[libcxx-commits] [libcxx] [regex] fix uncaught exception when string is like "\\_" (PR #129348)

[A. Jiang via libcxx-commits]

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@@ -669,6 +671,21 @@ int main(int, char**)
         assert(m.position(0) == 0);
         assert(m.str(0) == s);
     }
+    {
+      std::cmatch m;
+      const char s[] = "$_se";
+      assert(std::regex_match(s, m, std::regex("\\$\\_se")));
+      assert(m.size() == 1);
+      assert(!m.prefix().matched);
+      assert(m.prefix().first == s);
+      assert(m.prefix().second == m[0].first);
+      assert(!m.suffix().matched);
+      assert(m.suffix().first == m[0].second);
+      assert(m.suffix().second == s + std::char_traits<char>::length(s));
+      assert(m.length(0) >= 0 && static_cast<size_t>(m.length(0)) == std::char_traits<char>::length(s));
+      assert(m.position(0) == 0);
+      assert(m.str(0) == s);
+    }
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frederick-vs-ja wrote:

This part seems lost when adding coverage for `wchar_t`. We should test both `char` and `wchar_t` cases.

https://github.com/llvm/llvm-project/pull/129348