Remove symlink, not target, in FileOp.Rm.

client/client_test.go

@@ -139,6 +139,7 @@ func TestIntegration(t *testing.T) {
 		testPullZstdImage,
 		testMergeOp,
 		testMergeOpCache,
+		testRmSymlink,
 	}, mirrors)
 
 	integration.Run(t, []integration.Test{
@@ -3824,6 +3825,41 @@ func testSourceMapFromRef(t *testing.T, sb integration.Sandbox) {
 	require.Equal(t, int32(1), srcs[0].Ranges[0].Start.Character)
 }
 
+func testRmSymlink(t *testing.T, sb integration.Sandbox) {
+	c, err := New(sb.Context(), sb.Address())
+	require.NoError(t, err)
+	defer c.Close()
+
+	// Test that if FileOp.Rm is called on a symlink, then
+	// the symlink is removed rather than the target
+	mnt := llb.Image("alpine").
+		Run(llb.Shlex("touch /mnt/target")).
+		AddMount("/mnt", llb.Scratch())
+
+	mnt = llb.Image("alpine").
+		Run(llb.Shlex("ln -s target /mnt/link")).
+		AddMount("/mnt", mnt)
+
+	def, err := mnt.File(llb.Rm("link")).Marshal(sb.Context())
+	require.NoError(t, err)
+
+	destDir, err := ioutil.TempDir("", "buildkit")
+	require.NoError(t, err)
+	defer os.RemoveAll(destDir)
+
+	_, err = c.Solve(sb.Context(), def, SolveOpt{
+		Exports: []ExportEntry{
+			{
+				Type:      ExporterLocal,
+				OutputDir: destDir,
+			},
+		},
+	}, nil)
+	require.NoError(t, err)
+
+	require.NoError(t, fstest.CheckDirectoryEqualWithApplier(destDir, fstest.CreateFile("target", nil, 0644)))
+}
+
 func testProxyEnv(t *testing.T, sb integration.Sandbox) {
 	c, err := New(sb.Context(), sb.Address())
 	require.NoError(t, err)

solver/llbsolver/file/backend.go

@@ -146,10 +146,16 @@ func rm(ctx context.Context, d string, action pb.FileActionRm) error {
 }
 
 func rmPath(root, src string, allowNotFound bool) error {
-	p, err := fs.RootPath(root, filepath.Join("/", src))
+	src = filepath.Clean(src)
+	dir, base := filepath.Split(src)
+	if base == "" {
+		return errors.New("rmPath: invalid empty path")
+	}
+	dir, err := fs.RootPath(root, filepath.Join("/", dir))
 	if err != nil {
 		return err
 	}
+	p := filepath.Join(dir, base)
 
 	if err := os.RemoveAll(p); err != nil {
 		if errors.Is(err, os.ErrNotExist) && allowNotFound {

solver/pb/caps.go

@@ -57,6 +57,7 @@ const (
 	CapFileBase                       apicaps.CapID = "file.base"
 	CapFileRmWildcard                 apicaps.CapID = "file.rm.wildcard"
 	CapFileCopyIncludeExcludePatterns apicaps.CapID = "file.copy.includeexcludepatterns"
+	CapFileRmNoFollowSymlink          apicaps.CapID = "file.rm.nofollowsymlink"
 
 	CapConstraints apicaps.CapID = "constraints"
 	CapPlatform    apicaps.CapID = "platform"
@@ -328,6 +329,12 @@ func init() {
 		Status:  apicaps.CapStatusExperimental,
 	})
 
+	Caps.Init(apicaps.Cap{
+		ID:      CapFileRmNoFollowSymlink,
+		Enabled: true,
+		Status:  apicaps.CapStatusExperimental,
+	})
+
 	Caps.Init(apicaps.Cap{
 		ID:      CapFileCopyIncludeExcludePatterns,
 		Enabled: true,