randomizer: do not pass NULL to memcpy()

When switching playback order from NORMAL to RANDOM, the current playlist items are added to the randomizer.

However, if the playlist is empty, the items vector is empty, and its `.data field is NULL. This causes the following error in ASAN:

../../src/playlist/randomizer.c:426:10: runtime error: null pointer passed as argument 2, which is declared to never be null

If the playlist size is 0, then do not call randomizer_Add() at all.

changed milestone to %4.0

approved this merge request

Why not do the check directly in randomizer_Add() ? There seems to be more cases where this might happen. And the fact it's using memcpy() internally doesn't seem related to the place you're changing the code.

The change is more likely needed in the vlc_vector_insert_all() functionmacro.

Something like

#define vlc_vector_insert_all(pv, index, items, count) \
( \
    vlc_vector_check_same_ptr_type_((pv)->data, items), \
    vlc_vector_insert_hole(pv, index, count) && \
    ( \
        count ? memcpy(&(pv)->data[index], items, (count) * sizeof(*(pv)->data)) : (void) count, \
        true \
    ) \
)

I prefer the check on the outside of randomizer_Add and the addition of an assert/unreachable in randomizer_Add given that adding zero items doesn't seem like a legit use case.

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added 1 commit

• 4ba3fae5 - vlc_vector: assert count argument is not 0

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added 61 commits

• 4ba3fae5...46e9fb37 - 59 commits from branch videolan:master
• 279758e3 - randomizer: do not pass NULL to memcpy()
• 5ebf9e28 - vlc_vector: assert count argument is not 0

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merged