"sudo unattended-upgrade --dry-run -d" download packages?

[photonxp]

I've got the answer. "unattended-upgrade --dry-run" do download packages.

unattended-upgrades --help
--dry-run Simulation, download but do not install
====================================
Just run the command "sudo unattended-upgrade --dry-run -d" and found out it downloaded packages from the Ubuntu mirror site.
Is that the right behaviour?


man unattended-upgrade

--dry-run
Just simulate installing updates, do not actually do it

I also tried

sudo apt-get upgrade --dry-run
which didn't download packages at all.

Could anyone do the favour to reduplicate my procedure to verify or negate the result?
Right now I don't have any other Ubuntu pc or virtual machine available.
You'd better backup your system and data before you try.

Here is my procedure:


lsb_release -a

No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.1 LTS
Release: 16.04
Codename: xenial


uname -a

Linux ub 4.4.0-98-generic #121-Ubuntu SMP Tue Oct 10 14:24:03 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux



sudo unattended-upgrade --dry-run -d


... ...
wget
wpasupplicant
xserver-common
xserver-xorg-core
xul-ext-ubufox
Get:1 http://mirrors.duke.edu/ubuntu xenial-updates/main amd64 libreoffice-core amd64 1:5.1.6~rc2-0ubuntu1~xenial2 [28.2 MB]
54% [1 libreoffice-core 18.6 MB/28.2 MB 66%]


Ctrl + C
to Interrupt the process:


... ...
wget
wpasupplicant
xserver-common
xserver-xorg-core
xul-ext-ubufox
Get:1 http://mirrors.duke.edu/ubuntu xenial-updates/main amd64 libreoffice-core amd64 1:5.1.6~rc2-0ubuntu1~xenial2 [28.2 MB]
54% [1 libreoffice-core 18.8 MB/28.2 MB 66%] 16.5 kB/s 2h 4min 38s^CError in function stop
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/apt/progress/text.py", line 233, in stop
def stop(self):
KeyboardInterrupt
Traceback (most recent call last):
File "/usr/bin/unattended-upgrade", line 1468, in <module>
main(options)
File "/usr/bin/unattended-upgrade", line 1243, in main
res = fetcher.run()
SystemError: E:Method http has died unexpectedly!, E:Sub-process http returned an error code (100)

Is this download behaviour a bug or not?

[photonxp]

Upgrade packages of apt apt-utils libapt-pkg5.0 unattended-upgrades,
then "sudo unattended-upgrade --dry-run -d"

Still download packages from Ubuntu mirror site.
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Problem Solved.