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, 45 insertions, 7 deletions

diff --git a/internal/testgit/repo_run.go b/internal/testgit/repo_run.go
index 162a0d72..448b88f0 100644
--- a/internal/testgit/repo_run.go
+++ b/internal/testgit/repo_run.go
@@ -22,6 +22,15 @@ func (testRepo *TestRepo) RunBytes(tb testing.TB, args ...string) []byte {
 	return testRepo.runBytes(tb, nil, testRepo.dir, args...)
 }
 
+// RunE executes git and returns trimmed textual output plus any command error.
+func (testRepo *TestRepo) RunE(tb testing.TB, args ...string) (string, error) {
+	tb.Helper()
+
+	out, err := testRepo.runBytesE(nil, testRepo.dir, args...)
+
+	return strings.TrimSpace(string(out)), err
+}
+
 // RunInput executes git with stdin and returns trimmed textual output.
 func (testRepo *TestRepo) RunInput(tb testing.TB, stdin []byte, args ...string) string {
 	tb.Helper()
@@ -39,19 +48,48 @@ func (testRepo *TestRepo) RunInputBytes(tb testing.TB, stdin []byte, args ...str
 
 func (testRepo *TestRepo) runBytes(tb testing.TB, stdin []byte, dir string, args ...string) []byte {
 	tb.Helper()
+
+	out, err := testRepo.runBytesE(stdin, dir, args...)
+	if err != nil {
+		tb.Fatalf("git %v failed: %v\n%s", args, err, out)
+	}
+
+	return out
+}
+
+func (testRepo *TestRepo) runBytesE(stdin []byte, dir string, args ...string) ([]byte, error) {
+	return testRepo.runBytesWithEnvNoHelper(stdin, dir, testRepo.env, args...)
+}
+
+// runBytesWithEnv executes git using the supplied environment.
+func (testRepo *TestRepo) runBytesWithEnv(
+	tb testing.TB,
+	stdin []byte,
+	dir string,
+	env []string,
+	args ...string,
+) ([]byte, error) {
+	tb.Helper()
+
+	return testRepo.runBytesWithEnvNoHelper(stdin, dir, env, args...)
+}
+
+// runBytesWithEnvNoHelper executes git using the supplied environment without
+// touching testing helper state.
+func (testRepo *TestRepo) runBytesWithEnvNoHelper(
+	stdin []byte,
+	dir string,
+	env []string,
+	args ...string,
+) ([]byte, error) {
 	//nolint:noctx
 	cmd := exec.Command("git", args...) //#nosec G204
 	cmd.Dir = dir
 
-	cmd.Env = testRepo.env
+	cmd.Env = env
 	if stdin != nil {
 		cmd.Stdin = bytes.NewReader(stdin)
 	}
 
-	out, err := cmd.CombinedOutput()
-	if err != nil {
-		tb.Fatalf("git %v failed: %v\n%s", args, err, out)
-	}
-
-	return out
+	return cmd.CombinedOutput()
 }