internal/ctlog: fix empty log hash

Fixes #14

go.mod

@@ -1,6 +1,6 @@
 module filippo.io/sunlight
 
-go 1.22.0
+go 1.22.4
 
 require (
 	crawshaw.io/sqlite v0.3.3-0.20220618202545-d1964889ea3c
@@ -14,7 +14,7 @@ require (
 	github.com/google/certificate-transparency-go v1.1.7
 	github.com/prometheus/client_golang v1.18.0
 	golang.org/x/crypto v0.19.0
-	golang.org/x/mod v0.16.1-0.20240315155916-aa51b25a4485
+	golang.org/x/mod v0.19.0
 	golang.org/x/net v0.21.0
 	golang.org/x/sync v0.6.0
 	gopkg.in/yaml.v3 v3.0.1

go.sum

@@ -93,8 +93,8 @@ github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncj
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 golang.org/x/crypto v0.19.0 h1:ENy+Az/9Y1vSrlrvBSyna3PITt4tiZLf7sgCjZBX7Wo=
 golang.org/x/crypto v0.19.0/go.mod h1:Iy9bg/ha4yyC70EfRS8jz+B6ybOBKMaSxLj6P6oBDfU=
-golang.org/x/mod v0.16.1-0.20240315155916-aa51b25a4485 h1:q+SG4bdVkCi4aZRtT8t9M/gJk15iqs59Qzhm1EwPe/g=
-golang.org/x/mod v0.16.1-0.20240315155916-aa51b25a4485/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
+golang.org/x/mod v0.19.0 h1:fEdghXQSo20giMthA7cd28ZC+jts4amQ3YMXiP5oMQ8=
+golang.org/x/mod v0.19.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
 golang.org/x/net v0.21.0 h1:AQyQV4dYCvJ7vGmJyKki9+PBdyvhkSd8EIx/qb0AYv4=
 golang.org/x/net v0.21.0/go.mod h1:bIjVDfnllIU7BJ2DNgfnXvpSvtn8VRwhlsaeUTyUS44=
 golang.org/x/sync v0.6.0 h1:5BMeUDZ7vkXGfEr1x9B4bRcTH4lpkTkpdh0T/J+qjbQ=

internal/ctlog/testlog_test.go

@@ -134,8 +134,9 @@ func (tl *TestLog) CheckLog() (sthTimestamp int64) {
 	}
 
 	if c.N == 0 {
-		if c.Hash != (tlog.Hash{}) {
-			t.Error("empty log should have zero hash")
+		expected := sha256.Sum256([]byte{})
+		if c.Hash != expected {
+			t.Error("empty log should have empty string hash")
 		}
 		return
 	}