From ca1617d3cd51427a59346ed777b734bd4d69dd4e Mon Sep 17 00:00:00 2001
From: Paul Masurel <paul.masurel@gmail.com>
Date: Sat, 25 Feb 2017 20:32:26 +0900
Subject: [PATCH] Fixes #91

---
 src/schema/schema.rs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/schema/schema.rs b/src/schema/schema.rs
index 8b35aff01..287ad40a0 100644
--- a/src/schema/schema.rs
+++ b/src/schema/schema.rs
@@ -12,7 +12,7 @@ use std::sync::Arc;
 use super::*;
 use std::fmt;
 
-
+const MAX_NUM_FIELDS: usize = 255;
 
 /// Tantivy has a very strict schema.
 /// You need to specify in advance whether a field is indexed or not,
@@ -94,10 +94,13 @@ impl SchemaBuilder {
     /// Finalize the creation of a `Schema`
     /// This will consume your `SchemaBuilder`
     pub fn build(self,) -> Schema {
+        if self.fields.len() > MAX_NUM_FIELDS {
+            panic!("There may be at most 255 fields.");
+        }
         Schema(Arc::new(InnerSchema {
             fields: self.fields,
             fields_map: self.fields_map,
-        })) 
+        }))
     }
 }