On Tue, Nov 16, 2021 at 07:31:12PM +0100, Ævar Arnfjörð Bjarmason wrote:

As there is no date_mode_release() API function, and given the
set of current callers it probably is not worth adding one, let's
release the .strftime_fmt member that is obtained from strdup()
before the caller of show_date() is done with it.

It does feel a bit ugly to assume that we can touch strftime_fmt here,
especially since we don't even confirm that we parsed DATE_STRFTIME.
You initialize it as NULL and the current code doesn't touch it
otherwise, so there's no bug. But it would be reasonable for other date
formats to store ancillary data as a union with strftime_fmt, which
would invalidate this.

It also seems like other callers will need to do similar cleanup. E.g.,
"git -c log.date=format:foo log" has the same leak. So maybe it is worth
adding an actual cleanup function.

-Peff