re PR libstdc++/63775 ([C++11] Regex range with leading dash (-) not working)

PR libstdc++/63775
	* include/bits/regex_compiler.h (_Compiler<>::_M_expression_term,
	_BracketMatcher<>::_M_make_range): Throw regex_erorr on invalid range
	like [z-a]. Change _M_expression_term interface.
	* include/bits/regex_compiler.tcc (
	_Compiler<>::_M_insert_bracket_matcher,
	_Compiler<>::_M_expression_term): Rewrite bracket expression parsing.
	* testsuite/28_regex/algorithms/regex_match/cstring_bracket_01.cc:
	Add testcases and move file out of extended.

From-SVN: r217461

libstdc++-v3/ChangeLog

@@ -1,3 +1,15 @@
+2014-11-13  Tim Shen  <timshen@google.com>
+
+	PR libstdc++/63775
+	* include/bits/regex_compiler.h (_Compiler<>::_M_expression_term,
+	_BracketMatcher<>::_M_make_range): Throw regex_erorr on invalid range
+	like [z-a]. Change _M_expression_term interface.
+	* include/bits/regex_compiler.tcc (
+	_Compiler<>::_M_insert_bracket_matcher,
+	_Compiler<>::_M_expression_term): Rewrite bracket expression parsing.
+	* testsuite/28_regex/algorithms/regex_match/cstring_bracket_01.cc:
+	Add testcases and move file out of extended.
+
 2014-11-12  Jonathan Wakely  <jwakely@redhat.com>
 
 	PR libstdc++/57250

libstdc++-v3/include/bits/regex_compiler.h

@@ -118,7 +118,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       template<bool __icase, bool __collate>
 	void
-	_M_expression_term(_BracketMatcher<_TraitsT, __icase, __collate>&
+	_M_expression_term(pair<bool, _CharT>& __last_char,
+			   _BracketMatcher<_TraitsT, __icase, __collate>&
 			   __matcher);
 
       int
@@ -390,6 +391,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       void
       _M_make_range(_CharT __l, _CharT __r)
       {
+	if (__l > __r)
+	  __throw_regex_error(regex_constants::error_range);
 	_M_range_set.push_back(make_pair(_M_translator._M_transform(__l),
 					 _M_translator._M_transform(__r)));
 #ifdef _GLIBCXX_DEBUG

libstdc++-v3/include/bits/regex_compiler.tcc

@@ -415,8 +415,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     _M_insert_bracket_matcher(bool __neg)
     {
       _BracketMatcher<_TraitsT, __icase, __collate> __matcher(__neg, _M_traits);
+      pair<bool, _CharT> __last_char; // Optional<_CharT>
+      __last_char.first = false;
+      if (!(_M_flags & regex_constants::ECMAScript))
+	if (_M_try_char())
+	  {
+	    __matcher._M_add_char(_M_value[0]);
+	    __last_char.first = true;
+	    __last_char.second = _M_value[0];
+	  }
       while (!_M_match_token(_ScannerT::_S_token_bracket_end))
-	_M_expression_term(__matcher);
+	_M_expression_term(__last_char, __matcher);
       __matcher._M_ready();
       _M_stack.push(_StateSeqT(
 		      *_M_nfa,
@@ -427,7 +436,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   template<bool __icase, bool __collate>
     void
     _Compiler<_TraitsT>::
-    _M_expression_term(_BracketMatcher<_TraitsT, __icase, __collate>& __matcher)
+    _M_expression_term(pair<bool, _CharT>& __last_char,
+		       _BracketMatcher<_TraitsT, __icase, __collate>& __matcher)
     {
       if (_M_match_token(_ScannerT::_S_token_collsymbol))
 	__matcher._M_add_collating_element(_M_value);
@@ -435,27 +445,50 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	__matcher._M_add_equivalence_class(_M_value);
       else if (_M_match_token(_ScannerT::_S_token_char_class_name))
 	__matcher._M_add_character_class(_M_value, false);
-      else if (_M_try_char()) // [a
+      // POSIX doesn't permit '-' as a start-range char (say [a-z--0]),
+      // except when the '-' is the first character in the bracket expression
+      // ([--0]). ECMAScript treats all '-' after a range as a normal character.
+      // Also see above, where _M_expression_term gets called.
+      //
+      // As a result, POSIX rejects [-----], but ECMAScript doesn't.
+      // Boost (1.57.0) always uses POSIX style even in its ECMAScript syntax.
+      // Clang (3.5) always uses ECMAScript style even in its POSIX syntax.
+      //
+      // It turns out that no one reads BNFs ;)
+      else if (_M_try_char())
 	{
-	  auto __ch = _M_value[0];
+	  if (!__last_char.first)
-	  if (_M_try_char())
 	    {
-	      if (_M_value[0] == '-') // [a-
+	      if (_M_value[0] == '-'
-		{
+		  && !(_M_flags & regex_constants::ECMAScript))
-		  if (_M_try_char()) // [a-z]
+		__throw_regex_error(regex_constants::error_range);
-		    {
-		      __matcher._M_make_range(__ch, _M_value[0]);
-		      return;
-		    }
-		  // If the dash is the last character in the bracket
-		  // expression, it is not special.
-		  if (_M_scanner._M_get_token()
-		      != _ScannerT::_S_token_bracket_end)
-		    __throw_regex_error(regex_constants::error_range);
-		}
 	      __matcher._M_add_char(_M_value[0]);
+	      __last_char.first = true;
+	      __last_char.second = _M_value[0];
+	    }
+	  else
+	    {
+	      if (_M_value[0] == '-')
+		{
+		  if (_M_try_char())
+		    {
+		      __matcher._M_make_range(__last_char.second , _M_value[0]);
+		      __last_char.first = false;
+		    }
+		  else
+		    {
+		      if (_M_scanner._M_get_token()
+			  != _ScannerT::_S_token_bracket_end)
+			__throw_regex_error(regex_constants::error_range);
+		      __matcher._M_add_char(_M_value[0]);
+		    }
+		}
+	      else
+		{
+		  __matcher._M_add_char(_M_value[0]);
+		  __last_char.second = _M_value[0];
+		}
 	    }
-	  __matcher._M_add_char(__ch);
 	}
       else if (_M_match_token(_ScannerT::_S_token_quoted_class))
 	__matcher._M_add_character_class(_M_value,

libstdc++-v3/testsuite/28_regex/algorithms/regex_match/cstring_bracket_01.cc

@@ -67,9 +67,60 @@ test01()
   }
 }
 
+void
+test02()
+{
+  bool test __attribute__((unused)) = true;
+
+  try
+  {
+    std::regex re("[-----]", std::regex::extended);
+    VERIFY(false);
+  }
+  catch (const std::regex_error& e)
+  {
+    VERIFY(e.code() == std::regex_constants::error_range);
+  }
+  std::regex re("[-----]", std::regex::ECMAScript);
+}
+
+void
+test03()
+{
+  bool test __attribute__((unused)) = true;
+
+  try
+  {
+    std::regex re("[z-a]", std::regex::extended);
+    VERIFY(false);
+  }
+  catch (const std::regex_error& e)
+  {
+    VERIFY(e.code() == std::regex_constants::error_range);
+  }
+}
+
+void
+test04()
+{
+  bool test __attribute__((unused)) = true;
+
+  std::regex re("[-0-9a-z]");
+  VERIFY(regex_match_debug("-", re));
+  VERIFY(regex_match_debug("1", re));
+  VERIFY(regex_match_debug("w", re));
+  re.assign("[-0-9a-z]", regex_constants::basic);
+  VERIFY(regex_match_debug("-", re));
+  VERIFY(regex_match_debug("1", re));
+  VERIFY(regex_match_debug("w", re));
+}
+
 int
 main()
 {
   test01();
+  test02();
+  test03();
+  test04();
   return 0;
 }