Split vector layers returns incorrect layer names

[rnanclares]

Describe the bug
When using the split vector layer tool the resulting layers have incorrect names, like attribute_name + index[0,1,2,3,4,5,...] but it should be attribute name + attribute value. It happens with text and numeric fields and using different output formats (gpkg, shp).

How to Reproduce

1. Go to Split Vector layer tool in processing
2. Split layer using Unique ID Field
3. Save layers to folder
4. Resulting layers have incorrect names

QGIS and OS versions

QGIS 3.13
Ubuntu 20.04

Additional context
Test gpkg
split_test.zip

[gioman]

Confirmed here.

[uclaros]

I believe it's intentionally that way. The unique ID field may be of any type and any length like unlimited length TEXT or even BLOB, that can't be put on a filename.

[gioman]

I believe it's intentionally that way. The unique ID field may be of any type and any length like unlimited length TEXT or even BLOB, that can't be put on a filename.

@uclaros right, but is an extremely common case using a "normal" attribute, and what the user is looking for is to have this attribute used in the resulting files/layers names.

[rnanclares]

@uclaros It's a regression, it doesn't happen in 3.10 or 3.12

[Giacominibus]

Describe the bug
When using the split vector layer tool the resulting layers have incorrect names, like attribute_name + index[0,1,2,3,4,5,...] but it should be attribute name + attribute value. It happens with text and numeric fields and using different output formats (gpkg, shp).

How to Reproduce

1. Go to Split Vector layer tool in processing
2. Split layer using Unique ID Field
3. Save layers to folder
4. Resulting layers have incorrect names

QGIS and OS versions

QGIS 3.13
Ubuntu 20.04

Additional context
Test gpkg
split_test.zip

Confirmed for QGIS 3.14.0-Pi on Windows 10 64 bit