Gc.collect() Causes Crash

I want to use the manual garbage collection but I’m not able to.

import lvgl as lv
from ili9XXX import ili9341
from xpt2046 import xpt2046
import gc

# Load TFT Driver
disp = ili9341(spihost=2, miso=19, mosi=23, clk=18, cs=15, dc=13, rst=0, backlight=27, mhz=10, factor=8, half_duplex=False, double_buffer=True, power=-1, power_on=1, backlight_on=1)
# Load Touch Driver
touch = xpt2046(spihost=2, cs=5, cal_x0 = 242, cal_y0 = 3948, cal_x1 = 3783, cal_y1 = 423)
# Screen elements
scr = lv.scr_act()
cnt_lbl = lv.label(scr)
cnt_lbl.set_style_text_font(lv.font_montserrat_48, 0)
cnt_lbl.set_align(lv.ALIGN.TOP_MID)
cnt_lbl.set_pos(0, 60)
cnt_lbl.set_text('0')
lv.scr_load(scr)

gc.collect()  # If you comment this out, you won't have a crash

You can receive one of two different types of crashes.

Double buffer
ILI9341 initialization completed
Enable backlight
:diamonds::diamonds:>
MicroPython v1.20.0-700-g841ece132-dirty on 2023-09-10; ESP32 module (spiram) with ESP32
Type “help()” for more information.

Traceback (most recent call last):
File “lv_utils.py”, line 124, in task_handler
KeyError: lv_indev_t_read_cb

********** OR **********

Double buffer
ILI9341 initialization completed
Enable backlight
:diamonds::diamonds:>
MicroPython v1.20.0-700-g841ece132-dirty on 2023-09-10; ESP32 module (spiram) with ESP32
Type “help()” for more information.

Guru Meditation Error: Core 1 panic’ed (LoadProhibited). Exception was unhandled.

Core 1 register dump:
PC : 0x40084b99 PS : 0x00060630 A0 : 0x800dd683 A1 : 0x3ffdeb70
A2 : 0x00000006 A3 : 0x00000efa A4 : 0x00000000 A5 : 0x00000006
A6 : 0x003fffff A7 : 0x00060823 A8 : 0x00000000 A9 : 0x3ffdeb60
A10 : 0x3f81c2e0 A11 : 0x3f403f38 A12 : 0x3ffd2118 A13 : 0x00000374
A14 : 0x00000496 A15 : 0x0000000c SAR : 0x0000001c EXCCAUSE: 0x0000001c
EXCVADDR: 0x00000006 LBEG : 0x4009620e LEND : 0x40096219 LCOUNT : 0x00000000

Backtrace: 0x40084b96:0x3ffdeb70 0x400dd680:0x3ffdeba0 0x400ff160:0x3ffdebc0 0x4012834b:0x3ffdebf0 0x40128990:0x3ffdec10 0x40140e58:0x3ffdec60 0x400fcf73:0x3ffdec90 0x400fb7f7:0x3ffdecb0 0x40107661:0x3ffdecd0 0x400e49fe:0x3ffdecf0 0x400e4b4e:0x3ffded10 0x40086515:0x3ffded30 0x400de498:0x3ffdedd0 0x400e49fe:0x3ffdee00 0x40121e7a:0x3ffdee20 0x40121ead:0x3ffdee60 0x400e49fe:0x3ffdee80 0x400e4b07:0x3ffdeea0 0x400e5532:0x3ffdeed0 0x400e56bc:0x3ffdef50 0x400d8839:0x3ffdef70 0x400f0b51:0x3ffdef90 0x400f12a2:0x3ffdefb0 0x400d85d8:0x3ffdeff0

ELF file SHA256: 3de2028db3c2827c

Rebooting…
ets Jul 29 2019 12:21:46

I believe lv_utils.py is the culprit.
I am not using any animated widgets.
Is there a way I can manualy refresh this display using lv.task_handler()
when information changes without the automated refresh.

Explicit code would be appreciated !

To clarify why I need the garbage collection can be demonstrated
with this loop added to the above code…

v.scr_load(scr)

da_num = 0
while da_num <= 100:
    cnt_lbl.set_text(str(da_num))
    da_num +=1
    print(f'\nLoop #:  {str(da_num)}')
    print(f"mem_alloc: {gc.mem_alloc()/1_000_000:.3f}")
    print(f"mem_free: {gc.mem_free()/1_000_000:.3f}")
    time.sleep(.2)

gc.collect()  # If you comment this out, you won't have a crash

After a 100 loops I’ve chewed up a half a meg of heap memory using a SINGLE Label.

Loop #: 1
mem_alloc: 0.027
mem_free: 4.071

Loop #: 2
mem_alloc: 0.031
mem_free: 4.067

by end…

Loop #: 99
mem_alloc: 0.552
mem_free: 3.547

Loop #: 100
mem_alloc: 0.558
mem_free: 3.541

Is this normal to use up to 10 kilobytes on every loop?
Or would this be considered a memory leak?

and then gc.collect() CRASH

So I ran the loop WITHOUT LVGL…

import gc, time

da_num = 0
while da_num <= 100:
    da_num +=1
    print(f'\nLoop #:  {str(da_num)}')
    print(f"mem_alloc: {gc.mem_alloc()/1_000_000:.3f}")
    print(f"mem_free: {gc.mem_free()/1_000_000:.3f}")
    time.sleep(.2)

gc.collect()  # If you comment this out, you won't have a crash
print(f"mem_alloc: {gc.mem_alloc()/1_000_000:.3f}")
print(f"mem_free: {gc.mem_free()/1_000_000:.3f}")

Loop #: 1
mem_alloc: 0.009
mem_free: 4.089

Loop #: 101
mem_alloc: 0.030
mem_free: 4.068

After gc…
mem_alloc: 0.006
mem_free: 4.092

This is s a huge difference.
Why is LVGL using so much resources?

I also ran the loop WITH LVGL but did not update the label

# cnt_lbl.set_text(str(da_num))

Loop #: 100
mem_alloc: 0.548
mem_free: 3.551

Got the same huge memory usage WHY ??
If the screen is not changing where is all the memory going?

Now I replaced while loop with TIMER function…

lv.scr_load(scr)

da_num = 0
def lbl_updt(timer):
    global da_num
    da_num +=1
    if da_num > 100:
        timer._del()
    cnt_lbl.set_text(str(da_num))
    print(f'\nLoop #:  {str(da_num)}')
    print(f"mem_alloc: {gc.mem_alloc()/1_000_000:.3f}")
    print(f"mem_free: {gc.mem_free()/1_000_000:.3f}")
timer = lv.timer_create(lbl_updt, 200, None)

Memory usage has gone down but still large
Loop #: 100
mem_alloc: 0.227
mem_free: 3.871

AND gc.collect() STILL CRASHES CODE

What is the problem with garbage collection ???

How do I stop the automatic loop and create a manual refresh ?
Help much needed !

After further experimentation I put in a clean install of LV_micropython.
Built and then ran my loop, NO ISSUES.
Then I copied my custom lv_config.h file and now the issue with garbage collection have surfaced.
What in the lv_config.h file could cause a gc.collect() issue

/**
 * @file lv_conf.h
 * Configuration file for v9.0.0-dev
 */

/*
 * Copy this file as `lv_conf.h`
 * 1. simply next to the `lvgl` folder
 * 2. or any other places and
 *    - define `LV_CONF_INCLUDE_SIMPLE`
 *    - add the path as include path
 */

/* clang-format off */
#if 1 /*Set it to "1" to enable content*/

#ifndef LV_CONF_H
#define LV_CONF_H

#include <stdint.h>

/*====================
   COLOR SETTINGS
 *====================*/

/*Color depth: 1 (1 byte per pixel), 8 (RGB332), 16 (RGB565), 24 (RGB888), 32 (ARGB8888)*/
#define LV_COLOR_DEPTH 16

#define LV_COLOR_CHROMA_KEY lv_color_hex(0x00ff00)

/*=========================
   STDLIB WRAPPER SETTINGS
 *=========================*/

/*Enable and configure the built-in memory manager*/
#define LV_USE_BUILTIN_MALLOC 1
#if LV_USE_BUILTIN_MALLOC
    /*Size of the memory available for `lv_malloc()` in bytes (>= 2kB)*/
    #define LV_MEM_SIZE (48U * 1024U)          /*[bytes]*/

    /*Size of the memory expand for `lv_malloc()` in bytes*/
    #define LV_MEM_POOL_EXPAND_SIZE 0

    /*Set an address for the memory pool instead of allocating it as a normal array. Can be in external SRAM too.*/
    #define LV_MEM_ADR 0     /*0: unused*/
    /*Instead of an address give a memory allocator that will be called to get a memory pool for LVGL. E.g. my_malloc*/
    #if LV_MEM_ADR == 0
        #undef LV_MEM_POOL_INCLUDE
        #undef LV_MEM_POOL_ALLOC
    #endif
#endif  /*LV_USE_BUILTIN_MALLOC*/

/*Enable lv_memcpy_builtin, lv_memset_builtin, lv_strlen_builtin, lv_strncpy_builtin, lv_strcpy_builtin*/
#define LV_USE_BUILTIN_MEMCPY 1

/*Enable and configure the built-in (v)snprintf */
#define LV_USE_BUILTIN_SNPRINTF 1
#if LV_USE_BUILTIN_SNPRINTF
    #define LV_SPRINTF_USE_FLOAT 0
#endif  /*LV_USE_BUILTIN_SNPRINTF*/

#define LV_STDLIB_INCLUDE <stdint.h>
#define LV_STDIO_INCLUDE  <stdint.h>
#define LV_STRING_INCLUDE <stdint.h>
#define LV_MALLOC       lv_malloc_builtin
#define LV_REALLOC      lv_realloc_builtin
#define LV_FREE         lv_free_builtin
#define LV_MEMSET       lv_memset_builtin
#define LV_MEMCPY       lv_memcpy_builtin
#define LV_SNPRINTF     lv_snprintf_builtin
#define LV_VSNPRINTF    lv_vsnprintf_builtin
#define LV_STRLEN       lv_strlen_builtin
#define LV_STRNCPY      lv_strncpy_builtin
#define LV_STRCPY       lv_strcpy_builtin

#define LV_COLOR_EXTERN_INCLUDE <stdint.h>
#define LV_COLOR_MIX      lv_color_mix
#define LV_COLOR_PREMULT      lv_color_premult
#define LV_COLOR_MIX_PREMULT      lv_color_mix_premult

/*====================
   HAL SETTINGS
 *====================*/

/*Default display refresh, input device read and animation step period.*/
#define LV_DEF_REFR_PERIOD  33      /*[ms]*/

/*Use a custom tick source that tells the elapsed time in milliseconds.
 *It removes the need to manually update the tick with `lv_tick_inc()`)*/
#define LV_TICK_CUSTOM 0
#if LV_TICK_CUSTOM
    #define LV_TICK_CUSTOM_INCLUDE "Arduino.h"         /*Header for the system time function*/
    #define LV_TICK_CUSTOM_SYS_TIME_EXPR (millis())    /*Expression evaluating to current system time in ms*/
    /*If using lvgl as ESP32 component*/
    // #define LV_TICK_CUSTOM_INCLUDE "esp_timer.h"
    // #define LV_TICK_CUSTOM_SYS_TIME_EXPR ((esp_timer_get_time() / 1000LL))
#endif   /*LV_TICK_CUSTOM*/

/*Default Dot Per Inch. Used to initialize default sizes such as widgets sized, style paddings.
 *(Not so important, you can adjust it to modify default sizes and spaces)*/
#define LV_DPI_DEF 130     /*[px/inch]*/

/*========================
 * DRAW CONFIGURATION
 *========================*/

/*Enable the built in mask engine.
 *Required to draw shadow, rounded corners, circles, arc, skew lines, or any other masks*/
#define LV_USE_DRAW_MASKS 1

#define LV_USE_DRAW_SW  1
#if LV_USE_DRAW_SW

    /*Enable complex draw engine.
     *Required to draw shadow, gradient, rounded corners, circles, arc, skew lines, image transformations or any masks*/
    #define LV_DRAW_SW_COMPLEX 1

    /* If a widget has `style_opa < 255` (not `bg_opa`, `text_opa` etc) or not NORMAL blend mode
     * it is buffered into a "simple" layer before rendering. The widget can be buffered in smaller chunks.
     * "Transformed layers" (if `transform_angle/zoom` are set) use larger buffers
     * and can't be drawn in chunks. */

    /*The target buffer size for simple layer chunks.*/
    #define LV_DRAW_SW_LAYER_SIMPLE_BUF_SIZE          (24 * 1024)   /*[bytes]*/

    /*Used if `LV_DRAW_SW_LAYER_SIMPLE_BUF_SIZE` couldn't be allocated.*/
    #define LV_DRAW_SW_LAYER_SIMPLE_FALLBACK_BUF_SIZE (3 * 1024)    /*[bytes]*/

    /*Allow buffering some shadow calculation.
    *LV_DRAW_SW_SHADOW_CACHE_SIZE is the max. shadow size to buffer, where shadow size is `shadow_width + radius`
    *Caching has LV_DRAW_SW_SHADOW_CACHE_SIZE^2 RAM cost*/
    #define LV_DRAW_SW_SHADOW_CACHE_SIZE 0

    /* Set number of maximally cached circle data.
    * The circumference of 1/4 circle are saved for anti-aliasing
    * radius * 4 bytes are used per circle (the most often used radiuses are saved)
    * 0: to disable caching */
    #define LV_DRAW_SW_CIRCLE_CACHE_SIZE 4

    /*Default gradient buffer size.
     *When LVGL calculates the gradient "maps" it can save them into a cache to avoid calculating them again.
     *LV_DRAW_SW_GRADIENT_CACHE_DEF_SIZE sets the size of this cache in bytes.
     *If the cache is too small the map will be allocated only while it's required for the drawing.
     *0 mean no caching.*/
    #define LV_DRAW_SW_GRADIENT_CACHE_DEF_SIZE 0

    /*Allow dithering the gradients (to achieve visual smooth color gradients on limited color depth display)
     *LV_DRAW_SW_GRADIENT_DITHER implies allocating one or two more lines of the object's rendering surface
     *The increase in memory consumption is (32 bits * object width) plus 24 bits * object width if using error diffusion */
    #define LV_DRAW_SW_GRADIENT_DITHER 0
    #if LV_DRAW_SW_GRADIENT_DITHER
        /*Add support for error diffusion dithering.
         *Error diffusion dithering gets a much better visual result, but implies more CPU consumption and memory when drawing.
         *The increase in memory consumption is (24 bits * object's width)*/
        #define LV_DRAW_SW_GRADIENT_DITHER_ERROR_DIFFUSION 0
    #endif

    /*Enable subpixel rendering*/
    #define LV_DRAW_SW_FONT_SUBPX 0
    #if LV_DRAW_SW_FONT_SUBPX
        /*Set the pixel order of the display. Physical order of RGB channels. Doesn't matter with "normal" fonts.*/
        #define LV_DRAW_SW_FONT_SUBPX_BGR 0  /*0: RGB; 1:BGR order*/
    #endif
#endif

/*Use SDL renderer API*/
#define LV_USE_DRAW_SDL 0
#if LV_USE_DRAW_SDL
    #define LV_DRAW_SDL_INCLUDE_PATH <SDL2/SDL.h>
    /*Texture cache size, 8MB by default*/
    #define LV_DRAW_SDL_LRU_SIZE (1024 * 1024 * 8)
    /*Custom blend mode for mask drawing, disable if you need to link with older SDL2 lib*/
    #define LV_DRAW_SDL_CUSTOM_BLEND_MODE (SDL_VERSION_ATLEAST(2, 0, 6))
#endif

/*=====================
 * GPU CONFIGURATION
 *=====================*/

/*Use Arm's 2D acceleration library Arm-2D */
#define LV_USE_GPU_ARM2D 0

/*Use STM32's DMA2D (aka Chrom Art) GPU*/
#define LV_USE_GPU_STM32_DMA2D 0
#if LV_USE_GPU_STM32_DMA2D
    /*Must be defined to include path of CMSIS header of target processor
    e.g. "stm32f769xx.h" or "stm32f429xx.h"*/
    #define LV_GPU_DMA2D_CMSIS_INCLUDE
#endif

/*Use GD32 IPA GPU
 * This adds support for Image Processing Accelerator on GD32F450 and GD32F470 series MCUs
 *
 * NOTE: IPA on GD32F450 has a bug where the fill operation overwrites data beyond the
 * framebuffer. This driver works around it by saving and restoring affected memory, but
 * this makes it not thread-safe. GD32F470 is not affected. */
#define LV_USE_GPU_GD32_IPA 0

/*Use NXP's PXP GPU iMX RTxxx platforms*/
#define LV_USE_GPU_NXP_PXP 0
#if LV_USE_GPU_NXP_PXP
    /*1: Add default bare metal and FreeRTOS interrupt handling routines for PXP (lv_gpu_nxp_pxp_osa.c)
    *   and call lv_gpu_nxp_pxp_init() automatically during lv_init(). Note that symbol SDK_OS_FREE_RTOS
    *   has to be defined in order to use FreeRTOS OSA, otherwise bare-metal implementation is selected.
    *0: lv_gpu_nxp_pxp_init() has to be called manually before lv_init()
    */
    #define LV_USE_GPU_NXP_PXP_AUTO_INIT 0
#endif

/*Use NXP's VG-Lite GPU iMX RTxxx platforms*/
#define LV_USE_GPU_NXP_VG_LITE 0

/*Use SWM341's DMA2D GPU*/
#define LV_USE_GPU_SWM341_DMA2D 0
#if LV_USE_GPU_SWM341_DMA2D
    #define LV_GPU_SWM341_DMA2D_INCLUDE "SWM341.h"
#endif

/*=======================
 * FEATURE CONFIGURATION
 *=======================*/

/*-------------
 * Logging
 *-----------*/

/*Enable the log module*/
#define LV_USE_LOG 0
#if LV_USE_LOG

    /*How important log should be added:
    *LV_LOG_LEVEL_TRACE       A lot of logs to give detailed information
    *LV_LOG_LEVEL_INFO        Log important events
    *LV_LOG_LEVEL_WARN        Log if something unwanted happened but didn't cause a problem
    *LV_LOG_LEVEL_ERROR       Only critical issue, when the system may fail
    *LV_LOG_LEVEL_USER        Only logs added by the user
    *LV_LOG_LEVEL_NONE        Do not log anything*/
    #define LV_LOG_LEVEL LV_LOG_LEVEL_WARN

    /*1: Print the log with 'printf';
    *0: User need to register a callback with `lv_log_register_print_cb()`*/
    #define LV_LOG_PRINTF 0

    /*1: Enable print timestamp;
     *0: Disable print timestamp*/
    #define LV_LOG_USE_TIMESTAMP 1

    /*Enable/disable LV_LOG_TRACE in modules that produces a huge number of logs*/
    #define LV_LOG_TRACE_MEM        1
    #define LV_LOG_TRACE_TIMER      1
    #define LV_LOG_TRACE_INDEV      1
    #define LV_LOG_TRACE_DISP_REFR  1
    #define LV_LOG_TRACE_EVENT      1
    #define LV_LOG_TRACE_OBJ_CREATE 1
    #define LV_LOG_TRACE_LAYOUT     1
    #define LV_LOG_TRACE_ANIM       1
	#define LV_LOG_TRACE_MSG		1

#endif  /*LV_USE_LOG*/

/*-------------
 * Asserts
 *-----------*/

/*Enable asserts if an operation is failed or an invalid data is found.
 *If LV_USE_LOG is enabled an error message will be printed on failure*/
#define LV_USE_ASSERT_NULL          1   /*Check if the parameter is NULL. (Very fast, recommended)*/
#define LV_USE_ASSERT_MALLOC        1   /*Checks is the memory is successfully allocated or no. (Very fast, recommended)*/
#define LV_USE_ASSERT_STYLE         0   /*Check if the styles are properly initialized. (Very fast, recommended)*/
#define LV_USE_ASSERT_MEM_INTEGRITY 0   /*Check the integrity of `lv_mem` after critical operations. (Slow)*/
#define LV_USE_ASSERT_OBJ           0   /*Check the object's type and existence (e.g. not deleted). (Slow)*/

/*Add a custom handler when assert happens e.g. to restart the MCU*/
#define LV_ASSERT_HANDLER_INCLUDE <stdint.h>
#define LV_ASSERT_HANDLER while(1);   /*Halt by default*/

/*-------------
 * Others
 *-----------*/

/*1: Show CPU usage and FPS count
 * Requires `LV_USE_SYSMON = 1`*/
#define LV_USE_PERF_MONITOR 0
#if LV_USE_PERF_MONITOR
    #define LV_USE_PERF_MONITOR_POS LV_ALIGN_BOTTOM_RIGHT

    /*0: Displays performance data on the screen, 1: Prints performance data using log.*/
    #define LV_USE_PERF_MONITOR_LOG_MODE 0
#endif

/*1: Show the used memory and the memory fragmentation
 * Requires `LV_USE_BUILTIN_MALLOC = 1`
 * Requires `LV_USE_SYSMON = 1`*/
#define LV_USE_MEM_MONITOR 0
#if LV_USE_MEM_MONITOR
    #define LV_USE_MEM_MONITOR_POS LV_ALIGN_BOTTOM_LEFT
#endif

/*1: Draw random colored rectangles over the redrawn areas*/
#define LV_USE_REFR_DEBUG 0

/*Maximum buffer size to allocate for rotation.
 *Only used if software rotation is enabled in the display driver.*/
#define LV_DISP_ROT_MAX_BUF (10*1024)

/*Garbage Collector settings
 *Used if lvgl is bound to higher level language and the memory is managed by that language*/
#define LV_ENABLE_GC 0
#if LV_ENABLE_GC != 0
    #define LV_GC_INCLUDE "gc.h"                           /*Include Garbage Collector related things*/
#endif /*LV_ENABLE_GC*/

/*Default image cache size. Image caching keeps some images opened.
 *If only the built-in image formats are used there is no real advantage of caching.
 *With other image decoders (e.g. PNG or JPG) caching save the continuous open/decode of images.
 *However the opened images consume additional RAM.
 *0: to disable caching*/
#define LV_IMG_CACHE_DEF_SIZE 0


/*Number of stops allowed per gradient. Increase this to allow more stops.
 *This adds (sizeof(lv_color_t) + 1) bytes per additional stop*/
#define LV_GRADIENT_MAX_STOPS 2

/* Adjust color mix functions rounding. GPUs might calculate color mix (blending) differently.
 * 0: round down, 64: round up from x.75, 128: round up from half, 192: round up from x.25, 254: round up */
#define LV_COLOR_MIX_ROUND_OFS 0

/*=====================
 *  COMPILER SETTINGS
 *====================*/

/*For big endian systems set to 1*/
#define LV_BIG_ENDIAN_SYSTEM 0

/*Define a custom attribute to `lv_tick_inc` function*/
#define LV_ATTRIBUTE_TICK_INC

/*Define a custom attribute to `lv_timer_handler` function*/
#define LV_ATTRIBUTE_TIMER_HANDLER

/*Define a custom attribute to `lv_disp_flush_ready` function*/
#define LV_ATTRIBUTE_FLUSH_READY

/*Required alignment size for buffers*/
#define LV_ATTRIBUTE_MEM_ALIGN_SIZE 1

/*Will be added where memories needs to be aligned (with -Os data might not be aligned to boundary by default).
 * E.g. __attribute__((aligned(4)))*/
#define LV_ATTRIBUTE_MEM_ALIGN

/*Attribute to mark large constant arrays for example font's bitmaps*/
#define LV_ATTRIBUTE_LARGE_CONST

/*Compiler prefix for a big array declaration in RAM*/
#define LV_ATTRIBUTE_LARGE_RAM_ARRAY

/*Place performance critical functions into a faster memory (e.g RAM)*/
#define LV_ATTRIBUTE_FAST_MEM


/*Export integer constant to binding. This macro is used with constants in the form of LV_<CONST> that
 *should also appear on LVGL binding API such as Micropython.*/
#define LV_EXPORT_CONST_INT(int_value) struct _silence_gcc_warning /*The default value just prevents GCC warning*/

/*Extend the default -32k..32k coordinate range to -4M..4M by using int32_t for coordinates instead of int16_t*/
#define LV_USE_LARGE_COORD 0

/*==================
 *   FONT USAGE
 *===================*/

/*Montserrat fonts with ASCII range and some symbols using bpp = 4
 *https://fonts.google.com/specimen/Montserrat*/
#define LV_FONT_MONTSERRAT_8  0
#define LV_FONT_MONTSERRAT_10 0
#define LV_FONT_MONTSERRAT_12 0
#define LV_FONT_MONTSERRAT_14 1
#define LV_FONT_MONTSERRAT_16 0
#define LV_FONT_MONTSERRAT_18 0
#define LV_FONT_MONTSERRAT_20 1
#define LV_FONT_MONTSERRAT_22 0
#define LV_FONT_MONTSERRAT_24 0
#define LV_FONT_MONTSERRAT_26 0
#define LV_FONT_MONTSERRAT_28 0
#define LV_FONT_MONTSERRAT_30 0
#define LV_FONT_MONTSERRAT_32 0
#define LV_FONT_MONTSERRAT_34 0
#define LV_FONT_MONTSERRAT_36 0
#define LV_FONT_MONTSERRAT_38 0
#define LV_FONT_MONTSERRAT_40 0
#define LV_FONT_MONTSERRAT_42 0
#define LV_FONT_MONTSERRAT_44 0
#define LV_FONT_MONTSERRAT_46 0
#define LV_FONT_MONTSERRAT_48 1

/*Demonstrate special features*/
#define LV_FONT_MONTSERRAT_12_SUBPX      0
#define LV_FONT_MONTSERRAT_28_COMPRESSED 0  /*bpp = 3*/
#define LV_FONT_DEJAVU_16_PERSIAN_HEBREW 0  /*Hebrew, Arabic, Persian letters and all their forms*/
#define LV_FONT_SIMSUN_16_CJK            0  /*1000 most common CJK radicals*/

/*Pixel perfect monospace fonts*/
#define LV_FONT_UNSCII_8  0
#define LV_FONT_UNSCII_16 0

/*Optionally declare custom fonts here.
 *You can use these fonts as default font too and they will be available globally.
 *E.g. #define LV_FONT_CUSTOM_DECLARE   LV_FONT_DECLARE(my_font_1) LV_FONT_DECLARE(my_font_2)*/
#define LV_FONT_CUSTOM_DECLARE

/*Always set a default font*/
#define LV_FONT_DEFAULT &lv_font_montserrat_14

/*Enable handling large font and/or fonts with a lot of characters.
 *The limit depends on the font size, font face and bpp.
 *Compiler error will be triggered if a font needs it.*/
#define LV_FONT_FMT_TXT_LARGE 1

/*Enables/disables support for compressed fonts.*/
#define LV_USE_FONT_COMPRESSED 1

/*Enable drawing placeholders when glyph dsc is not found*/
#define LV_USE_FONT_PLACEHOLDER 1

/*=================
 *  TEXT SETTINGS
 *=================*/

/**
 * Select a character encoding for strings.
 * Your IDE or editor should have the same character encoding
 * - LV_TXT_ENC_UTF8
 * - LV_TXT_ENC_ASCII
 */
#define LV_TXT_ENC LV_TXT_ENC_UTF8

/*Can break (wrap) texts on these chars*/
#define LV_TXT_BREAK_CHARS " ,.;:-_)]}"

/*If a word is at least this long, will break wherever "prettiest"
 *To disable, set to a value <= 0*/
#define LV_TXT_LINE_BREAK_LONG_LEN 0

/*Minimum number of characters in a long word to put on a line before a break.
 *Depends on LV_TXT_LINE_BREAK_LONG_LEN.*/
#define LV_TXT_LINE_BREAK_LONG_PRE_MIN_LEN 3

/*Minimum number of characters in a long word to put on a line after a break.
 *Depends on LV_TXT_LINE_BREAK_LONG_LEN.*/
#define LV_TXT_LINE_BREAK_LONG_POST_MIN_LEN 3

/*The control character to use for signalling text recoloring.*/
#define LV_TXT_COLOR_CMD "#"

/*Support bidirectional texts. Allows mixing Left-to-Right and Right-to-Left texts.
 *The direction will be processed according to the Unicode Bidirectional Algorithm:
 *https://www.w3.org/International/articles/inline-bidi-markup/uba-basics*/
#define LV_USE_BIDI 0
#if LV_USE_BIDI
    /*Set the default direction. Supported values:
    *`LV_BASE_DIR_LTR` Left-to-Right
    *`LV_BASE_DIR_RTL` Right-to-Left
    *`LV_BASE_DIR_AUTO` detect texts base direction*/
    #define LV_BIDI_BASE_DIR_DEF LV_BASE_DIR_AUTO
#endif

/*Enable Arabic/Persian processing
 *In these languages characters should be replaced with an other form based on their position in the text*/
#define LV_USE_ARABIC_PERSIAN_CHARS 0

/*==================
 * WIDGETS
 *================*/

/*Documentation of the widgets: https://docs.lvgl.io/latest/en/html/widgets/index.html*/

#define LV_USE_ANIMIMG    1

#define LV_USE_ARC        1     /* cant remove build will fail*/

#define LV_USE_BAR        1     /* cant remove build will fail*/

#define LV_USE_BTN        1

#define LV_USE_BTNMATRIX  1

#define LV_USE_CALENDAR   1     /* cant remove build will fail*/
#if LV_USE_CALENDAR
    #define LV_CALENDAR_WEEK_STARTS_MONDAY 0
    #if LV_CALENDAR_WEEK_STARTS_MONDAY
        #define LV_CALENDAR_DEFAULT_DAY_NAMES {"Mo", "Tu", "We", "Th", "Fr", "Sa", "Su"}
    #else
        #define LV_CALENDAR_DEFAULT_DAY_NAMES {"Su", "Mo", "Tu", "We", "Th", "Fr", "Sa"}
    #endif

    #define LV_CALENDAR_DEFAULT_MONTH_NAMES {"January", "February", "March",  "April", "May",  "June", "July", "August", "September", "October", "November", "December"}
    #define LV_USE_CALENDAR_HEADER_ARROW 1
    #define LV_USE_CALENDAR_HEADER_DROPDOWN 1
#endif  /*LV_USE_CALENDAR*/

#define LV_USE_CANVAS     0

#define LV_USE_CHART      1     /* cant remove build will fail*/

#define LV_USE_CHECKBOX   0

#define LV_USE_COLORWHEEL 0

#define LV_USE_DROPDOWN   1   /*Requires: lv_label*/

#define LV_USE_IMG        1   /*Requires: lv_label*/

#define LV_USE_IMGBTN     0

#define LV_USE_KEYBOARD   1

#define LV_USE_LABEL      1
#if LV_USE_LABEL
    #define LV_LABEL_TEXT_SELECTION 0 /*Enable selecting text of the label*/
    #define LV_LABEL_LONG_TXT_HINT 0  /*Store some extra info in labels to speed up drawing of very long texts*/
#endif

#define LV_USE_LED        0

#define LV_USE_LINE       1

#define LV_USE_LIST       0

#define LV_USE_MENU       0

#define LV_USE_METER      0

#define LV_USE_MSGBOX     1

#define LV_USE_ROLLER     0   /*Requires: lv_label*/

#define LV_USE_SLIDER     0   /*Requires: lv_bar*/

#define LV_USE_SPAN       0
#if LV_USE_SPAN
    /*A line text can contain maximum num of span descriptor */
    #define LV_SPAN_SNIPPET_STACK_SIZE 64
#endif

#define LV_USE_SPINBOX    0

#define LV_USE_SPINNER    0

#define LV_USE_SWITCH     0

#define LV_USE_TEXTAREA   1   /*Requires: lv_label*/
#if LV_USE_TEXTAREA != 0
    #define LV_TEXTAREA_DEF_PWD_SHOW_TIME 1500    /*ms*/
#endif

#define LV_USE_TABLE      0

#define LV_USE_TABVIEW    0

#define LV_USE_TILEVIEW   0

#define LV_USE_WIN        1

/*==================
 * THEMES
 *==================*/

/*A simple, impressive and very complete theme*/
#define LV_USE_THEME_DEFAULT 1
#if LV_USE_THEME_DEFAULT

    /*0: Light mode; 1: Dark mode*/
    #define LV_THEME_DEFAULT_DARK 0

    /*1: Enable grow on press*/
    #define LV_THEME_DEFAULT_GROW 1

    /*Default transition time in [ms]*/
    #define LV_THEME_DEFAULT_TRANSITION_TIME 80
#endif /*LV_USE_THEME_DEFAULT*/

/*A very simple theme that is a good starting point for a custom theme*/
#define LV_USE_THEME_BASIC 1

/*A theme designed for monochrome displays*/
#define LV_USE_THEME_MONO 1

/*==================
 * LAYOUTS
 *==================*/

/*A layout similar to Flexbox in CSS.*/
#define LV_USE_FLEX 1

/*A layout similar to Grid in CSS.*/
#define LV_USE_GRID 1

/*====================
 * 3RD PARTS LIBRARIES
 *====================*/

/*File system interfaces for common APIs */

/*API for fopen, fread, etc*/
#define LV_USE_FS_STDIO 0
#if LV_USE_FS_STDIO
    #define LV_FS_STDIO_LETTER '\0'     /*Set an upper cased letter on which the drive will accessible (e.g. 'A')*/
    #define LV_FS_STDIO_PATH ""         /*Set the working directory. File/directory paths will be appended to it.*/
    #define LV_FS_STDIO_CACHE_SIZE 0    /*>0 to cache this number of bytes in lv_fs_read()*/
#endif

/*API for open, read, etc*/
#define LV_USE_FS_POSIX 0
#if LV_USE_FS_POSIX
    #define LV_FS_POSIX_LETTER '\0'     /*Set an upper cased letter on which the drive will accessible (e.g. 'A')*/
    #define LV_FS_POSIX_PATH ""         /*Set the working directory. File/directory paths will be appended to it.*/
    #define LV_FS_POSIX_CACHE_SIZE 0    /*>0 to cache this number of bytes in lv_fs_read()*/
#endif

/*API for CreateFile, ReadFile, etc*/
#define LV_USE_FS_WIN32 0
#if LV_USE_FS_WIN32
    #define LV_FS_WIN32_LETTER '\0'     /*Set an upper cased letter on which the drive will accessible (e.g. 'A')*/
    #define LV_FS_WIN32_PATH ""         /*Set the working directory. File/directory paths will be appended to it.*/
    #define LV_FS_WIN32_CACHE_SIZE 0    /*>0 to cache this number of bytes in lv_fs_read()*/
#endif

/*API for FATFS (needs to be added separately). Uses f_open, f_read, etc*/
#define LV_USE_FS_FATFS 0
#if LV_USE_FS_FATFS
    #define LV_FS_FATFS_LETTER '\0'     /*Set an upper cased letter on which the drive will accessible (e.g. 'A')*/
    #define LV_FS_FATFS_CACHE_SIZE 0    /*>0 to cache this number of bytes in lv_fs_read()*/
#endif

/*PNG decoder library*/
#define LV_USE_PNG 0

/*BMP decoder library*/
#define LV_USE_BMP 0

/* JPG + split JPG decoder library.
 * Split JPG is a custom format optimized for embedded systems. */
#define LV_USE_SJPG 0

/*GIF decoder library*/
#define LV_USE_GIF 0

/*QR code library*/
#define LV_USE_QRCODE 0

/*Barcode code library*/
#define LV_USE_BARCODE 0

/*FreeType library*/
#define LV_USE_FREETYPE 0
#if LV_USE_FREETYPE
    /*Memory used by FreeType to cache characters [bytes]*/
    #define LV_FREETYPE_CACHE_SIZE (64 * 1024)

    /*Let FreeType to use LVGL memory and file porting*/
    #define LV_FREETYPE_USE_LVGL_PORT 0

    /* 1: bitmap cache use the sbit cache, 0:bitmap cache use the image cache. */
    /* sbit cache:it is much more memory efficient for small bitmaps(font size < 256) */
    /* if font size >= 256, must be configured as image cache */
    #define LV_FREETYPE_SBIT_CACHE 0

    /* Maximum number of opened FT_Face/FT_Size objects managed by this cache instance. */
    /* (0:use system defaults) */
    #define LV_FREETYPE_CACHE_FT_FACES 4
    #define LV_FREETYPE_CACHE_FT_SIZES 4
#endif

/* Built-in TTF decoder */
#define LV_USE_TINY_TTF 0
#if LV_USE_TINY_TTF
    /* Enable loading TTF data from files */
    #define LV_TINY_TTF_FILE_SUPPORT 0
#endif

/*Rlottie library*/
#define LV_USE_RLOTTIE 0

/*FFmpeg library for image decoding and playing videos
 *Supports all major image formats so do not enable other image decoder with it*/
#define LV_USE_FFMPEG 0
#if LV_USE_FFMPEG
    /*Dump input information to stderr*/
    #define LV_FFMPEG_DUMP_FORMAT 0
#endif

/*==================
 * OTHERS
 *==================*/

/*1: Enable API to take snapshot for object*/
#define LV_USE_SNAPSHOT 0

/*1: Enable system monitor component*/
#define LV_USE_SYSMON 0

/*1: Enable the runtime performance profiler*/
#define LV_USE_PROFILER 0
#if LV_USE_PROFILER
    /*1: Enable the built-in profiler*/
    #define LV_USE_PROFILER_BUILTIN 1
    #if LV_USE_PROFILER_BUILTIN
        /*Default profiler trace buffer size*/
        #define LV_PROFILER_BUILTIN_BUF_SIZE (16 * 1024)     /*[bytes]*/
    #endif

    /*Header to include for the profiler*/
    #define LV_PROFILER_INCLUDE "lvgl/src/misc/lv_profiler_builtin.h"

    /*Profiler start point function*/
    #define LV_PROFILER_BEGIN   LV_PROFILER_BUILTIN_BEGIN

    /*Profiler end point function*/
    #define LV_PROFILER_END     LV_PROFILER_BUILTIN_END
#endif

/*1: Enable Monkey test*/
#define LV_USE_MONKEY 0

/*1: Enable grid navigation*/
#define LV_USE_GRIDNAV 0

/*1: Enable lv_obj fragment*/
#define LV_USE_FRAGMENT 0

/*1: Support using images as font in label or span widgets */
#define LV_USE_IMGFONT 0
#if LV_USE_IMGFONT
    /*Imgfont image file path maximum length*/
    #define LV_IMGFONT_PATH_MAX_LEN 64

    /*1: Use img cache to buffer header information*/
    #define LV_IMGFONT_USE_IMG_CACHE_HEADER 0
#endif

/*1: Enable a published subscriber based messaging system */
#define LV_USE_MSG 0

/*1: Enable Pinyin input method*/
/*Requires: lv_keyboard*/
#define LV_USE_IME_PINYIN 0
#if LV_USE_IME_PINYIN
    /*1: Use default thesaurus*/
    /*If you do not use the default thesaurus, be sure to use `lv_ime_pinyin` after setting the thesauruss*/
    #define LV_IME_PINYIN_USE_DEFAULT_DICT 1
    /*Set the maximum number of candidate panels that can be displayed*/
    /*This needs to be adjusted according to the size of the screen*/
    #define LV_IME_PINYIN_CAND_TEXT_NUM 6

    /*Use 9 key input(k9)*/
    #define LV_IME_PINYIN_USE_K9_MODE      1
    #if LV_IME_PINYIN_USE_K9_MODE == 1
        #define LV_IME_PINYIN_K9_CAND_TEXT_NUM 3
    #endif // LV_IME_PINYIN_USE_K9_MODE
#endif

/*1: Enable file explorer*/
/*Requires: lv_table*/
#define LV_USE_FILE_EXPLORER                     0
#if LV_USE_FILE_EXPLORER
    /*Maximum length of path*/
    #define LV_FILE_EXPLORER_PATH_MAX_LEN        (128)
    /*Quick access bar, 1:use, 0:not use*/
    /*Requires: lv_list*/
    #define LV_FILE_EXPLORER_QUICK_ACCESS        1
#endif

/*==================
 * DEVICES
 *==================*/

/*Use SDL to open window on PC and handle mouse and keyboard*/
#define LV_USE_SDL              0
#if LV_USE_SDL
    #define LV_SDL_INCLUDE_PATH    <SDL2/SDL.h>
    #define LV_SDL_PARTIAL_MODE    0    /*Recommended only to emulate a setup with a display controller*/
    #define LV_SDL_FULLSCREEN      0
    #define LV_SDL_DIRECT_EXIT     1    /*1: Exit the application when all SDL widows are closed*/
#endif

/*Driver for /dev/fb*/
#define LV_USE_LINUX_FBDEV      0
#if LV_USE_LINUX_FBDEV
    #define LV_LINUX_FBDEV_BSD  0
#endif

/*Driver for /dev/dri/card*/
#define LV_USE_LINUX_DRM        0

/*Interface for TFT_eSPI*/
#define LV_USE_TFT_ESPI         0

/*==================
* EXAMPLES
*==================*/

/*Enable the examples to be built with the library*/
#define LV_BUILD_EXAMPLES 0     /* cant remove build will fail*/

/*===================
 * DEMO USAGE
 ====================*/

/*Show some widget. It might be required to increase `LV_MEM_SIZE` */
#define LV_USE_DEMO_WIDGETS 0
#if LV_USE_DEMO_WIDGETS
    #define LV_DEMO_WIDGETS_SLIDESHOW 0
#endif

/*Demonstrate the usage of encoder and keyboard*/
#define LV_USE_DEMO_KEYPAD_AND_ENCODER 0

/*Benchmark your system*/
#define LV_USE_DEMO_BENCHMARK 0
#if LV_USE_DEMO_BENCHMARK
    /*Use RGB565A8 images with 16 bit color depth instead of ARGB8565*/
    #define LV_DEMO_BENCHMARK_RGB565A8 0
#endif

/*Stress test for LVGL*/
#define LV_USE_DEMO_STRESS 0

/*Music player demo*/
#define LV_USE_DEMO_MUSIC 0
#if LV_USE_DEMO_MUSIC
    #define LV_DEMO_MUSIC_SQUARE    0
    #define LV_DEMO_MUSIC_LANDSCAPE 0
    #define LV_DEMO_MUSIC_ROUND     0
    #define LV_DEMO_MUSIC_LARGE     0
    #define LV_DEMO_MUSIC_AUTO_PLAY 0
#endif

/*Flex layout demo*/
#define LV_USE_DEMO_FLEX_LAYOUT 0

/*--END OF LV_CONF_H--*/

#endif /*LV_CONF_H*/

#endif /*End of "Content enable"*/

Hard to tell, its quite a big file. Could you perhaps compare the lv_conf files from both projects and point out which lines are different?

lv_conf_template.h should not be used to create a lv_conf.h file as stated in the doc.

There already is a lv_micropython\lib\lv_bindings\lv_conf.h in the repo that was never there before.
Modifying this file with the settings that I wanted, everything now works.
Who would ever think that getting a garbage collection error would be caused by a LVGL config file.

I see. Good find, I guess the documentation is intended for the regular old C version