metrics: Fix divide by zero error

Under certain conditions, `howSimilarString` could reach a divide-by-
zero situation which causes bogus values to print in the cache potential
column of the template hints output.  This situation essentially causes
a `int(math.NaN())` value to be returned and hilarity ensues thereafter.

diff --git a/metrics/metrics.go b/metrics/metrics.go
index 9c46fdf7ee31d068a9747f85a687cc46baf8c5cd..c57b1177d12009a781710b1de0e1932ca4cab371 100644 (file)
--- a/metrics/metrics.go
+++ b/metrics/metrics.go
@@ -281,6 +281,10 @@ func howSimilarStrings(a, b string) int {
                }
        }
 
+       if common == 0 && common == len(af) {
+               return 100
+       }
+
        return int(math.Floor((float64(common) / float64(len(af)) * 100)))
 }
 

diff --git a/metrics/metrics_test.go b/metrics/metrics_test.go
index d8c3237f85a41e6b935115f0f408065205abaddd..6e799a393134cc7601f55e98526d2e62593aa2a7 100644 (file)
--- a/metrics/metrics_test.go
+++ b/metrics/metrics_test.go
@@ -43,6 +43,7 @@ func TestSimilarPercentage(t *testing.T) {
        c.Assert(howSimilar(template.HTML("Hugo Rules"), template.HTML("Hugo Rules")), qt.Equals, 100)
        c.Assert(howSimilar(map[string]any{"a": 32, "b": 33}, map[string]any{"a": 32, "b": 33}), qt.Equals, 100)
        c.Assert(howSimilar(map[string]any{"a": 32, "b": 33}, map[string]any{"a": 32, "b": 34}), qt.Equals, 0)
+       c.Assert(howSimilar("\n", ""), qt.Equals, 100)
 }
 
 type testStruct struct {