From 7380bc81b5e9942f8346b77fc63346d86e8a236f Mon Sep 17 00:00:00 2001
From: Danny Smith <danny@gorcha.org>
Date: Mon, 26 Jul 2021 01:10:09 +1000
Subject: [PATCH] Fix issue with read_dta crashing R (#600, #608)

---
 NEWS.md          | 3 +++
 src/DfReader.cpp | 5 ++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/NEWS.md b/NEWS.md
index d0a116be..20d27c43 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,8 @@
 # haven (development version)
 
+* Fix issue with `read_dta()` crashing R when StrL variables with missing values
+were present (@gorcha, #600, #608).
+
 # haven 2.4.1
 
 * Fix buglet when combining `labelled()` with identical labels.
diff --git a/src/DfReader.cpp b/src/DfReader.cpp
index 20d54563..31a6ae93 100644
--- a/src/DfReader.cpp
+++ b/src/DfReader.cpp
@@ -354,6 +354,7 @@ class DfReader {
     case READSTAT_TYPE_STRING:
     {
       cpp11::writable::strings col(output_[var_index]);
+      const char* str_value = readstat_string_value(value);
 
       if (readstat_value_is_tagged_missing(value)) {
         col[obs_index] = NA_STRING;
@@ -361,8 +362,10 @@ class DfReader {
         col[obs_index] = NA_STRING;
       } else if (readstat_value_is_system_missing(value)) {
         col[obs_index] = NA_STRING;
+      } else if (str_value == NULL) {
+        col[obs_index] = NA_STRING;
       } else {
-        col[obs_index] = cpp11::r_string(readstat_string_value(value));
+        col[obs_index] = cpp11::r_string(str_value);
       }
       break;
     }