Bug#907249: qml-module-qtwebview: "No WebView plug-in found!" when -dev packages are not installed

[Juhani Numminen <juhaninumminen0@gmail.com>]

Package: qml-module-qtwebview
Version: 5.11.1-2
Severity: grave
Justification: renders package unusable

Dear maintainer,

I am trying out QtWebView in QML with a small test file that
is attached to this mail. After running the following command,
a window with completely white content pops up. I am expecting
to see the Debian website instead.

    juhani@computer:~$ qmlscene webviewtest.qml
    No WebView plug-in found!
    ^C

Installing the libqt5webview5-dev package.

    juhani@computer:~$ sudo apt install -y libqt5webview5-dev 
    Reading package lists... Done
    Building dependency tree       
    Reading state information... Done
    The following additional packages will be installed:
      libqt5quicktest5 qtdeclarative5-dev qtdeclarative5-dev-tools
    The following NEW packages will be installed:
      libqt5quicktest5 libqt5webview5-dev qtdeclarative5-dev
      qtdeclarative5-dev-tools
    0 upgraded, 4 newly installed, 0 to remove and 31 not upgraded.
    Need to get 0 B/752 kB of archives.
    After this operation, 4784 kB of additional disk space will be used.
    Selecting previously unselected package libqt5quicktest5:amd64.
    (Reading database ... 359884 files and directories currently installed.)
    Preparing to unpack .../libqt5quicktest5_5.11.1-4_amd64.deb ...
    Unpacking libqt5quicktest5:amd64 (5.11.1-4) ...
    Selecting previously unselected package qtdeclarative5-dev-tools.
    Preparing to unpack .../qtdeclarative5-dev-tools_5.11.1-4_amd64.deb ...
    Unpacking qtdeclarative5-dev-tools (5.11.1-4) ...
    Selecting previously unselected package qtdeclarative5-dev:amd64.
    Preparing to unpack .../qtdeclarative5-dev_5.11.1-4_amd64.deb ...
    Unpacking qtdeclarative5-dev:amd64 (5.11.1-4) ...
    Selecting previously unselected package libqt5webview5-dev:amd64.
    Preparing to unpack .../libqt5webview5-dev_5.11.1-2_amd64.deb ...
    Unpacking libqt5webview5-dev:amd64 (5.11.1-2) ...
    Setting up libqt5quicktest5:amd64 (5.11.1-4) ...
    Processing triggers for libc-bin (2.27-5) ...
    Setting up qtdeclarative5-dev-tools (5.11.1-4) ...
    Setting up qtdeclarative5-dev:amd64 (5.11.1-4) ...
    Setting up libqt5webview5-dev:amd64 (5.11.1-2) ...

Now that those packages are installed, a window pops up and this time
it's correctly showing the Debian.org website. Also, a cert error is
printed out in the console.

    juhani@computer:~$ qmlscene webviewtest.qml
    [5881:5903:0825/135426.420134:ERROR:nss_util.cc(727)] After loading Root Certs, loaded==false: NSS error code: -8018


Cheers,
Juhani

-- System Information:
Debian Release: buster/sid
  APT prefers testing
  APT policy: (990, 'testing')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.17.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=fi_FI.UTF-8, LC_CTYPE=fi_FI.UTF-8 (charmap=UTF-8), LANGUAGE=fi_FI.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages qml-module-qtwebview depends on:
ii  libc6           2.27-5
ii  libqt5core5a    5.11.1+dfsg-6
ii  libqt5qml5      5.11.1-4
ii  libqt5quick5    5.11.1-4
ii  libqt5webview5  5.11.1-2
ii  libstdc++6      8.2.0-4

qml-module-qtwebview recommends no packages.

qml-module-qtwebview suggests no packages.

-- no debconf information

import QtWebView 1.1

WebView {
    url: "https://www.debian.org/";
}