Verify releases use original Git objects

internal/git/source_test.go

@@ -142,3 +142,52 @@ func TestInspectTaggedSourceReportsDirtyCheckoutAndReadCommitFile(t *testing.T)
 		t.Fatalf("dirty status = %q", source.Status)
 	}
 }
+
+func TestCommittedReadsIgnoreReplacementObjects(t *testing.T) {
+	for _, kind := range []string{"commit", "tree", "blob"} {
+		t.Run(kind, func(t *testing.T) {
+			fixture := newRemoteFixture(t)
+			original := map[string]string{
+				"commit": fixture.commit,
+				"tree":   gitText(t, fixture.work, "rev-parse", "HEAD^{tree}"),
+				"blob":   gitText(t, fixture.work, "rev-parse", "HEAD:source.txt"),
+			}
+			writeRepoFile(t, fixture.work, "source.txt", "replacement")
+			gitRun(t, fixture.work, "add", "source.txt")
+			gitRun(t, fixture.work, "commit", "-m", "Replacement")
+			replacement := map[string]string{
+				"commit": gitText(t, fixture.work, "rev-parse", "HEAD"),
+				"tree":   gitText(t, fixture.work, "rev-parse", "HEAD^{tree}"),
+				"blob":   gitText(t, fixture.work, "rev-parse", "HEAD:source.txt"),
+			}
+			gitRun(t, fixture.work, "reset", "--hard", fixture.commit)
+			gitRun(t, fixture.work, "replace", original[kind], replacement[kind])
+
+			content, err := ReadCommitFile(t.Context(), fixture.work, fixture.commit, "source.txt")
+			if err != nil || string(content) != "candidate" {
+				t.Fatalf("committed content = %q, error = %v", content, err)
+			}
+			entries, err := ReadTree(t.Context(), fixture.work, fixture.commit)
+			if err != nil {
+				t.Fatal(err)
+			}
+			var object string
+			for _, entry := range entries {
+				if entry.Path == "source.txt" {
+					object = entry.ObjectID
+				}
+			}
+			if object != original["blob"] {
+				t.Fatalf("tree blob = %q, want %q", object, original["blob"])
+			}
+			reader := NewBlobReader(t.Context(), fixture.work)
+			content, err = reader.Read(t.Context(), object)
+			if err != nil || string(content) != "candidate" {
+				t.Fatalf("batch content = %q, error = %v", content, err)
+			}
+			if err := reader.Close(); err != nil {
+				t.Fatal(err)
+			}
+		})
+	}
+}