<xloctime>: Fix time_get::do_get to parse a literal %

stl/inc/xloctime

@@ -572,6 +572,14 @@ protected:
             }
             break;
 
+        case '%':
+            if (_First == _Last || _Ctype_fac.narrow(*_First) != '%') {
+                _State |= ios_base::failbit;
+            } else {
+                ++_First;
+            }
+            break;
+
         default:
             _State |= ios_base::failbit; // unknown specifier
             break;

tests/libcxx/expected_results.txt

@@ -558,12 +558,6 @@ std/localization/locale.categories/category.time/locale.time.get/locale.time.get
 std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_weekday.pass.cpp FAIL
 std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_weekday_wide.pass.cpp FAIL
 
-# GH-6129 <xloctime>: time_get::do_get uses the wrong format for %c and %x
-# GH-6130 <xloctime>: time_get::do_get doesn't parse a literal %
-std/localization/locale.categories/category.time/locale.time.get.byname/get_one.pass.cpp FAIL
-std/localization/locale.categories/category.time/locale.time.get.byname/get_one_wide.pass.cpp FAIL
-std/localization/locale.categories/category.time/locale.time.get/locale.time.get.members/get_one.pass.cpp FAIL
-
 # GH-6134 <xloctime>: time_put::do_put does not match strftime for the %c and %r specifiers in the "C" locale
 std/localization/locale.categories/category.time/locale.time.put/locale.time.put.members/put2.pass.cpp FAIL
 
@@ -753,6 +747,14 @@ std/time/time.zone/time.zone.db/time.zone.db.tzdb/current_zone.pass.cpp FAIL
 std/localization/locale.categories/category.time/locale.time.get.byname/get_date.pass.cpp FAIL
 std/localization/locale.categories/category.time/locale.time.get.byname/get_date_wide.pass.cpp FAIL
 
+# Assertion failed: base(i) == in+sizeof(in)/sizeof(in[0])-1
+# We fixed GH-6129 "<xloctime>: time_get::do_get uses the wrong format for %c and %x",
+# which created a conflict with `#ifdef _WIN32` test code commented with:
+# `On Windows, the "%c" format lacks the leading week day`.
+# See LWG-4541 "Unclear behavior for parsing locale-dependent format".
+std/localization/locale.categories/category.time/locale.time.get.byname/get_one.pass.cpp FAIL
+std/localization/locale.categories/category.time/locale.time.get.byname/get_one_wide.pass.cpp FAIL
+
 
 # *** LIKELY STL BUGS ***
 # Not analyzed, likely STL bugs. Various assertions.

tests/std/tests/Dev11_0836436_get_time/test.cpp

@@ -114,6 +114,7 @@ void test_gh_2848();
 void test_gh_4820();
 void test_gh_4882();
 void test_gh_6129();
+void test_gh_6130();
 
 int main() {
     assert(read_hour("12 AM") == 0);
@@ -163,6 +164,7 @@ int main() {
     test_gh_4820();
     test_gh_4882();
     test_gh_6129();
+    test_gh_6130();
 }
 
 typedef istreambuf_iterator<char> Iter;
@@ -994,3 +996,22 @@ void test_gh_4882() {
         fieldValidation(testData.field, testData.hi, testData.fmt);
     }
 }
+
+void test_gh_6130() {
+    // GH-6130 <xloctime>: time_get::do_get doesn't parse a literal %
+    {
+        tm t{};
+        istringstream iss{"%"};
+        iss >> get_time(&t, "%%");
+        assert(!iss.fail());
+        assert(iss.eof());
+    }
+
+    {
+        tm t{};
+        istringstream iss{"% "};
+        iss >> get_time(&t, "%%");
+        assert(!iss.fail());
+        assert(iss.tellg() == 1);
+    }
+}