install/58061: sysinst partitioning duplicates first partition values to the manually added second partition

[vezhlys%gmail.com@localhost]

>Number:         58061
>Category:       install
>Synopsis:       sysinst partitioning duplicates first partition values to the manually added second partition
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    install-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Mar 21 21:15:00 +0000 2024
>Originator:     Andrius V
>Release:        NetBSD 10 RC6 amd64
>Organization:
>Environment:
>Description:
Hi,

Today I was installing NetBSD 10 RC6 on my new amd64 system and noticed and erratic behaviour with the partitioning gpt partitions if "Use default partition sizes" option was selected. If the first (root) partition is resized (which initially takes full available space before "swap") and second one is added, after clicking OK a and b partitions will show exactly same values for partition starting point, size, fs type. Flags and mounting point may differ. Trying to change first or second again, will likely affect both, maybe except flags (which may depend on the flags selected). Adding third one will have the same issue as well.


>How-To-Repeat:
Steps to reproduce:
Install NetBSD to hard disk
Shall we continue -> Yes
Available disks -> wd0
Choose Guid Partition Table (GPT) for partitioning scheme
What would you like to do? -> b: Use default partition sizes
Resize partition a too a smaller size -> OK
Add a partition -> should show correct start value and size after partition a -> click OK
Partition a and b will show same values in the partition table for at least start/end/size and fs type, flags and mount point may differ but changing those will behave erratically if changed.
Trying to edit partition b still will show partition a values and editing it will edit "both".

Adding "third" partition will have similar issue.
>Fix: