Urgh I made some wrong amends and I'm too tired to separate the commits out this time

ancestor: Split out of reachability
mergebase: Add merge base routines
internal/commitquery: Add commit query context engine thingy
internal/peel: Shared tag peeling
errors: Shared object query errors
internal/testgit: Add rooted repo helpers; remove raw path access
objectstore/memory: Add in-memory object store
objectid: Add Compare helper

1 files changed, 18 insertions, 0 deletions

diff --git a/errors/missing.go b/errors/missing.go
new file mode 100644
index 00000000..3ca27583
--- /dev/null
+++ b/errors/missing.go
@@ -0,0 +1,18 @@
+package errors
+
+import (
+	"fmt"
+
+	"codeberg.org/lindenii/furgit/objectid"
+)
+
+// ObjectMissingError indicates that a referenced object is absent from the
+// repository object store.
+type ObjectMissingError struct {
+	OID objectid.ObjectID
+}
+
+// Error implements error.
+func (e *ObjectMissingError) Error() string {
+	return fmt.Sprintf("missing object %s", e.OID)
+}