Check in integration test that snapshots are listed before the index

As an exception prune is still allowed to load the index before
snapshots, as it uses exclusive locks. In case of problems with locking
it is also better to load snapshots created after loading the index, as
this will lead to a prune sanity check failure instead of a broken snapshot.

cmd/restic/integration_fuse_test.go

@@ -154,6 +154,8 @@ func TestMount(t *testing.T) {
 	}
 
 	env, cleanup := withTestEnvironment(t)
+	// must list snapshots more than once
+	env.gopts.backendTestHook = nil
 	defer cleanup()
 
 	testRunInit(t, env.gopts)
@@ -197,6 +199,8 @@ func TestMountSameTimestamps(t *testing.T) {
 	}
 
 	env, cleanup := withTestEnvironment(t)
+	// must list snapshots more than once
+	env.gopts.backendTestHook = nil
 	defer cleanup()
 
 	rtest.SetupTarTestFixture(t, env.base, filepath.Join("testdata", "repo-same-timestamps.tar.gz"))

cmd/restic/integration_helpers_test.go

@@ -198,6 +198,9 @@ func withTestEnvironment(t testing.TB) (env *testEnvironment, cleanup func()) {
 		stdout:   os.Stdout,
 		stderr:   os.Stderr,
 		extended: make(options.Options),
+
+		// replace this hook with "nil" if listing a filetype more than once is necessary
+		backendTestHook: func(r restic.Backend) (restic.Backend, error) { return newOrderedListOnceBackend(r), nil },
 	}
 
 	// always overwrite global options

cmd/restic/integration_test.go

@@ -275,6 +275,11 @@ func testRunForgetJSON(t testing.TB, gopts GlobalOptions, args ...string) {
 }
 
 func testRunPrune(t testing.TB, gopts GlobalOptions, opts PruneOptions) {
+	oldHook := gopts.backendTestHook
+	gopts.backendTestHook = func(r restic.Backend) (restic.Backend, error) { return newListOnceBackend(r), nil }
+	defer func() {
+		gopts.backendTestHook = oldHook
+	}()
 	rtest.OK(t, runPrune(opts, gopts))
 }
 
@@ -1065,6 +1070,8 @@ func TestKeyAddRemove(t *testing.T) {
 	}
 
 	env, cleanup := withTestEnvironment(t)
+	// must list keys more than once
+	env.gopts.backendTestHook = nil
 	defer cleanup()
 
 	testRunInit(t, env.gopts)
@@ -1659,6 +1666,11 @@ func TestPruneWithDamagedRepository(t *testing.T) {
 	rtest.Assert(t, len(snapshotIDs) == 1,
 		"expected one snapshot, got %v", snapshotIDs)
 
+	oldHook := env.gopts.backendTestHook
+	env.gopts.backendTestHook = func(r restic.Backend) (restic.Backend, error) { return newListOnceBackend(r), nil }
+	defer func() {
+		env.gopts.backendTestHook = oldHook
+	}()
 	// prune should fail
 	rtest.Assert(t, runPrune(pruneDefaultOptions, env.gopts) == errorPacksMissing,
 		"prune should have reported index not complete error")
@@ -1752,12 +1764,22 @@ func testEdgeCaseRepo(t *testing.T, tarfile string, optionsCheck CheckOptions, o
 type listOnceBackend struct {
 	restic.Backend
 	listedFileType map[restic.FileType]bool
+	strictOrder    bool
 }
 
 func newListOnceBackend(be restic.Backend) *listOnceBackend {
 	return &listOnceBackend{
 		Backend:        be,
 		listedFileType: make(map[restic.FileType]bool),
+		strictOrder:    false,
+	}
+}
+
+func newOrderedListOnceBackend(be restic.Backend) *listOnceBackend {
+	return &listOnceBackend{
+		Backend:        be,
+		listedFileType: make(map[restic.FileType]bool),
+		strictOrder:    true,
 	}
 }
 
@@ -1765,6 +1787,9 @@ func (be *listOnceBackend) List(ctx context.Context, t restic.FileType, fn func(
 	if t != restic.LockFile && be.listedFileType[t] {
 		return errors.Errorf("tried listing type %v the second time", t)
 	}
+	if be.strictOrder && t == restic.SnapshotFile && be.listedFileType[restic.IndexFile] {
+		return errors.Errorf("tried listing type snapshots after index")
+	}
 	be.listedFileType[t] = true
 	return be.Backend.List(ctx, t, fn)
 }