Do not fail if a non-sketch file is a broken symlink

Author: cmaglie

Diff for: internal/arduino/sketch/sketch.go

@@ -20,6 +20,7 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
+	"io/fs"
 	"sort"
 	"strings"
 
@@ -169,8 +170,26 @@ func (s *Sketch) supportedFiles() (paths.PathList, error) {
 		return !p.Join("build.options.json").Exist()
 	}
 
+	filterOutBrokenLinks := func(p *paths.Path) (res bool) {
+		if stat, err := p.LStat(); err != nil {
+			return false
+		} else if stat.Mode()&fs.ModeSymlink != fs.ModeSymlink {
+			// not a symlink, accept
+			return true
+		} else if target := p.Clone(); target.FollowSymLink() != nil {
+			// failed to follow symlink -> do not accept
+			return false
+		} else {
+			// accept only valid symlinks
+			return target.Exist()
+		}
+	}
+
 	files, err := s.FullPath.ReadDirRecursiveFiltered(
-		filterOutBuildPaths,
+		paths.AndFilter(
+			filterOutBrokenLinks,
+			filterOutBuildPaths,
+		),
 		paths.AndFilter(
 			paths.FilterOutPrefixes("."),
 			filterValidExtensions,

Diff for: internal/integrationtest/compile_4/broken_symlink_test.go

@@ -0,0 +1,40 @@
+// This file is part of arduino-cli.
+//
+// Copyright 2023 ARDUINO SA (http://www.arduino.cc/)
+//
+// This software is released under the GNU General Public License version 3,
+// which covers the main part of arduino-cli.
+// The terms of this license can be found at:
+// https://www.gnu.org/licenses/gpl-3.0.en.html
+//
+// You can be released from the requirements of the above licenses by purchasing
+// a commercial license. Buying such a license is mandatory if you want to
+// modify or otherwise use the software for commercial activities involving the
+// Arduino software without disclosing the source code of your own applications.
+// To purchase a commercial license, send an email to [email protected].
+
+package compile_test
+
+import (
+	"testing"
+
+	"github.com/arduino/arduino-cli/internal/integrationtest"
+	"github.com/arduino/go-paths-helper"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCompileWithBrokenSymLinks(t *testing.T) {
+	env, cli := integrationtest.CreateArduinoCLIWithEnvironment(t)
+	t.Cleanup(env.CleanUp)
+
+	// Install Arduino AVR Boards
+	_, _, err := cli.Run("core", "install", "arduino:[email protected]")
+	require.NoError(t, err)
+
+	t.Run("NonSketchFileBroken", func(t *testing.T) {
+		sketch, err := paths.New("testdata", "ValidSketchWithBrokenSymlink").Abs()
+		require.NoError(t, err)
+		_, _, err = cli.Run("compile", "-b", "arduino:avr:uno", sketch.String())
+		require.NoError(t, err)
+	})
+}

Diff for: internal/integrationtest/compile_4/testdata/ValidSketchWithBrokenSymlink/ValidSketchWithBrokenSymlink.ino

@@ -0,0 +1,2 @@
+void setup() {}
+void loop() {}

Diff for: internal/integrationtest/compile_4/testdata/ValidSketchWithBrokenSymlink/other_file

@@ -0,0 +1 @@
+broken

Diff for: internal/integrationtest/compile_4/testdata/ValidSketchWithBrokenSymlink/other_file.ino

@@ -0,0 +1 @@
+broken