Add check for symlinks in library

check/checkconfigurations/checkconfigurations.go

@@ -806,6 +806,21 @@ var configurations = []Type{
 		ErrorModes:      nil,
 		CheckFunction:   checkfunctions.LibraryHasSubmodule,
 	},
+	{
+		ProjectType:     projecttype.Library,
+		Category:        "structure",
+		Subcategory:     "general",
+		ID:              "",
+		Brief:           "symlink",
+		Description:     "",
+		MessageTemplate: "Symlink(s) found at {{.}}. These block acceptance to the Arduino Library Manager index.",
+		DisableModes:    nil,
+		EnableModes:     []checkmode.Type{checkmode.All},
+		InfoModes:       nil,
+		WarningModes:    []checkmode.Type{checkmode.Default},
+		ErrorModes:      []checkmode.Type{checkmode.LibraryManagerSubmission, checkmode.LibraryManagerIndexed},
+		CheckFunction:   checkfunctions.LibraryContainsSymlinks,
+	},
 	{
 		ProjectType:     projecttype.Sketch,
 		Category:        "structure",

check/checkfunctions/library.go

@@ -19,6 +19,7 @@ package checkfunctions
 
 import (
 	"net/http"
+	"os"
 	"path/filepath"
 	"strings"
 
@@ -864,6 +865,33 @@ func LibraryHasSubmodule() (result checkresult.Type, output string) {
 	return checkresult.Pass, ""
 }
 
+// LibraryContainsSymlinks checks if the library folder contains symbolic links.
+func LibraryContainsSymlinks() (result checkresult.Type, output string) {
+	projectPathListing, err := checkdata.ProjectPath().ReadDirRecursive()
+	if err != nil {
+		panic(err)
+	}
+	projectPathListing.FilterOutDirs()
+
+	symlinkPaths := []string{}
+	for _, projectPathItem := range projectPathListing {
+		projectPathItemStat, err := os.Lstat(projectPathItem.String())
+		if err != nil {
+			panic(err)
+		}
+
+		if projectPathItemStat.Mode()&os.ModeSymlink != 0 {
+			symlinkPaths = append(symlinkPaths, projectPathItem.String())
+		}
+	}
+
+	if len(symlinkPaths) > 0 {
+		return checkresult.Fail, strings.Join(symlinkPaths, ", ")
+	}
+
+	return checkresult.Pass, ""
+}
+
 // spellCheckLibraryPropertiesFieldValue returns the value of the provided library.properties field with commonly misspelled words corrected.
 func spellCheckLibraryPropertiesFieldValue(fieldName string) (result checkresult.Type, output string) {
 	if checkdata.LibraryPropertiesLoadError() != nil {

check/checkfunctions/library_test.go

@@ -26,6 +26,7 @@ import (
 	"github.com/arduino/arduino-check/project/projecttype"
 	"github.com/arduino/go-paths-helper"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 var testDataPath *paths.Path
@@ -200,3 +201,27 @@ func TestLibraryHasSubmodule(t *testing.T) {
 
 	checkCheckFunction(LibraryHasSubmodule, testTables, t)
 }
+
+func TestLibraryContainsSymlinks(t *testing.T) {
+	testLibrary := "Recursive"
+	symlinkPath := testDataPath.Join(testLibrary, "test-symlink")
+	// It's probably most friendly to developers using Windows to create the symlink needed for the test on demand.
+	err := os.Symlink(testDataPath.Join(testLibrary, "library.properties").String(), symlinkPath.String())
+	require.Nil(t, err, "This test must be run as administrator on Windows to have symlink creation privilege.")
+	defer symlinkPath.RemoveAll() // clean up
+
+	testTables := []checkFunctionTestTable{
+		{"Has symlink", testLibrary, checkresult.Fail, ""},
+	}
+
+	checkCheckFunction(LibraryContainsSymlinks, testTables, t)
+
+	err = symlinkPath.RemoveAll()
+	require.Nil(t, err)
+
+	testTables = []checkFunctionTestTable{
+		{"No symlink", testLibrary, checkresult.Pass, ""},
+	}
+
+	checkCheckFunction(LibraryContainsSymlinks, testTables, t)
+}