Fix duplicate mount sources

Fixes #9426

hugofs/walk.go

@@ -270,7 +270,7 @@ func (w *Walkway) walk(path string, info FileMetaInfo, dirEntries []FileMetaInfo
 		meta.Path = normalizeFilename(pathMeta)
 		meta.PathWalk = pathn
 
-		if fim.IsDir() && w.isSeen(meta.Filename) {
+		if fim.IsDir() && meta.IsSymlink && w.isSeen(meta.Filename) {
 			// Prevent infinite recursion
 			// Possible cyclic reference
 			meta.SkipDir = true

hugofs/walk_test.go

@@ -81,14 +81,12 @@ func TestWalkRootMappingFs(t *testing.T) {
 	}
 
 	c.Run("Basic", func(c *qt.C) {
-
 		bfs := prepare(c)
 
 		names, err := collectFilenames(bfs, "", "")
 
 		c.Assert(err, qt.IsNil)
 		c.Assert(names, qt.DeepEquals, []string{"a/test.txt", "b/test.txt", "c/test.txt"})
-
 	})
 
 	c.Run("Para", func(c *qt.C) {
@@ -112,12 +110,10 @@ func TestWalkRootMappingFs(t *testing.T) {
 					return errors.New("fail")
 				}
 				return nil
-
 			})
 		}
 
 		c.Assert(r.Wait(), qt.IsNil)
-
 	})
 }
 
@@ -169,7 +165,7 @@ func TestWalkSymbolicLink(t *testing.T) {
 		names, err := collectFilenames(fs, workDir, workDir)
 		c.Assert(err, qt.IsNil)
 
-		c.Assert(names, qt.DeepEquals, []string{"blog/real/sub/a.txt", "docs/b.txt"})
+		c.Assert(names, qt.DeepEquals, []string{"blog/real/sub/a.txt", "blog/symlinked/sub/a.txt", "docs/b.txt"})
 	})
 
 	t.Run("BasePath Fs", func(t *testing.T) {