Use full output of git show-ref --tags to get tags for PushUpdateAddTag (#19235)

Strangely #19038 appears to relate to an issue whereby a tag appears to
be listed in `git show-ref --tags` but then does not appear when `git
show-ref --tags -- short_name` is called.

As a solution though I propose to stop the second call as it is
unnecessary and only likely to cause problems.

I've also noticed that the tags calls are wildly inefficient and aren't using the common cat-files - so these have been added.

I've also noticed that the git commit-graph is not being written on mirroring - so I've also added writing this to the migration which should improve mirror rendering somewhat. 

Fix #19038

Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: 6543 <6543@obermui.de>

1 files changed, 21 insertions, 0 deletions

diff --git a/modules/git/repo_commitgraph.go b/modules/git/repo_commitgraph.go
new file mode 100644
index 0000000000..5549c92591
--- /dev/null
+++ b/modules/git/repo_commitgraph.go
@@ -0,0 +1,21 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package git
+
+import (
+	"context"
+	"fmt"
+)
+
+// WriteCommitGraph write commit graph to speed up repo access
+// this requires git v2.18 to be installed
+func WriteCommitGraph(ctx context.Context, repoPath string) error {
+	if CheckGitVersionAtLeast("2.18") == nil {
+		if _, err := NewCommand(ctx, "commit-graph", "write").RunInDir(repoPath); err != nil {
+			return fmt.Errorf("unable to write commit-graph for '%s' : %w", repoPath, err)
+		}
+	}
+	return nil
+}