coverity: avoid dereferencing NULL #28949

Job	Run time
config	8s
fuzz smoke test	2m 39s
win build	5m 10s
sparse	4m 35s
win+Meson build	4m 14s
documentation	8m 34s
static-analysis	6m 17s
osx-gcc (macos-14)	38m 37s
osx-clang (macos-14)	32m 14s
rust-analysis	1m 54s
osx-reftable (macos-14)	33m 19s
osx-meson (macos-14)	50m 40s
linux-asan-ubsan (ubuntu:rolling)	1h 11m 43s
linux-meson (ubuntu:rolling)	25m 5s
linux-sha256 (ubuntu:rolling)	25m 26s
linux-musl-meson (alpine:latest)	19m 16s
linux-reftable-leaks (ubuntu:rolling)	14s
almalinux-8 (almalinux:8)	24m 50s
linux-breaking-changes (ubuntu:rolling)	28m 55s
linux32 (i386/ubuntu:20.04)	6h 0m 3s
debian-11 (debian:11)	22m 7s
linux-reftable (ubuntu:rolling)	22m 58s
linux-TEST-vars (ubuntu:20.04)	21m 12s
win+VS build	0s
fedora-breaking-changes-meson (fedora:latest)	23m 8s
linux-leaks (ubuntu:rolling)	59m 59s
win+VS test	0s
win+Meson test (0)	10m 22s
win+Meson test (2)	8m 39s
win+Meson test (4)	8m 53s
win+Meson test (9)	10m 34s
win+Meson test (1)	6m 17s
win+Meson test (6)	41m 0s
win+Meson test (5)	10m 56s
win+Meson test (3)	58m 37s
win+Meson test (7)	9m 35s
win+Meson test (8)	8m 39s
win test (6)	59m 27s
win test (0)	8m 45s
win test (8)	7m 30s
win test (9)	7m 3s
win test (2)	6m 34s
win test (1)	7m 35s
win test (7)	18m 46s
win test (3)	10m 51s
win test (4)	7m 12s
win test (5)	9m 19s
	20h 9m 51s

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