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, 51 insertions, 0 deletions

diff --git a/internal/testgit/repo_commit_tree_env.go b/internal/testgit/repo_commit_tree_env.go
new file mode 100644
index 00000000..ee949b5c
--- /dev/null
+++ b/internal/testgit/repo_commit_tree_env.go
@@ -0,0 +1,51 @@
+package testgit
+
+import (
+	"slices"
+	"strings"
+	"testing"
+
+	"codeberg.org/lindenii/furgit/objectid"
+)
+
+// CommitTreeWithEnv creates one commit from a tree and message, optionally with
+// parents, using additional environment variables for the git subprocess.
+func (testRepo *TestRepo) CommitTreeWithEnv(
+	tb testing.TB,
+	extraEnv []string,
+	tree objectid.ObjectID,
+	message string,
+	parents ...objectid.ObjectID,
+) objectid.ObjectID {
+	tb.Helper()
+
+	args := make([]string, 0, 2+2*len(parents)+2)
+
+	args = append(args, "commit-tree", tree.String())
+	for _, parent := range parents {
+		args = append(args, "-p", parent.String())
+	}
+
+	args = append(args, "-m", message)
+	hex := testRepo.runWithExtraEnv(tb, extraEnv, args...)
+
+	id, err := objectid.ParseHex(testRepo.algo, hex)
+	if err != nil {
+		tb.Fatalf("parse commit-tree output %q: %v", hex, err)
+	}
+
+	return id
+}
+
+func (testRepo *TestRepo) runWithExtraEnv(tb testing.TB, extraEnv []string, args ...string) string {
+	tb.Helper()
+
+	env := slices.Concat(testRepo.env, extraEnv)
+
+	out, err := testRepo.runBytesWithEnv(tb, nil, testRepo.dir, env, args...)
+	if err != nil {
+		tb.Fatalf("git %v failed: %v\n%s", args, err, out)
+	}
+
+	return strings.TrimSpace(string(out))
+}