Cancelling operations is allowed when allow_cancel is FALSE

[iainlane]

This is related to this gnome-software bug.

I tried to reproduce it with packagekitd --verbose running, and got the following output on the terminal:

16:02:17	PackageKit          emitting allow-cancel 0
16:02:17	PackageKit          opened logind fd 42
16:02:17	PackageKit          1 transactions in list, 1 committed but not finished
PARENT process running...
16:02:19	PackageKit          emit package installing, libphobos2-ldc72;1:1.2.0-1;amd64;ubuntu-artful-universe, LLVM D Compiler - Phobos2 Standard library, shared objects
16:02:19	PackageKit          emitting item-progress libphobos2-ldc72;1:1.2.0-1;amd64;ubuntu-artful-universe, install: 0
16:02:19	PackageKit          emit package preparing, libphobos2-ldc72;1:1.2.0-1;amd64;ubuntu-artful-universe, LLVM D Compiler - Phobos2 Standard library, shared objects
16:02:19	PackageKit          emitting item-progress libphobos2-ldc72;1:1.2.0-1;amd64;ubuntu-artful-universe, setup: 25
16:02:19	PackageKit          emit package decompressing, libphobos2-ldc72;1:1.2.0-1;amd64;ubuntu-artful-universe, LLVM D Compiler - Phobos2 Standard library, shared objects
16:02:19	PackageKit          emitting item-progress libphobos2-ldc72;1:1.2.0-1;amd64;ubuntu-artful-universe, install: 50
16:02:19	PackageKit          emit package preparing, libphobos2-ldc72;1:1.2.0-1;amd64;ubuntu-artful-universe, LLVM D Compiler - Phobos2 Standard library, shared objects
16:02:19	PackageKit          emitting item-progress libphobos2-ldc72;1:1.2.0-1;amd64;ubuntu-artful-universe, setup: 75
16:02:19	PackageKit          emit package finished, libphobos2-ldc72;1:1.2.0-1;amd64;ubuntu-artful-universe, LLVM D Compiler - Phobos2 Standard library, shared objects
16:02:19	PackageKit          emit package installing, libgtkd-3-0;3.6.5-2ubuntu1;amd64;ubuntu-artful-universe, GTK+ graphical user interface library - D bindings
16:02:19	PackageKit          emitting item-progress libgtkd-3-0;3.6.5-2ubuntu1;amd64;ubuntu-artful-universe, install: 0
16:02:19	PackageKit          emit package preparing, libgtkd-3-0;3.6.5-2ubuntu1;amd64;ubuntu-artful-universe, GTK+ graphical user interface library - D bindings
16:02:19	PackageKit          emitting item-progress libgtkd-3-0;3.6.5-2ubuntu1;amd64;ubuntu-artful-universe, setup: 25
16:02:20	PackageKit          Cancel method called on /66_aecbccbd
16:02:20	PackageKit          same sender, no need to check uid
Parent finished...
16:02:20	PackageKit          emitting allow-cancel 1
16:02:20	PackageKit          closed logind fd 42
16:02:20	PackageKit          1 transactions in list, 1 committed but not finished
16:02:20	PackageKit          internal error: failed, but no error code: cancelled
16:02:20	PackageKit          backend was running for 4428 ms
16:02:20	PackageKit          emitting finished 'cancelled', 4428
16:02:20	PackageKit          internal error: failed, but no error code: cancelled
16:02:20	PackageKit          transaction now finished
16:02:20	PackageKit          1 transactions in list, 0 committed but not finished
16:02:25	PackageKit          transaction /66_aecbccbd completed, removing
16:02:25	PackageKit          emitting destroy /66_aecbccbd

So the backend said we couldn't cancel, yet when the cancellable was cancelled, we went ahead and stopped the operation anyway.

I think there's probably a UI bug in gnome-software too that it should have respected allow_cancel being set to FALSE and hid the button in that case.

[iainlane]

@ximion

[dantti]

@hughsie shouldn't the pk-backend method check allow_cancel before dispatching to the backend?

[hughsie]

That, and also the GNOME UI should have the correct button sensitivity set...

[dantti]

Yup, otherwise, it would still be cancelable via DBus, I could fix aptcc but fixing in pk-backend means no other backend might get hit by this.. tho I'm not sure in a threaded backend this would be enough.