Fix field floating point parsing misrepresentation

This commit fixes an issue where fields with floating points
that have zero prefixes and underscores are being parsed as
numbers.

Now those are treated as string values.

See #736

internal/field/field.go

@@ -184,9 +184,13 @@ func ValueOf(data string) Value {
 		} else if math.IsNaN(num) {
 			return Value{kind: Number, data: "NaN", num: nan}
 		}
-		return Value{kind: Number, data: data, num: num}
-	}
-	if gjson.Valid(data) {
+		// Make sure that this is a JSON compatible number.
+		// For example, "000123" and "000_123" both parse as floats but aren't
+		// really Numbers that can be represents in JSON.
+		if gjson.Valid(data) {
+			return Value{kind: Number, data: data, num: num}
+		}
+	} else if gjson.Valid(data) {
 		data = strings.TrimSpace(data)
 		r := gjson.Parse(data)
 		switch r.Type {

internal/field/field_test.go

@@ -130,5 +130,6 @@ func TestWeight(t *testing.T) {
 }
 
 func TestNumber(t *testing.T) {
-	assert.Assert(ValueOf("012").Num() == 12)
+	assert.Assert(ValueOf("12").Num() == 12)
+	assert.Assert(ValueOf("012").Num() == 0)
 }

internal/field/list_test.go

@@ -63,7 +63,7 @@ func TestList(t *testing.T) {
 	})
 	assert.Assert(names == "fellohellojellonello")
 	assert.Assert(datas == "123456789012")
-	assert.Assert(nums == 1380)
+	assert.Assert(nums == 1368)
 
 	names = ""
 	datas = ""