fix(test): fix memory leak on failed screenshot compare

[kisvegabor]

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[github-actions]

Hi 👋, thank you for your PR!

We've run benchmarks in an emulated environment. Here are the results:

ARM Emulated 32b - lv_conf_perf32b

Scene Name	Avg CPU (%)	Avg FPS	Avg Time (ms)	Render Time (ms)	Flush Time (ms)
All scenes avg.	27 (-1)	37	7	7	0

Detailed Results Per Scene

Scene Name	Avg CPU (%)	Avg FPS	Avg Time (ms)	Render Time (ms)	Flush Time (ms)
Empty screen	11	33	0	0	0
Moving wallpaper	2	33	1	1	0
Single rectangle	0	50	0	0	0
Multiple rectangles	0	39 (+4)	0	0	0
Multiple RGB images	0	39	0	0	0
Multiple ARGB images	7 (-2)	43 (+1)	0	0	0
Rotated ARGB images	56 (+1)	44	15	15	0
Multiple labels	7 (+2)	33	0	0	0
Screen sized text	95 (-2)	47	20	20	0
Multiple arcs	33 (-5)	33	7	7	0
Containers	4 (+1)	36 (-1)	0	0	0
Containers with overlay	88	21	44	44	0
Containers with opa	6 (-8)	36 (-1)	1	1	0
Containers with opa_layer	18	33 (-1)	5	5	0
Containers with scrolling	45 (-1)	46 (-1)	12	12	0
Widgets demo	67 (-1)	40	16	16	0
All scenes avg.	27 (-1)	37	7	7	0

ARM Emulated 64b - lv_conf_perf64b

Scene Name	Avg CPU (%)	Avg FPS	Avg Time (ms)	Render Time (ms)	Flush Time (ms)
All scenes avg.	23	38	6	6	0

Detailed Results Per Scene

Scene Name	Avg CPU (%)	Avg FPS	Avg Time (ms)	Render Time (ms)	Flush Time (ms)
Empty screen	11	33	0	0	0
Moving wallpaper	1	33	0	0	0
Single rectangle	0	49	0	0	0
Multiple rectangles	0	45	0	0	0
Multiple RGB images	0	39	0	0	0
Multiple ARGB images	1	38	0	0	0
Rotated ARGB images	30	33	9	9	0
Multiple labels	2	40 (+4)	0	0	0
Screen sized text	76 (-1)	45	17	17	0
Multiple arcs	25	33	6	6	0
Containers	1 (-3)	38 (+1)	0	0	0
Containers with overlay	97 (+8)	23	41	41	0
Containers with opa	16 (+3)	37 (-1)	0	0	0
Containers with opa_layer	9 (+2)	37 (-1)	2 (+1)	2 (+1)	0
Containers with scrolling	44 (-2)	46 (-1)	11	11	0
Widgets demo	66	42	15 (+1)	15 (+1)	0
All scenes avg.	23	38	6	6	0

Disclaimer: These benchmarks were run in an emulated environment using QEMU with instruction counting mode.
The timing values represent relative performance metrics within this specific virtualized setup and should
not be interpreted as absolute real-world performance measurements. Values are deterministic and useful for
comparing different LVGL features and configurations, but may not correlate directly with performance on
physical hardware. The measurements are intended for comparative analysis only.

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🤖 This comment was automatically generated by a bot.

[cubic-dev-ai]

No issues found across 1 file

[AndreCostaaa]

I wonder why the CI is failing

[Copilot]

Pull Request Overview

Fix memory leak paths in screenshot comparison tests when the reference image is missing or dimensions mismatch.

• Add missing lv_draw_buf_destroy(ref_draw_buf) before early returns
• Free screen buffer on dimension mismatch path to prevent leaks

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_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Copilot]

The return value of write_png_file is ignored, which can mask failures to write the reference image. Consider checking the result and returning false (or logging an error) on failure, ensuring cleanup still happens.

Suggested change

	write_png_file(screen_buf_xrgb8888, draw_buf->header.w, draw_buf->header.h, fn_ref_full);
	lv_free(screen_buf_xrgb8888);
	lv_draw_buf_destroy(ref_draw_buf);
	unsigned write_res = write_png_file(screen_buf_xrgb8888, draw_buf->header.w, draw_buf->header.h, fn_ref_full);
	lv_free(screen_buf_xrgb8888);
	lv_draw_buf_destroy(ref_draw_buf);
	if(write_res) {
	LV_LOG_ERROR("Failed to write reference image to %s (error code: %u)", fn_ref_full, write_res);
	return false;
	}

[Copilot]

[nitpick] Cleanup logic is duplicated across early returns. Consider consolidating cleanup into a single block (e.g., a cleanup label) and using a status variable to reduce future drift when adding/removing resources.

[Copilot]

[nitpick] Cleanup logic is duplicated across early returns. Consider consolidating cleanup into a single block (e.g., a cleanup label) and using a status variable to reduce future drift when adding/removing resources.

[AndreCostaaa]

As we have previously discussed, this line is very suspicious. I don't understand how we actually create this lv_draw_buf_t correctly

[liamHowatt]

It looks like we modified lodepng to work with draw_bufs.