restore: test restore only changed parts functionality

internal/restorer/restorer_test.go

@@ -10,6 +10,7 @@ import (
 	"path/filepath"
 	"runtime"
 	"strings"
+	"syscall"
 	"testing"
 	"time"
 
@@ -929,6 +930,13 @@ func TestRestorerOverwriteBehavior(t *testing.T) {
 				"dirtest/file": "content: file2\n",
 			},
 		},
+		{
+			Overwrite: OverwriteIfChanged,
+			Files: map[string]string{
+				"foo":          "content: new\n",
+				"dirtest/file": "content: file2\n",
+			},
+		},
 		{
 			Overwrite: OverwriteIfNewer,
 			Files: map[string]string{
@@ -982,3 +990,88 @@ func TestRestorerOverwriteBehavior(t *testing.T) {
 		})
 	}
 }
+
+func TestRestoreModified(t *testing.T) {
+	// overwrite files between snapshots and also change their filesize
+	snapshots := []Snapshot{
+		{
+			Nodes: map[string]Node{
+				"foo": File{Data: "content: foo\n", ModTime: time.Now()},
+				"bar": File{Data: "content: a\n", ModTime: time.Now()},
+			},
+		},
+		{
+			Nodes: map[string]Node{
+				"foo": File{Data: "content: a\n", ModTime: time.Now()},
+				"bar": File{Data: "content: bar\n", ModTime: time.Now()},
+			},
+		},
+	}
+
+	repo := repository.TestRepository(t)
+	tempdir := filepath.Join(rtest.TempDir(t), "target")
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	for _, snapshot := range snapshots {
+		sn, id := saveSnapshot(t, repo, snapshot, noopGetGenericAttributes)
+		t.Logf("snapshot saved as %v", id.Str())
+
+		res := NewRestorer(repo, sn, Options{Overwrite: OverwriteIfChanged})
+		rtest.OK(t, res.RestoreTo(ctx, tempdir))
+		n, err := res.VerifyFiles(ctx, tempdir)
+		rtest.OK(t, err)
+		rtest.Equals(t, 2, n, "unexpected number of verified files")
+	}
+}
+
+func TestRestoreIfChanged(t *testing.T) {
+	origData := "content: foo\n"
+	modData := "content: bar\n"
+	rtest.Equals(t, len(modData), len(origData), "broken testcase")
+	snapshot := Snapshot{
+		Nodes: map[string]Node{
+			"foo": File{Data: origData, ModTime: time.Now()},
+		},
+	}
+
+	repo := repository.TestRepository(t)
+	tempdir := filepath.Join(rtest.TempDir(t), "target")
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	sn, id := saveSnapshot(t, repo, snapshot, noopGetGenericAttributes)
+	t.Logf("snapshot saved as %v", id.Str())
+
+	res := NewRestorer(repo, sn, Options{})
+	rtest.OK(t, res.RestoreTo(ctx, tempdir))
+
+	// modify file but maintain size and timestamp
+	path := filepath.Join(tempdir, "foo")
+	f, err := os.OpenFile(path, os.O_RDWR, 0)
+	rtest.OK(t, err)
+	fi, err := f.Stat()
+	rtest.OK(t, err)
+	_, err = f.Write([]byte(modData))
+	rtest.OK(t, err)
+	rtest.OK(t, f.Close())
+	var utimes = [...]syscall.Timespec{
+		syscall.NsecToTimespec(fi.ModTime().UnixNano()),
+		syscall.NsecToTimespec(fi.ModTime().UnixNano()),
+	}
+	rtest.OK(t, syscall.UtimesNano(path, utimes[:]))
+
+	for _, overwrite := range []OverwriteBehavior{OverwriteIfChanged, OverwriteAlways} {
+		res = NewRestorer(repo, sn, Options{Overwrite: overwrite})
+		rtest.OK(t, res.RestoreTo(ctx, tempdir))
+		data, err := os.ReadFile(path)
+		rtest.OK(t, err)
+		if overwrite == OverwriteAlways {
+			// restore should notice the changed file content
+			rtest.Equals(t, origData, string(data), "expected original file content")
+		} else {
+			// restore should not have noticed the changed file content
+			rtest.Equals(t, modData, string(data), "expeced modified file content")
+		}
+	}
+}

internal/restorer/restorer_unix_test.go

@@ -5,6 +5,7 @@ package restorer
 
 import (
 	"context"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"syscall"
@@ -118,3 +119,34 @@ func TestRestorerProgressBar(t *testing.T) {
 		AllBytesSkipped: 0,
 	}, mock.s)
 }
+
+func TestRestorePermissions(t *testing.T) {
+	snapshot := Snapshot{
+		Nodes: map[string]Node{
+			"foo": File{Data: "content: foo\n", Mode: 0o600, ModTime: time.Now()},
+		},
+	}
+
+	repo := repository.TestRepository(t)
+	tempdir := filepath.Join(rtest.TempDir(t), "target")
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	sn, id := saveSnapshot(t, repo, snapshot, noopGetGenericAttributes)
+	t.Logf("snapshot saved as %v", id.Str())
+
+	res := NewRestorer(repo, sn, Options{})
+	rtest.OK(t, res.RestoreTo(ctx, tempdir))
+
+	for _, overwrite := range []OverwriteBehavior{OverwriteIfChanged, OverwriteAlways} {
+		// tamper with permissions
+		path := filepath.Join(tempdir, "foo")
+		rtest.OK(t, os.Chmod(path, 0o700))
+
+		res = NewRestorer(repo, sn, Options{Overwrite: overwrite})
+		rtest.OK(t, res.RestoreTo(ctx, tempdir))
+		fi, err := os.Stat(path)
+		rtest.OK(t, err)
+		rtest.Equals(t, fs.FileMode(0o600), fi.Mode().Perm(), "unexpected permissions")
+	}
+}