afa7cff in MessageList::Core::ModelPrivate::viewItemJobStepInternalForJob (this=0x1bb78f0, job=0x4c7b5c0, tStart=...) at /kde/src/pim/kdepim/messagelist/core/model.cpp:3374
        elapsed = 0
        __PRETTY_FUNCTION__ = "MessageList::Core::ModelPrivate::ViewItemJobResult MessageList::Core::ModelPrivate::viewItemJobStepInternalForJob(MessageList::Core::ViewItemJob*, const QTime&)"
#11 0x00007fe10afa8790 in MessageList::Core::ModelPrivate::viewItemJobStepInternal (this=0x1bb78f0) at /kde/src/pim/kdepim/messagelist/core/model.cpp:3761
        job = 0x4c7b5c0
        tStart = {mds = 44756733}
        elapsed = 0
        __PRETTY_FUNCTION__ = "MessageList::Core::ModelPrivate::ViewItemJobResult MessageList::Core::ModelPrivate::viewItemJobStepInternal()"
#12 0x00007fe10afa90e4 in MessageList::Core::ModelPrivate::viewItemJobStep (this=0x1bb78f0) at /kde/src/pim/kdepim/messagelist/core/model.cpp:3947
        currentIndexBeforeStep = {r = 0, c = 0, p = 0x4ed3cb0, m = 0x1908f40}
        currentItemBeforeStep = 0x4ed3cb0
        lockView = true
        __PRETTY_FUNCTION__ = "void MessageList::Core::ModelPrivate::viewItemJobStep()"
        rectBeforeViewItemJobStep = {x1 = 0, y1 = 0, x2 = -1, y2 = -1}
#13 0x00007fe10afab19c in MessageList::Core::Model::qt_static_metacall (_o=0x1908f40, _c=QMetaObject::InvokeMetaMethod, _id=2, _a=0x7fff2ed04c70) at /kde/build/pim/kdepim/messagelist/model.moc:69
        _t = 0x1908f40

Adding "the only person in the universe who knows how modellist works" ©

As it seems to happen with a particular account & folder, more information:

* The filtering is done server side (a zimbra frontend). There are two filters set for this mailing list:
1/ IF the "List-Id" header contains : "kde-core-devel.kde.org" AND the "X-ReviewBoard-URL" header MATCHES "http://git.reviewboard.kde.org", move to "kde/mailing lists/kde-core-devel/review requests" (and stop processing)

2/ IF the "List-Id" header contains : "kde-core-devel.kde.org", move the message into "kde/mailing lists/kde-core-devel"

The crash was only reproduced with this folder afair (I use the same kind of rules for other mailing-lists)

* In KMail settings, Appearance, Message List: Activity by date, threaded and the classic theme are used.

This bug has only been reported for versions before 4.14, which have been unsupported for at least two years now. Can anyone tell if this bug still present?

If noone confirms this bug for a Framework-based version of kmail2 (version 5.0 or later, as part of KDE Applications 15.12 or later), it gets closed in about three months.

Just as announced in my last comment, I close this bug. If you encounter it again in a recent version (at least 5.0 aka 15.08), please open a new one unless it already exists. Thank you for all your input.