Fix duplicate default option

Fixes #197. Don't parse default options twice when there is a short and
long option.

CHANGELOG.md

@@ -9,6 +9,7 @@ options. The project adheres to semantic versioning.
 
 * Only search for a C++ compiler in CMakeLists.txt.
 * Allow for exceptions to be disabled.
+* Fix duplicate default options when there is a short and long option.
 
 ## 2.2
 

include/cxxopts.hpp

@@ -1086,15 +1086,23 @@ namespace cxxopts
     parse_default(std::shared_ptr<const OptionDetails> details)
     {
       ensure_value(details);
+      m_default = true;
       m_value->parse();
     }
 
     size_t
-    count() const
+    count() const noexcept
     {
       return m_count;
     }
 
+    // TODO: maybe default options should count towards the number of arguments
+    bool
+    has_default() const noexcept
+    {
+      return m_default;
+    }
+
     template <typename T>
     const T&
     as() const
@@ -1126,6 +1134,7 @@ namespace cxxopts
 
     std::shared_ptr<Value> m_value;
     size_t m_count = 0;
+    bool m_default = false;
   };
 
   class KeyValue
@@ -1989,7 +1998,7 @@ ParseResult::parse(int& argc, char**& argv)
 
     auto& store = m_results[detail];
 
-    if(!store.count() && value.has_default()){
+    if(value.has_default() && !store.count() && !store.has_default()){
       parse_default(detail);
     }
   }

test/options.cpp

@@ -315,8 +315,10 @@ TEST_CASE("Default values", "[default]")
 {
   cxxopts::Options options("defaults", "has defaults");
   options.add_options()
-    ("default", "Has implicit", cxxopts::value<int>()
-      ->default_value("42"));
+    ("default", "Has implicit", cxxopts::value<int>()->default_value("42"))
+    ("v,vector", "Default vector", cxxopts::value<std::vector<int>>()
+      ->default_value("1,4"))
+    ;
 
   SECTION("Sets defaults") {
     Argv av({"implicit"});
@@ -327,6 +329,11 @@ TEST_CASE("Default values", "[default]")
     auto result = options.parse(argc, argv);
     CHECK(result.count("default") == 0);
     CHECK(result["default"].as<int>() == 42);
+
+    auto& v = result["vector"].as<std::vector<int>>();
+    REQUIRE(v.size() == 2);
+    CHECK(v[0] == 1);
+    CHECK(v[1] == 4);
   }
 
   SECTION("When values provided") {