Fail if a sketch file is a broken symlink

Author: cmaglie

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

@@ -187,7 +187,10 @@ func (s *Sketch) supportedFiles() (paths.PathList, error) {
 
 	files, err := s.FullPath.ReadDirRecursiveFiltered(
 		paths.AndFilter(
-			filterOutBrokenLinks,
+			paths.OrFilter(
+				filterValidExtensions,
+				filterOutBrokenLinks,
+			),
 			filterOutBuildPaths,
 		),
 		paths.AndFilter(

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

@@ -37,4 +37,11 @@ func TestCompileWithBrokenSymLinks(t *testing.T) {
 		_, _, err = cli.Run("compile", "-b", "arduino:avr:uno", sketch.String())
 		require.NoError(t, err)
 	})
+
+	t.Run("SketchFileBroken", func(t *testing.T) {
+		sketch, err := paths.New("testdata", "ValidSketchWithBrokenSketchFileSymlink").Abs()
+		require.NoError(t, err)
+		_, _, err = cli.Run("compile", "-b", "arduino:avr:uno", sketch.String())
+		require.Error(t, err)
+	})
 }

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

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

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

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