From 57f1818d547f2f1dca38033b4e29f62d89ef80f9 Mon Sep 17 00:00:00 2001
From: Runxi Yu
Date: Thu, 5 Mar 2026 18:24:40 +0800
Subject: format/pack/ingest: Init

---
 internal/testgit/repo_pack_objects_is_thin.go | 75 +++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 internal/testgit/repo_pack_objects_is_thin.go

(limited to 'internal')

diff --git a/internal/testgit/repo_pack_objects_is_thin.go b/internal/testgit/repo_pack_objects_is_thin.go
new file mode 100644
index 00000000..afc704d1
--- /dev/null
+++ b/internal/testgit/repo_pack_objects_is_thin.go
@@ -0,0 +1,75 @@
+package testgit
+
+import (
+	"os/exec"
+	"strings"
+	"testing"
+)
+
+// PackObjectsIsThin reports whether git emits one thin pack for the given revs.
+//
+// It streams `git pack-objects --stdout --revs --thin` into `git index-pack
+// --stdin` in one scratch bare repository. A failure in index-pack due to
+// unresolved deltas is treated as confirmation that the emitted pack is thin.
+func (testRepo *TestRepo) PackObjectsIsThin(tb testing.TB, revs []string) bool {
+	tb.Helper()
+
+	scratch := NewRepo(tb, RepoOptions{ObjectFormat: testRepo.algo, Bare: true})
+
+	packArgs := []string{"pack-objects", "--stdout", "--revs", "--thin"}
+	//nolint:noctx
+	packCmd := exec.Command("git", packArgs...) //#nosec G204
+	packCmd.Dir = testRepo.dir
+	packCmd.Env = testRepo.env
+	packCmd.Stdin = strings.NewReader(strings.Join(revs, "\n") + "\n")
+	packStderr := &strings.Builder{}
+	packCmd.Stderr = packStderr
+
+	packStdout, err := packCmd.StdoutPipe()
+	if err != nil {
+		tb.Fatalf("git %v stdout pipe: %v", packArgs, err)
+	}
+
+	indexArgs := []string{"index-pack", "--stdin"}
+	//nolint:noctx
+	indexCmd := exec.Command("git", indexArgs...) //#nosec G204
+	indexCmd.Dir = scratch.dir
+	indexCmd.Env = scratch.env
+	indexCmd.Stdin = packStdout
+	indexStderr := &strings.Builder{}
+	indexCmd.Stderr = indexStderr
+
+	err = indexCmd.Start()
+	if err != nil {
+		tb.Fatalf("git %v start failed: %v", indexArgs, err)
+	}
+
+	err = packCmd.Start()
+	if err != nil {
+		_ = indexCmd.Process.Kill()
+		_ = indexCmd.Wait()
+		tb.Fatalf("git %v start failed: %v", packArgs, err)
+	}
+
+	packErr := packCmd.Wait()
+	if packErr != nil {
+		tb.Fatalf("git %v failed: %v\n%s", packArgs, packErr, packStderr.String())
+	}
+
+	indexErr := indexCmd.Wait()
+	if indexErr == nil {
+		return false
+	}
+
+	stderr := strings.ToLower(indexStderr.String())
+	if strings.Contains(stderr, "unresolved") && strings.Contains(stderr, "delta") {
+		return true
+	}
+	if strings.Contains(stderr, "missing") && strings.Contains(stderr, "base") {
+		return true
+	}
+
+	tb.Fatalf("git %v failed unexpectedly: %v\n%s", indexArgs, indexErr, indexStderr.String())
+
+	return false
+}
-- 
cgit v1.3.1-10-gc9f91