QField casting of UUID vs desktop QGIS

[antoineouellet]

Describe the issue

QField seems to handle casting of UUIDs to string differently than QGIS, with the result being inconsistent data whether it is digitized on mobile or on desktop.

QGIS casts UUID types to its pure hex representation (e.g. '9ec9a230-4866-4e45-ab59-b8610b02711f') whereas it is cast to brackets in QField (e.g. '{9ec9a230-4866-4e45-ab59-b8610b02711f}').

Reproduction steps

Steps to reproduce the behavior:

1. For a layer, make an uuid autogenerated field (form field uneditable, default uuid() )
2. Make a virtual field with expression left(to_string("uuid"),4).
3. Digitize a new entry on desktop, with automatic uuid. Virtual field shows: 9ec9.
4. Digitize a new entry on mobile, with automatic uuid. Virtual field shows: {9ec.

Expected behavior

QField represents uuid as '{xxx}' whereas QGIS represents uuid as 'xxx'. I would expect it to be consistent, preferably 'xxx'.

Screenshots and GIFs

Showing entries on QField, we can see which ones were digitized previously on desktop, and which one in mobile session.

QGIS (please complete the following information)

• OS: Linux
• QGIS Version 3.36.1
• QFieldSync Version 4.11.10

QField (please complete the following information)

• Device: Pixel 6a
• OS: Android 14
• QField version: 3.4.5

Additional information

• Problem started happening recently, didn't happen in an older version of QField: No
• Problem can be reliably reproduced, doesn't happen randomly: Yes
• Problem happens with all files and projects, not only some files or projects: so far Yes

[nirvn]

@antoineouellet , uuid() format varies across platforms (e.g. on Windows you won't have the {} by default whereas on Linux and Android they are present).

The solution is to explicitly asks for generated uuids without braces through the following function parameter: uuid('WithoutBraces').

Happy field mapping!