fix: issue with symlinks in directories (#24)

* fix: issue with symlinks in directories for nfpm

* test: add NoErr checks for os.Symlink calls

* test: fix assertion linting

* Ignore linter in shadowing error

glob.go

@@ -124,6 +124,14 @@ func Glob(pattern string, opts ...OptFunc) ([]string, error) { // nolint:funlen,
 		return nil, fmt.Errorf("cannot determine static prefix: %w", err)
 	}
 
+	// Check if the file is valid symlink without following it
+	// It works only for valid absolut or relative file paths, in other words, will fail for WithFs() option
+	if patternInfo, err := os.Lstat(pattern); err == nil { // nolint:govet
+		if patternInfo.Mode()&os.ModeSymlink == os.ModeSymlink {
+			return cleanFilepaths([]string{pattern}, options.prefix), nil
+		}
+	}
+
 	prefixInfo, err := fs.Stat(options.fs, prefix)
 	if errors.Is(err, fs.ErrNotExist) {
 		if !ContainsMatchers(pattern) {

glob_test.go

@@ -450,6 +450,32 @@ func TestGlob(t *testing.T) { // nolint:funlen
 			"a/b/4.txt",
 		}, matches)
 	})
+
+	t.Run("symlinks", func(t *testing.T) {
+		t.Parallel()
+		var fsPath string
+		if testFS, ok := testFs(t, []string{"./a/file"}, nil).(testfs.FS); ok {
+			fsPath = testFS.Path()
+		}
+
+		workingSymlink := filepath.Join(fsPath, "b")
+		brokenSymlink := filepath.Join(fsPath, "c")
+		err := os.Symlink("a", workingSymlink)
+		require.NoError(t, err)
+		err = os.Symlink("non-existent", brokenSymlink)
+		require.NoError(t, err)
+
+		matches, err := Glob(workingSymlink)
+		require.NoError(t, err)
+		require.Equal(t, []string{
+			workingSymlink,
+		}, matches)
+		matches, err = Glob(brokenSymlink)
+		require.NoError(t, err)
+		require.Equal(t, []string{
+			brokenSymlink,
+		}, matches)
+	})
 }
 
 func TestQuoteMeta(t *testing.T) {