From: Derrick Stolee Date: Tue, 12 May 2026 14:52:38 GMT Subject: Re: [PATCH v3 4/7] remote: add remote.*.negotiationRestrict config Message-ID: In-Reply-To: On 5/12/26 8:29 AM, Matthew John Cheetham wrote: > On 2026-04-22 16:25, Derrick Stolee via GitGitGadget wrote: > >> From: Derrick Stolee >> >> In a previous change, the --negotiation-restrict command-line option of >> 'git fetch' was added as a synonym of --negotiation-tips. Both of these >> options restrict the set of 'haves' the client can send as part of >> negotiation. > > s/tips/tip/ as per the previous patch comments. Not important either > way. Thanks. >> +remote..negotiationRestrict:: >> +    When negotiating with this remote during `git fetch` and `git push`, >> +    restrict the commits advertised as "have" lines to only those >> +    reachable from refs matching the given patterns.  This multi-valued >> +    config option behaves like `--negotiation-restrict` on the command >> +    line. >> ++ >> +Each value is either an exact ref name (e.g. `refs/heads/release`) or a >> +glob pattern (e.g. `refs/heads/release/*`).  The pattern syntax is the >> +same as for `--negotiation-restrict`. >> ++ >> +These config values are used as defaults for the `--negotiation-restrict` >> +command-line option.  If `--negotiation-restrict` (or its synonym >> +`--negotiation-tip`) is specified on the command line, then the config >> +values are not used. >> ++ >> +Blank values signal to ignore all previous values, allowing a reset of >> +the list from broader config scenarios. >> + >>   remote..followRemoteHEAD:: >>       How linkgit:git-fetch[1] should handle updates to `remotes//HEAD` >>       when fetching using the configured refspecs of a remote. > > > You say "during `git fetch` and `git push`", but does `push` actually > honour the new config? > > When the `push.negotiate` config is on then > `get_commons_through_negotiation()` from send-pack.c shells out to > `git fetch --negotiate-only` with one `--negotiation-tip=` arg per > ref being pushed, then the URL. This means the CLI restrict list is > always non-empty in the subprocess so in `prepare_transport()` (in the > below hunk) the `if (negotiation_restrict.nr)` arm is always taken and the new > `else if (remote->negotiation_restrict.nr)` arm is never taken. > > BUT.. reading ahead I see that patch 7 actually wires up negotiation > config for push - so my commentary here will be moot! Do we want to drop > the "and `git push`" part from this until patch 7, when it is wired up > appropriately? You're right that this documentation is premature about 'git push'. > One other suggestion: perhaps we should clarify that `push.negotiate` > needs to be set for `remote..negotiationRestrict` to be honoured > during pushes? Yes. I'll rewrite this to focus on 'git fetch'. Then in patch 7 I can add a new detail about how to make this behavior be respected in 'git push'. >>       if (deepen_relative) { >>           if (deepen_relative < 0) >>               die(_("negative depth in --deepen is not supported")); >> @@ -2749,6 +2758,10 @@ int cmd_fetch(int argc, >>           if (!remote) >>               die(_("must supply remote when using --negotiate-only")); >>           gtransport = prepare_transport(remote, 1, &filter_options); >> +        if (!gtransport->smart_options || >> +            !gtransport->smart_options->negotiation_restrict_tips) >> +            die(_("%s needs one or more %s"), "--negotiate-only", >> +                "--negotiation-restrict=*"); >>           if (gtransport->smart_options) { >>               gtransport->smart_options->acked_commits = &acked_commits; >>           } else { > > > This new condition fires whenever `gtransport->smart_options` is NULL, > i.e. the transport doesn't support smart options. Before this case was > handled three lines after this hunk by: > >   } else { >       warning(_("protocol does not support --negotiate-only, exiting")); >       result = 1; >       trace2_region_leave("fetch", "negotiate-only", the_repository); >       goto cleanup; >   } > > What happens now if a user runs --negotiate-only against a non-smart > transport is they see an odd message: > >   fatal: --negotiate-only needs one or more --negotiation-restrict=* > > ..but they may have specified --negotiation-restrict options. > > Do we instead want &&? > >      if (gtransport->smart_options && >          !gtransport->smart_options->negotiation_restrict_tips) >          die(_("%s needs one or more %s"), "--negotiate-only", >              "--negotiation-restrict=*"); You are right that we want to say "we have smart options but haven't specified restrict arguments" so we can leave the later if/else to handle the null smart_options case. But actually, I think that it would be better to reorganize the conditions altogether: if (!gtransport->smart_options) { warning(_("protocol does not support --negotiate-only, "exiting")); result = 1; trace2_region_leave("fetch", "negotiate-only", the_repository); goto cleanup; } if (!gtransport->smart_options->negotiation_restrict_tips) die(_("%s needs one or more %s"), "--negotiate-only", "--negotiation-restrict=*"); gtransport->smart_options->acked_commits = &acked_commits; This is easier to reason about: * If we don't have smart options, then skip out of the negotiation logic. * If we don't have restrict tips, then die(). * Do the negotiation logic only if the previous two conditions didn't hold. >> @@ -562,6 +564,12 @@ static int handle_config(const char *key, const char *value, >>       } else if (!strcmp(subkey, "serveroption")) { >>           return parse_transport_option(key, value, >>                             &remote->server_options); >> +    } else if (!strcmp(subkey, "negotiationrestrict")) { >> +        /* reset list on empty value. */ >> +        if (!value || !*value) >> +            string_list_clear(&remote->negotiation_restrict, 0); >> +        else >> +            string_list_append(&remote->negotiation_restrict, value); >>       } else if (!strcmp(subkey, "followremotehead")) { >>           const char *no_warn_branch; >>           if (!strcmp(value, "never")) > > > Here we use the 'empty value means reset the list' pattern, but I notice > that the `parse_transport_option()` function already supports this reset > pattern (and used by serveroption above), with a small difference: > >   if (!value) >       return config_error_nonbool(var); >   if (!*value) >       string_list_clear(transport_options, 0); > > So NULL is an error, but empty string is 'reset'. Is it worth being > consistent with other options that use `parse_transport_options`? Thanks for catching this! Let's be consistent. NULL is likely impossible in this case, but let's be consistent. It also needs to return. Thanks, -Stolee