Re: [PATCH 1/1] remote-curl: unbreak http.extraHeader with custom allocators

From: Jeff King <peff@peff.net>
Date: Nov 6, 2019, 04:16 UTC
Message-ID: <20191106041644.GE4307@sigill.intra.peff.net>
In-Reply-To: <d47a2aa5949a5dd3a10b89d9a77ebb89af6ba57e.1572991158.git.gitgitgadget@gmail.com>

On Tue, Nov 05, 2019 at 09:59:18PM +0000, Johannes Schindelin via GitGitGadget wrote:

Show 17 quoted lines

> From: Johannes Schindelin <johannes.schindelin@gmx.de>
> 
> In 93b980e58f5 (http: use xmalloc with cURL, 2019-08-15), we started to
> ask cURL to use `xmalloc()`, and if compiled with nedmalloc, that means
> implicitly a different allocator than the system one.
> 
> Which means that all of cURL's allocations and releases now _need_ to
> use that allocator.
> 
> However, the `http_options()` function used `slist_append()` to add any
> configured extra HTTP header(s) _before_ asking cURL to use `xmalloc()`,
> and `http_cleanup()` would release them _afterwards_, i.e. in the
> presence of custom allocators, cURL would attempt to use the wrong
> allocator to release the memory.
> 
> Let's fix this by moving the initialization _before_ the
> `http_options()` function is called.

Nicely explained.

Another option would be to separate our config mechanism from curl entirely by putting the list of headers into a string_list, and then transforming it later into a curl_slist. I don't think that really buys us much, though. This is all inside http.c, so it's fairly contained. It's not like other random parts of Git are using curl's slist before calling http_init().

I did briefly grep around for other slist users, but they're all what you'd expect: code in http-push.c and remote-curl.c creating header lists while working with an active http request (so well after http_init() has been called).

> ---
>  http.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)

The patch itself looks good.

-Peff