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, 47 insertions, 0 deletions

diff --git a/mergebase/seq.go b/mergebase/seq.go
new file mode 100644
index 00000000..e7891737
--- /dev/null
+++ b/mergebase/seq.go
@@ -0,0 +1,47 @@
+package mergebase
+
+import (
+	"errors"
+	"iter"
+
+	"codeberg.org/lindenii/furgit/objectid"
+)
+
+// Seq returns the merge-base sequence. It is single-use.
+func (query *Bases) Seq() iter.Seq[objectid.ObjectID] {
+	if query.seqUsed {
+		return func(yield func(objectid.ObjectID) bool) {
+			_ = yield
+
+			if query.err == nil {
+				query.err = errors.New("mergebase: sequence already consumed")
+			}
+		}
+	}
+
+	query.seqUsed = true
+
+	return func(yield func(objectid.ObjectID) bool) {
+		if query.err != nil {
+			return
+		}
+
+		bases, err := query.compute()
+		if err != nil {
+			query.err = err
+
+			return
+		}
+
+		for _, id := range bases {
+			if !yield(id) {
+				return
+			}
+		}
+	}
+}
+
+// Err returns the terminal error, if any, once Seq has been consumed.
+func (query *Bases) Err() error {
+	return query.err
+}