On September 10, 2021 12:53 PM, Junio C Hamano wrote: >To: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> >Cc: git@xxxxxxxxxxxxxxx; Jeff King <peff@xxxxxxxx>; brian m . carlson <sandals@xxxxxxxxxxxxxxxxxxxx>; Bagas Sanjaya ><bagasdotme@xxxxxxxxx> >Subject: Re: [PATCH v2 0/8] post-v2.33 "drop support for ancient curl" follow-up > >Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> writes: > >> Version 1 of this had a really bad bug where we'd effectively make all >> supported curl versions act like 7.19.4, i.e. the oldest supported >> version except for a couple of our supported features. This is because >> most of the things checked with the "ifdef" checks are enum fields, >> not macros. So basically the "devil's advocate" Jeff King pointed out >> in [2] was already the case. Oops! > >Wow. Thanks for bothering to actually test ;-) > >Because we learned that "#ifdef CURL_SOME_FEATURE_WE_WANT" is not a generally applicable way to conditionally build for various >features and we'd need to switch on the version numbers, it is now clear (at least to me) that the central registry approach would be a >direction to go. > >> In this v2 we're instead checking LIBCURL_VERSION_NUM consistently, >> even in those cases where we are checking things that are defined via >> macros. > >Nice. > >> ++ * For each X symbol we need from curl we define our own >> ++ * GIT_CURL_HAVE_X. If multiple similar symbols with the same prefix >> ++ * were defined in the same version we pick one and check for that name. >> + * >> + * Keep any symbols in date order of when their support was >> + * introduced, oldest first, in the official version of cURL library. >> @@ git-curl-compat.h (new) >> +/** >> + * CURLOPT_TCP_KEEPALIVE was added in 7.25.0, released in March 2012. >> + */ >> -+#ifdef CURLOPT_TCP_KEEPALIVE >> ++#if LIBCURL_VERSION_NUM >= 0x071900 >> +#define GITCURL_HAVE_CURLOPT_TCP_KEEPALIVE 1 >> +#endif > >What we have in the posted patch is perfectly OK and serviceable, but this organization somewhat surprised me. > >Instead of one #if...#endif block per a feature macro, I expected to see a sequence of > > /* 7.34.0 (0x072200) - Dec 2013 */ > #if 0x072200 < VERSION > #define HAVE_FOO 1 > #define HAVE_BAR 1 > ... > #endif > > /* 7.25.0 (0x071900) - March 2012 */ > #if 0x071900 < VERSION > #define HAVE_BAZ 1 > #define HAVE_QUX 1 > ... > #endif > > >because it would make it more clear which features can now be unconditionally used when we raise the cut-off point for the oldest >supported version if we group these entries along the versions. > >Thanks. Not that it might matter much, but both NonStop platforms are now on curl 7.78.0 and we are deploying git under OpenSSL 3 this week or next. So any objections I might previously have had are now fortunately really moot. Cheers, -Randall
