Fix buggy handling of NaN of wrong length.

Also, account for the possibility that a test's `argc` is 0.

Fixes #307.

NEWS

@@ -2,6 +2,7 @@
  - Prefer `pg_config` over `pkg-config` for include path (#291).
  - Try to plod on if we don't know the PostgreSQL include path.
  - Fix error message when starting overlapping transactions and such (#303).
+ - Fix potential crash when "NaN" isn't 3 bytes long (#307).
 7.0.5
  - Compile fix for g++ 10: include `<limits>` (#292).
  - Cleaned up error-checking of PG results.  (#280).

src/strconv.cxx

@@ -479,8 +479,9 @@ template<typename T> inline T from_string_awful_float(std::string_view text)
   case 'n':
     // Accept "NaN," "nan," etc.
     ok =
-      ((text[1] == 'A' or text[1] == 'a') and
-       (text[2] == 'N' or text[2] == 'n') and (text[3] == '\0'));
+      (text.size() == 3 and
+       (text[1] == 'A' or text[1] == 'a') and
+       (text[2] == 'N' or text[2] == 'n'));
     result = std::numeric_limits<T>::quiet_NaN();
     break;
 

test/test_main.hxx

@@ -111,7 +111,7 @@ void create_pqxxevents(transaction_base &t)
 
 namespace
 {
-std::map<char const *, pqxx::test::testfunc> *all_tests = nullptr;
+std::map<char const *, pqxx::test::testfunc> *all_tests{nullptr};
 } // namespace
 
 
@@ -132,9 +132,9 @@ void register_test(char const name[], pqxx::test::testfunc func)
 } // namespace pqxx::test
 
 
-int main(int, char const *argv[])
+int main(int argc, char const *argv[])
 {
-  char const *const test_name = argv[1];
+  char const *const test_name{(argc > 1) ? argv[1] : nullptr};
 
   int test_count = 0;
   std::list<std::string> failed;