** Summary changed:
- [FFe] Case-fold the Windows username before sanitization
+ Case-fold the Windows username before sanitization
** Description changed:
- ## FFE ##
-
- NOTE: This only affects Ubuntu on WSL and questing, being an interim
- release, is not publicized as an official release for this platform and
- it's not installable from `wsl.exe --install` command line for example
- (we only "publish" LTSes).
-
The `wsl-setup` script reads the Windows user name and sanitizes it,
dropping invalid characters for a Linux user name, including ASCII upper
case letters. We could case fold the username first and then drop the
invalid ones, making it a bit less surprising. That would still have
some nasty cases we cannot handle in a smart way, like `MartínJoão` being
converted into `martnjoo` but that’s why we prompt for the username, to
let users edit that before actual submission.
While case folding can be done with `tr "[:upper:]" "[:lower:]"` or even
better `awk '{print tolower(0)}'` (awk handles Unicode better), better yet
is to leverage PowerShell because then we're guaranteed to respect the
Windows user locale (a WSL instance could be set up with a different
locale and the case-folding results couldn't match the user's
expectation).
To illustrate how this works:
```bash
j@DESKTOP-551PQ9O:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04.6 LTS
Release: 20.04
Codename: focal
j@DESKTOP-551PQ9O:~$ powershell.exe -Command '$Env:Username'
João
j@DESKTOP-551PQ9O:~$ var="Username"; powershell.exe -NoProfile -Command '& {
[Console]::OutputEncoding = [System.Text.Encoding]::UTF8
$Env:'"${var}"'}'
João
j@DESKTOP-551PQ9O:~$ var="Username.ToLower()"; powershell.exe -NoProfile
-Command '& {
[Console]::OutputEncoding = [System.Text.Encoding]::UTF8
$Env:'"${var}"'}'
joão
```
In the example above the username would be sanitized to: `oo`
but with the changes it would at least be: `joo`
(the 'ã' is still dropped, but it's much easier to add it).
The motivation for this change came from a user named `AdminUser`.
That would originally be sanitized to: `dminser`
but now it becomes: `adminuser`
One must remember that in the end this name is just a suggestion
prefilling a read input. User is free to edit it before hitting enter
and submitting the username to the `adduser` program.
-
- ### Changelog ###
-
- wsl-setup (0.5.11) questing; urgency=medium
-
- * Case-fold the Windows username before sanitization (LP: #2122047)
-
- -- Carlos Nihelton <[email protected]> Thu, 04 Sep 2025 11:08:42
- -0300
-
- ### Build ###
-
- ### Install Logs ###
-
- ### Testing Done ###
** Changed in: wsl-setup (Ubuntu)
Status: Expired => New
** Also affects: wsl-setup (Ubuntu Resolute)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/2122047
Title:
Case-fold the Windows username before sanitization
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