Make First accept any int

TOML and YAML handles integers differently, creating issues when using integer values from configuration or front matter in the First template function.

This currently works in YAML (parses into int), but not in TOML (parses into int64).

This commit modifies First so it accepts any int.

Fixes #551

hugolib/template.go

@@ -14,6 +14,7 @@ import (
 	"strings"
 
 	"github.com/eknkc/amber"
+	"github.com/spf13/cast"
 	"github.com/spf13/hugo/helpers"
 	jww "github.com/spf13/jwalterweatherman"
 )
@@ -167,8 +168,15 @@ func In(l interface{}, v interface{}) bool {
 
 // First is exposed to templates, to iterate over the first N items in a
 // rangeable list.
-func First(limit int, seq interface{}) (interface{}, error) {
-	if limit < 1 {
+func First(limit interface{}, seq interface{}) (interface{}, error) {
+
+	limitv, err := cast.ToIntE(limit)
+
+	if err != nil {
+		return nil, err
+	}
+
+	if limitv < 1 {
 		return nil, errors.New("can't return negative/empty count of items from sequence")
 	}
 
@@ -189,10 +197,10 @@ func First(limit int, seq interface{}) (interface{}, error) {
 	default:
 		return nil, errors.New("can't iterate over " + reflect.ValueOf(seq).Type().String())
 	}
-	if limit > seqv.Len() {
-		limit = seqv.Len()
+	if limitv > seqv.Len() {
+		limitv = seqv.Len()
 	}
-	return seqv.Slice(0, limit).Interface(), nil
+	return seqv.Slice(0, limitv).Interface(), nil
 }
 
 func Where(seq, key, match interface{}) (interface{}, error) {

hugolib/template_test.go

@@ -125,21 +125,31 @@ func TestDoArithmetic(t *testing.T) {
 
 func TestFirst(t *testing.T) {
 	for i, this := range []struct {
-		count    int
+		count    interface{}
 		sequence interface{}
 		expect   interface{}
 	}{
-		{2, []string{"a", "b", "c"}, []string{"a", "b"}},
-		{3, []string{"a", "b"}, []string{"a", "b"}},
-		{2, []int{100, 200, 300}, []int{100, 200}},
+		{int(2), []string{"a", "b", "c"}, []string{"a", "b"}},
+		{int32(3), []string{"a", "b"}, []string{"a", "b"}},
+		{int64(2), []int{100, 200, 300}, []int{100, 200}},
+		{100, []int{100, 200}, []int{100, 200}},
+		{"1", []int{100, 200, 300}, []int{100}},
+		{int64(-1), []int{100, 200, 300}, false},
+		{"noint", []int{100, 200, 300}, false},
 	} {
 		results, err := First(this.count, this.sequence)
-		if err != nil {
-			t.Errorf("[%d] failed: %s", i, err)
-			continue
-		}
-		if !reflect.DeepEqual(results, this.expect) {
-			t.Errorf("[%d] First %d items, got %v but expected %v", i, this.count, results, this.expect)
+		if b, ok := this.expect.(bool); ok && !b {
+			if err == nil {
+				t.Errorf("[%d] First didn't return an expected error")
+			}
+		} else {
+			if err != nil {
+				t.Errorf("[%d] failed: %s", i, err)
+				continue
+			}
+			if !reflect.DeepEqual(results, this.expect) {
+				t.Errorf("[%d] First %d items, got %v but expected %v", i, this.count, results, this.expect)
+			}
 		}
 	}
 }