On Mon, Jul 18 2022, Jeff King wrote: > On Wed, Jul 13, 2022 at 03:10:35PM +0200, Ævar Arnfjörð Bjarmason wrote: > >> There's several potential ways to fix those sort of leaks, we could >> add a "nodup" mode to "struct strvec", which would work for the cases >> where we push constant strings to it. But that wouldn't work as soon >> as we used strvec_pushf(), or otherwise needed to duplicate or create >> a string for that "struct strvec". > > Right, I think this falls down when you have mixed const/non-const > entries. You have to know which is which for strvec_clear(). Yes, that aspect of it sucks, such a caller will need to do its own bespoke free-ing. In practice I haven't really found such callers, API users tend to use one or the other. Either they're using strvec (needs free-ing) or main()'s argv (no free-ing). To the extent that that wasn't the case I figured the easiest fix for those is probably to fully convert them to strvec, the copies being trivial in the larger context... >> Let's instead make it the responsibility of the revisions API. If it's >> going to clobber elements of argv it can also free() them, which it >> will now do if instructed to do so via "free_removed_argv_elements". > > OK, I think this is a reasonable and minimal fix for the "--" problem on > its own. > > But if you went just a little further and made the option "rev should > own its own argv", then I think you can simplify life for callers even > more. They could construct a strvec themselves and then hand it off to > the rev_info, to be cleaned up when release_revisions() is called (and > of course freeing the "--" when we overwrite it in the interim, as you > do here). > > Then all of the bisect callers from the previous patch could avoid > having to deal with the strvec at all. They'd call bisect_rev_setup(), > which would internally attach the memory to rev_info. Yes, I experimented with this, and it's a solid approach. But it's a much larger change, particularly since we'd also want to update the API itself to take take "const" in the appropriate places to do it properly.
