Progress bar restarts from zero after copying files

[Matthew Paul Thomas]

Ubuntu Natty alpha 3
Ubuntu 12.10

When the installer is "Copying files", the installation progress bar fills up completely. When the copying has finished, the progress bar restarts from zero. This makes it much less useful, as it raises the possibility that the progress bar will restart from zero again some unknown number of times.

This was verified in usability testing of the Ubuntu 12.10 installer: three of three participants were surprised that the progress bar restarted from zero. For example: "The installation process is nearly finished, about 75%. Installing system? I’m actually taken to a new thing, I didn’t expect that. It will be nice to tell me the process. I don’t know how many stages, very frustrating, as I thought it was done. Then something else shows up."

Instead, the installation steps should be allocated estimated fractions of the progress bar so that it fills only once for the entire installation.

[Evan (ev)]

This is complicated by a number of things, chief among them debconf's inflexibility with respect to nested progress and the handoff between the core file copy phase (install.py) and the subsequent configuration phase (plugininstall.py).

[Matthew Nuzum (newz)]

How about giving the user a hint of how many times the progress bar will restart then? It's not ideal but it's better.

70% complete of step 1 of 2
[############ ]

[Matthew Paul Thomas (mpt)]

Milestoned after discussion with Evan.

The proper solution is apparently to teach debconf that its progress value is sometimes only for a subtask of a larger task.

A hack solution would be:
- during the first stage, take 0% and add half of the debconf progress value
- during the second stage, take 50% and add half of the debconf progress value.

[Dimitri John Ledkov (xnox)]

I can see that nested progress bar support was introduced in bug 530027.

To me the progress bar has several restarts:
- partitioning resets it back to 0 multiple times
- copying files stage
- "the rest" aka plugininstall

There are possibly additional progress bars that could be launched.

Looking at the logs it's hard to see which progress bars are nested and which are not.

My idea is to take typical install, look at the times and approximately spit the progress bar to get both even and approximately smooth progress bar. It will go through faster & slower sections, but should be ok.

[Dimitri John Ledkov (xnox)]

I have a partial solution for this.

[Colin Watson (cjwatson)]

This bug is mostly full of misinformation; the PROGRESS REGION extension has existed in ubiquity since before it was even called ubiquity. I suspect something is just breaking the protocol stream slightly.