fix suppressing I/O error in parse_config_file

include/boost/program_options/parsers.hpp

@@ -175,7 +175,9 @@ namespace boost { namespace program_options {
 
     /** Parse a config file.
 
-        Read from given stream.
+        Read from given stream. Errors while reading the stream are not
+        handled in any special manner. The method `bad()` on the given
+        stream can be used to check if an error has been occurred.
     */
     template<class charT>
 #if ! BOOST_WORKAROUND(__ICL, BOOST_TESTED_AT(700))
@@ -188,7 +190,8 @@ namespace boost { namespace program_options {
     /** Parse a config file.
 
         Read from file with the given name. The character type is
-        passed to the file stream.
+        passed to the file stream. An exception of type `reading_file`
+        is thrown when the file cannot be read.
     */
 #ifdef BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS
     template<class charT>

src/parsers.cpp

@@ -152,7 +152,16 @@ namespace boost { namespace program_options {
         {
             boost::throw_exception(reading_file(filename));
         }
-        return parse_config_file(strm, desc, allow_unregistered);
+
+        basic_parsed_options<charT> result
+                = parse_config_file(strm, desc, allow_unregistered);
+
+        if (strm.bad())
+        {
+            boost::throw_exception(reading_file(filename));
+        }
+
+        return result;
     }
 
     template

test/parsers_test.cpp

@@ -375,6 +375,15 @@ void test_unregistered()
     check_value(a3[1], "m1.v1", "1");
 }
 
+void test_fail_directory(const char* some_dir)
+{
+    options_description desc;
+    TEST_CHECK_THROW(
+            parse_config_file<char>(some_dir, desc),
+            reading_file,
+            "providing directory as config file must cause exception")
+}
+
 
 
 int main(int, char* av[])
@@ -383,6 +392,7 @@ int main(int, char* av[])
     test_config_file(av[1]);
     test_environment();
     test_unregistered();
+    test_fail_directory(".");
     return 0;
 }