Editing style with multiple instances of module loses instance

[kofa73]

Describe the bug/issue lighttable -> styles -> edit -> update corrupts style if multiple instances are selected for update

To Reproduce

1. Open an image
2. Apply 2 instances of a module (I used contrast EQ / atrous with the built-in clarity and deblur: large blur, strength 3 presets). Name the instances (I used the names 'clarity' and 'deblur).
3. From the history stack, create a style with the 2 module instances.
4. In lighttable, export the preset to a dtstyle file.
5. With the same image selected as the one from which the style was created, click edit in the lighttable's styles menu.
6. Select the module instances to update the style.
7. Export the updated style.
8. Edit the style again. It'll show the same module instance twice:
9. Apply the updated style to an image.

Expected behavior

1. Exported files are identical (2 instances of the module with the same sets of settings)
2. After-update version of the style is the same as the one original one.

My exported dtstyles before/after the update are at https://tech.kovacs-telekes.org/files/2021-04-04-style-with-multiple-instances-of-module/clarity-plus-deblur.zip

Might be related to #7581? Though, for me, creating the style works; it's the update that's broken.

Which commit introduced the error Went back to 3.4.1, the problem is present. Then to 3.0.2, still present. Maybe this never worked?

Platform

• darktable version : 3.5.0+1560~g1eb0866d0
• OS : Linux, kernel 5.8.0-48-generic
• Linux - Distro : e.g. Ubuntu 20.10
• Memory : 64 GB
• Graphics card : NVidia 1060/6GB
• Graphics driver : 450.102.04-0ubuntu0.20.10.1
• OpenCL installed : nvidia-opencl-dev: 11.0.3-1ubuntu1, ocl-icd-libopencl1: 2.2.12-4
• OpenCL activated : yes
• Xorg : 1:7.7+19ubuntu15
• Desktop : KDE 5.74.0
• GTK+ : 3.24.23
• gcc : 10.2.0-1ubuntu1
• cflags : ?
• CMAKE_BUILD_TYPE : ?

I just use the supplied build.sh without any magic.

Additional context

• Are the steps above reproducible with a fresh edit (i.e. after discarding history)? yes
• Is the issue still present using an empty/new config-dir (e.g. start darktable with --configdir "/tmp")? yes

[TurboGit]

Point 6 is where the bug is as in 7 the dtstyle contains the same instance name.

[TurboGit]

Thanks for the report, should be fixed on master.

[kofa73]

Confirmed: it is fixed, indeed. Thanks for the quick reaction.

[TurboGit]

Thanks for confirming !