On Fri, Jul 29, 2022 at 4:33 AM Ævar Arnfjörð Bjarmason
[off-list ref] wrote:

Fix a bug in 0139c58ab95 (revisions API users: add "goto cleanup" for
release_revisions(), 2022-04-13), in that commit a release_revisions()
call was added to this function, but it never did anything due to this
TODO memset() added in fe1a21d5267 (fast-rebase: demonstrate
merge-ort's API via new test-tool command, 2020-10-29).

Simply removing the memset() will fix the "cmdline" which can be seen
when running t5520-pull.sh.

This sort of thing could be detected automatically with a rule similar
to the unused.cocci merged in 7fa60d2a5b6 (Merge branch
'ab/cocci-unused' into next, 2022-07-11). The following rule on top
would catch the case being fixed here:

        @@
        type T;
        identifier I;
        identifier REL1 =~ "^[a-z_]*_(release|reset|clear|free)$";
        identifier REL2 =~ "^(release|clear|free)_[a-z_]*$";
        @@

        - memset(\( I \| &I \), 0, ...);
          ... when != \( I \| &I \)
        (
          \( REL1 \| REL2 \)( \( I \| &I \), ...);
        |
          \( REL1 \| REL2 \)( \( &I \| I \) );
        )
          ... when != \( I \| &I \)

That rule should arguably use only &I, not I (as we might be passed a
pointer). He distinction would matter if anyone cared about the

s/He/The/

side-effects of a memset() followed by release() of a pointer to a
variable passed into the function.

As such a pattern would be at best very confusing, and most likely
point to buggy code as in this case, the above rule is probably fine
as-is.

But as this rule only found one such bug in the entire codebase let's
not add it to contrib/coccinelle/unused.cocci for now, we can always
dig it up in the future if it's deemed useful.

Signed-off-by: Ævar Arnfjörð Bjarmason <redacted>