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bootutil: add fallthrough to fix implicit fallthrough warning #2705

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bootutil: add fallthrough to fix implicit fallthrough warning #2705

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2 changes: 1 addition & 1 deletion boot/bootutil/src/bootutil_public.c
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Original file line number Diff line number Diff line change
Expand Up @@ -622,7 +622,7 @@ boot_set_next(const struct flash_area *fa, bool active, bool confirm)
if (rc != 0) {
break;
}
/* Pass */
/* fallthrough */
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@nordicjm nordicjm Apr 24, 2026

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not sure I follow this, it appears to be a C23 feature and is done using [] style brackets https://en.cppreference.com/c/language/attributes/fallthrough - not that doing that would be acceptable in MCUboot because of supporting old compilers. Do you have a reference to something this fixes?

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@supperthomas supperthomas Apr 24, 2026 •
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mcuboot/boot/bootutil/src/loader.c

Lines 1838 to 1842 in 95a6e38

case BOOT_SWAP_TYPE_TEST:
/* fallthrough */
case BOOT_SWAP_TYPE_PERM:
if (check_downgrade_prevention(state) != 0) {
/* Downgrade prevented */

When I enable the fallthrough compilation warning as an error, an error is reported during compilation at this code segment. I have made corresponding modifications by referring to other loader.c files, which should theoretically comply with the modification conventions of MCUboot. If the old compiler fails to handle this part properly, other code areas would presumably encounter the same issue as well.

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@supperthomas supperthomas Apr 27, 2026

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@nordicjm So, how to fix for the warning error?

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@nordicjm nordicjm Apr 27, 2026

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@d3zd3z


case BOOT_MAGIC_GOOD:
if (confirm) {
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