Search filter is case sensitive for non ASCII characters

[JackGruber]

When you have tags/notebooks with mixed case and a non ASCII char is uppercase/lowercase you can't search for them with the wrong case in the search filter.

Affected filter:

• tag
• notebook

Environment

Joplin 2.1.0 (dev, win32)

Sync Version: 2
Profile Version: 39
Keychain Supported: Yes

Steps to reproduce

Tag

1. Import Notes with mixedcase or upper case tags like AÜW
2. Search: tag:aüw = no search results
3. Search: tag:aÜw = search results

Notebook

1. Create a notebook AÜW
2. Create some notes in the notebook
3. Search: notebook:aüw = no search results
4. Search: notebook:aÜw = search results

Describe what you expected to happen

You can filter even if you don't know the exact casing.

More info

(18) Case-insensitive matching of Unicode characters does not work.
https://www.sqlite.org/faq.html#q18

SQL Example:
SELECT LOWER('MY TEST STRING with non ASCII ÜÄÖÉ ...') AS test;

test
my test string with non ascii char ÜÄÖÉ ...

One possible solution would be to overload the default LOWER() function.

[laurent22]

In the normalizeText function of the search engine, I see the diacritics are already removed so in theory it should work. But maybe for some reason certain letters aren't processed properly.

[JackGruber]

Tags and notebook filter directly on the tags and folder table with LIKE.
If I see it correctly, only the note text is normalised.

[laurent22]

Good point. That might be trickier than I thought then as if we can't use the LOWER function, it means we need to normalize folder and tag titles in a separate table too.