sourcegraph: fix wrong git config

Turns out git config doesn't support "_" in the keys.

https://git-scm.com/docs/git-config/2.22.0#_configuration_file

"The variable names are case-insensitive, allow only alphanumeric
characters and -, and must start with an alphabetic character."

Test plan:
New unit test

api.go

@@ -638,9 +638,9 @@ func (r *Repository) UnmarshalJSON(data []byte) error {
 	// Sourcegraph indexserver doesn't set repo.Rank, so we set it here. Setting it
 	// on read instead of during indexing allows us to avoid a complete reindex.
 	//
-	// Prefer "latest_commit_date" over "priority" for ranking. We keep priority for
+	// Prefer "latestCommitDate" over "priority" for ranking. We keep priority for
 	// backwards compatibility.
-	if _, ok := repo.RawConfig["latest_commit_date"]; ok {
+	if _, ok := repo.RawConfig["latestCommitDate"]; ok {
 		// We use the number of months since 1970 as a simple measure of repo freshness.
 		// It is monotonically increasing and stable across re-indexes and restarts.
 		r.Rank = monthsSince1970(repo.LatestCommitDate)

cmd/zoekt-sourcegraph-indexserver/index.go

@@ -122,7 +122,7 @@ func (o *indexArgs) BuildOptions() *build.Options {
 				"fork":     marshalBool(o.Fork),
 				"archived": marshalBool(o.Archived),
 				// Calculate repo rank based on the latest commit date.
-				"latest_commit_date": "1",
+				"latestCommitDate": "1",
 			},
 		},
 		IndexDir:         o.IndexDir,

cmd/zoekt-sourcegraph-indexserver/index_test.go

@@ -14,6 +14,7 @@ import (
 	"time"
 
 	"github.com/sourcegraph/log/logtest"
+	"github.com/stretchr/testify/require"
 	"google.golang.org/grpc"
 	"google.golang.org/protobuf/testing/protocmp"
 	"google.golang.org/protobuf/types/known/timestamppb"
@@ -494,7 +495,7 @@ func TestIndex(t *testing.T) {
 			"git -C $TMPDIR/test%2Frepo.git update-ref HEAD deadbeef",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.archived 0",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.fork 0",
-			"git -C $TMPDIR/test%2Frepo.git config zoekt.latest_commit_date 1",
+			"git -C $TMPDIR/test%2Frepo.git config zoekt.latestCommitDate 1",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.name test/repo",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.priority 0",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.public 0",
@@ -517,7 +518,7 @@ func TestIndex(t *testing.T) {
 			"git -C $TMPDIR/test%2Frepo.git update-ref HEAD deadbeef",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.archived 0",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.fork 0",
-			"git -C $TMPDIR/test%2Frepo.git config zoekt.latest_commit_date 1",
+			"git -C $TMPDIR/test%2Frepo.git config zoekt.latestCommitDate 1",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.name test/repo",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.priority 0",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.public 0",
@@ -549,7 +550,7 @@ func TestIndex(t *testing.T) {
 			"git -C $TMPDIR/test%2Frepo.git update-ref refs/heads/dev feebdaed",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.archived 0",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.fork 0",
-			"git -C $TMPDIR/test%2Frepo.git config zoekt.latest_commit_date 1",
+			"git -C $TMPDIR/test%2Frepo.git config zoekt.latestCommitDate 1",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.name test/repo",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.priority 0",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.public 0",
@@ -597,7 +598,7 @@ func TestIndex(t *testing.T) {
 			"git -C $TMPDIR/test%2Frepo.git update-ref refs/heads/release 12345678",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.archived 0",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.fork 0",
-			"git -C $TMPDIR/test%2Frepo.git config zoekt.latest_commit_date 1",
+			"git -C $TMPDIR/test%2Frepo.git config zoekt.latestCommitDate 1",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.name test/repo",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.priority 0",
 			"git -C $TMPDIR/test%2Frepo.git config zoekt.public 0",
@@ -685,3 +686,30 @@ func (m *mockGRPCClient) UpdateIndexStatus(ctx context.Context, in *proto.Update
 }
 
 var _ proto.ZoektConfigurationServiceClient = &mockGRPCClient{}
+
+// Tests whether we can set git config values without error.
+func TestSetZoektConfig(t *testing.T) {
+	dir := t.TempDir()
+
+	// init git dir
+	script := `mkdir repo
+cd repo
+git init -b main
+`
+	cmd := exec.Command("/bin/sh", "-euxc", script)
+	cmd.Dir = dir
+	_, err := cmd.CombinedOutput()
+	require.NoError(t, err)
+
+	var out []byte
+	c := gitIndexConfig{
+		runCmd: func(cmd *exec.Cmd) error {
+			var err error
+			out, err = cmd.CombinedOutput()
+			return err
+		},
+	}
+
+	err = setZoektConfig(context.Background(), filepath.Join(dir, "repo"), &indexArgs{}, c)
+	require.NoError(t, err, string(out))
+}

internal/e2e/e2e_rank_test.go

@@ -254,7 +254,7 @@ func indexURL(indexDir, u string) error {
 		RepositoryDescription: zoekt.Repository{
 			// Use the latest commit date to calculate the repo rank when loading the shard.
 			// This is the same setting we use in production.
-			RawConfig: map[string]string{"latest_commit_date": "1"},
+			RawConfig: map[string]string{"latestCommitDate": "1"},
 		},
 	})
 	if err != nil {