localrepo: Speed up fetches by disabling computation of forced updatespks-git-fetch-disable-show-forced-updates

By default, git-fetch(1) will compute for every reference it's about to
fetch whether the update is a forced update or a normal one. This info
is used in two different ways:

    1. To compute whether the branch update should be allowed in the
       first place. This is pointless though in the case where we ask
       git-fetch(1) to force all updates anyway.

    2. To provide information via stdout whether the reference has been
       force-updated or not. This is pointless in the case where we ask
       git-fetch(1) to be quiet.

And while this check can indeed be quite expensive and take dozens of
seconds, git-fetch(1) will still perform it even when asked to be quiet
and to force-update any references.

Skip this computation when fetching into localrepos when forcing the
update and asking Git to be quiet.

Changelog: fixed

1 files changed, 17 insertions, 0 deletions

diff --git a/internal/git/localrepo/remote.go b/internal/git/localrepo/remote.go
index 53b1ce67e..236ef3363 100644
--- a/internal/git/localrepo/remote.go
+++ b/internal/git/localrepo/remote.go
@@ -81,6 +81,11 @@ func (repo *Repo) FetchRemote(ctx context.Context, remoteName string, opts Fetch
 	commandOptions := []git.CmdOpt{
 		git.WithEnv(opts.Env...),
 		git.WithStderr(opts.Stderr),
+		git.WithConfig(git.ConfigPair{
+			// Git is so kind to point out that we asked it to not show forced updates
+			// by default, so we need to ask it not to do that.
+			Key: "advice.fetchShowForcedUpdates", Value: "false",
+		}),
 	}
 	if opts.DisableTransactions {
 		commandOptions = append(commandOptions, git.WithDisabledHooks())
@@ -135,6 +140,11 @@ func (repo *Repo) FetchInternal(
 				GitProtocol:      git.ProtocolV2,
 			},
 		),
+		git.WithConfig(git.ConfigPair{
+			// Git is so kind to point out that we asked it to not show forced updates
+			// by default, so we need to ask it not to do that.
+			Key: "advice.fetchShowForcedUpdates", Value: "false",
+		}),
 	}
 
 	if opts.DisableTransactions {
@@ -188,6 +198,13 @@ func (opts FetchOpts) buildFlags() []git.Option {
 		flags = append(flags, git.Flag{Name: "--atomic"})
 	}
 
+	// Even if we ask Git to not print any output and to force-update branches it will still
+	// compute whether branches have been force-updated only to discard that information again.
+	// Let's ask it not to given that this check can be quite expensive.
+	if !opts.Verbose && opts.Force {
+		flags = append(flags, git.Flag{Name: "--no-show-forced-updates"})
+	}
+
 	return flags
 }