helpers: Limit verbose watch output for better readability

Limits the number of root groups shown in 'Watching for changes' output
to 10 maximum, with a summary message for remaining paths. This prevents
the message from becoming excessively long when watching sites with many
mount points.

Fixes gohugoio#14277

Signed-off-by: majiayu000 <1835304752@qq.com>

Author: majiayu000

helpers/path.go

@@ -137,6 +137,7 @@ func ExtractAndGroupRootPaths(in []string) []string {
 		return nil
 	}
 	const maxGroups = 5
+	const maxRootGroups = 10
 	sort.Strings(in)
 	var groups []string
 	tree := radix.New[[]string]()
@@ -186,6 +187,13 @@ LOOP:
 
 	tree.Walk(collect)
 
+	// Limit the total number of root groups to keep output manageable
+	if len(groups) > maxRootGroups {
+		remaining := len(groups) - maxRootGroups
+		groups = groups[:maxRootGroups]
+		groups = append(groups, fmt.Sprintf("... and %d more", remaining))
+	}
+
 	return groups
 }
 

helpers/path_test.go

@@ -345,19 +345,34 @@ func TestAbsPathify(t *testing.T) {
 }
 
 func TestExtractAndGroupRootPaths(t *testing.T) {
-	in := []string{
-		filepath.FromSlash("/a/b/c/d"),
-		filepath.FromSlash("/a/b/c/e"),
-		filepath.FromSlash("/a/b/e/f"),
-		filepath.FromSlash("/a/b"),
-		filepath.FromSlash("/a/b/c/b/g"),
-		filepath.FromSlash("/c/d/e"),
-	}
+	c := qt.New(t)
 
-	result := helpers.ExtractAndGroupRootPaths(in)
+	t.Run("Basic grouping", func(t *testing.T) {
+		in := []string{
+			filepath.FromSlash("/a/b/c/d"),
+			filepath.FromSlash("/a/b/c/e"),
+			filepath.FromSlash("/a/b/e/f"),
+			filepath.FromSlash("/a/b"),
+			filepath.FromSlash("/a/b/c/b/g"),
+			filepath.FromSlash("/c/d/e"),
+		}
 
-	c := qt.New(t)
-	c.Assert(result, qt.DeepEquals, []string{"/a/b/{c,e}", "/c/d/e"})
+		result := helpers.ExtractAndGroupRootPaths(in)
+		c.Assert(result, qt.DeepEquals, []string{"/a/b/{c,e}", "/c/d/e"})
+	})
+
+	t.Run("Limits number of root groups", func(t *testing.T) {
+		in := []string{}
+		// Create 15 different root paths to exceed maxRootGroups (10)
+		for i := 0; i < 15; i++ {
+			in = append(in, filepath.FromSlash(fmt.Sprintf("/path%d/subdir", i)))
+		}
+
+		result := helpers.ExtractAndGroupRootPaths(in)
+		// Should have 10 paths + 1 "... and X more" message
+		c.Assert(len(result), qt.Equals, 11)
+		c.Assert(result[10], qt.Matches, `\.\.\. and \d+ more`)
+	})
 }
 
 func BenchmarkExtractAndGroupRootPaths(b *testing.B) {