From a9faa7bbce963ddb894699a7cc6ea8a3876e4d9f Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Thu, 17 Dec 2015 15:15:28 +0100
Subject: [PATCH] showId: Handle empty attribute names

We should probably disallow these, but until then, we shouldn't barf
with an assertion failure.

Fixes #738.
---
 src/libexpr/nixexpr.cc | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/libexpr/nixexpr.cc b/src/libexpr/nixexpr.cc
index 35db52a13..5bc8e4202 100644
--- a/src/libexpr/nixexpr.cc
+++ b/src/libexpr/nixexpr.cc
@@ -30,8 +30,9 @@ static void showString(std::ostream & str, const string & s)
 
 static void showId(std::ostream & str, const string & s)
 {
-    assert(!s.empty());
-    if (s == "if")
+    if (s.empty())
+        str << "\"\"";
+    else if (s == "if") // FIXME: handle other keywords
         str << '"' << s << '"';
     else {
         char c = s[0];