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, 24 insertions, 0 deletions

diff --git a/mergebase/query.go b/mergebase/query.go
new file mode 100644
index 00000000..e2c7e54f
--- /dev/null
+++ b/mergebase/query.go
@@ -0,0 +1,24 @@
+package mergebase
+
+import (
+	commitgraphread "codeberg.org/lindenii/furgit/format/commitgraph/read"
+	"codeberg.org/lindenii/furgit/objectid"
+	"codeberg.org/lindenii/furgit/objectstore"
+)
+
+// Query builds one single-use merge-base query over two commit roots.
+//
+// Both inputs are peeled through annotated tags before commit traversal.
+func Query(
+	store objectstore.Store,
+	graph *commitgraphread.Reader,
+	left objectid.ObjectID,
+	right objectid.ObjectID,
+) *Bases {
+	return &Bases{
+		store: store,
+		graph: graph,
+		left:  left,
+		right: right,
+	}
+}