fix: warn user about deprecated LV_DEFAULT_DRIVE_LETTER

[AndreCostaaa]

Fixes #7614

Like explained here: #7614 (comment)

The line #define LV_FS_DEFAULT_DRIVE_LETTER LV_FS_DEFAULT_DRIVER_LETTER is causing the docs generation workflow to crash when building the examples because of a symbol redefinition. This checks if the symbol is already defined to avoid redefining it

[XuNeo]

Maybe it's better to fix /home/runner/work/lvgl/lvgl/emscripten_builder/lv_conf.h:793:9 to use correct macro?

[AndreCostaaa]

Maybe it's better to fix /home/runner/work/lvgl/lvgl/emscripten_builder/lv_conf.h:793:9 to use correct macro?

So that's where the config comes from ! To be honest i should've checked the build script before but i guess it's never too late

But it seems like a nightmare to maintain a config in another repository that can easily break. Would moving the config to this repository and copying it during the build process be a viable option?

[liamHowatt]

There are three reasons the docs build is failing. I fixed it in this PR: lvgl/lv_web_emscripten#26 🙂

This is an important PR in general, I think.

[AndreCostaaa]

Nice one! We can close this one then

[AndreCostaaa]

This is an important PR in general, I think.

I don't follow. In what sense is it important?

[liamHowatt]

When that config got renamed, there were two mechanisms added both trying to solve the same problem. This line in the API map, and the below.

lvgl/scripts/lv_conf_internal_gen.py

Lines 91 to 94 in 05a0395

	/* Renamed config backwards-compatibility */
	#if !defined(LV_FS_DEFAULT_DRIVER_LETTER) && defined(LV_FS_DEFAULT_DRIVE_LETTER)
	#define LV_FS_DEFAULT_DRIVER_LETTER LV_FS_DEFAULT_DRIVE_LETTER
	#endif

I don't feel great about either. I think maybe the one in lv_conf_internal_gen.py could go away, and the one in lv_api_map_v9_1.h could become

#ifdef LV_FS_DEFAULT_DRIVE_LETTER
#error deprecate config name. Rename to LV_FS_DEFAULT_DRIVER_LETTER
#endif

but that's just a 30 second idea. Open to any ideas whatsoever.

[AndreCostaaa]

Thank you for clarifying. I understand now

On one hand I understand the idea of keeping backwards compatibility. On the other hand, the fact that the internal generation script got changed to add this feels a bit hacky imo

Also, I think that the user should at least get a warning if they're using a deprecated config. What do you think of removing this :

lvgl/scripts/lv_conf_internal_gen.py

Lines 91 to 94 in 05a0395

	/* Renamed config backwards-compatibility */
	#if !defined(LV_FS_DEFAULT_DRIVER_LETTER) && defined(LV_FS_DEFAULT_DRIVE_LETTER)
	#define LV_FS_DEFAULT_DRIVER_LETTER LV_FS_DEFAULT_DRIVE_LETTER
	#endif

And redefining it while providing a #warning inside lv_api_map_v9_1.h instead ?
Something like:

#ifdef LV_FS_DEFAULT_DRIVE_LETTER
    #define LV_FS_DEFAULT_DRIVER_LETTER LV_FS_DEFAULT_DRIVE_LETTER
    #warning deprecate config name. Rename to LV_FS_DEFAULT_DRIVER_LETTER
#endif

[liamHowatt]

Thanks for doing this.

[liamHowatt]

I think this must be close to the best solution. Thanks. I think that '\0' check is a really good idea.