From 1dd137815970555c34c49bdb3c2049819a178c7d Mon Sep 17 00:00:00 2001
From: Ali Mohammad Pur <ali.mpfard@gmail.com>
Date: Sat, 24 Jul 2021 12:55:04 +0430
Subject: LibRegex: Preserve the type of the match when clearing capture groups

Even though the contents are supposed to be reset, the type should stay
unchanged, as that's an assumption the engine is making.
---
 Userland/Libraries/LibRegex/RegexByteCode.cpp |  5 +++--
 Userland/Libraries/LibRegex/RegexMatch.h      | 19 +++++++++++++++++++
 2 files changed, 22 insertions(+), 2 deletions(-)

(limited to 'Userland')

diff --git a/Userland/Libraries/LibRegex/RegexByteCode.cpp b/Userland/Libraries/LibRegex/RegexByteCode.cpp
index f5869acbdb..964d403c68 100644
--- a/Userland/Libraries/LibRegex/RegexByteCode.cpp
+++ b/Userland/Libraries/LibRegex/RegexByteCode.cpp
@@ -299,7 +299,7 @@ ALWAYS_INLINE ExecutionResult OpCode_ClearCaptureGroup::execute(MatchInput const
     if (input.match_index < state.capture_group_matches.size()) {
         auto& group = state.capture_group_matches[input.match_index];
         if (id() < group.size())
-            group[id()] = {};
+            group[id()].reset();
     }
     return ExecutionResult::Continue;
 }
@@ -353,7 +353,8 @@ ALWAYS_INLINE ExecutionResult OpCode_ClearNamedCaptureGroup::execute(MatchInput
 {
     if (input.match_index < state.capture_group_matches.size()) {
         auto& group = state.named_capture_group_matches[input.match_index];
-        group.remove(name());
+        if (auto it = group.find(name()); it != group.end())
+            it->value.reset();
     }
     return ExecutionResult::Continue;
 }
diff --git a/Userland/Libraries/LibRegex/RegexMatch.h b/Userland/Libraries/LibRegex/RegexMatch.h
index 4ed5cab2f0..b6cd0e0793 100644
--- a/Userland/Libraries/LibRegex/RegexMatch.h
+++ b/Userland/Libraries/LibRegex/RegexMatch.h
@@ -101,6 +101,16 @@ public:
             [](auto const& view) { return view.length(); });
     }
 
+    RegexStringView typed_null_view()
+    {
+        auto view = m_view.visit(
+            [&]<typename T>(T const&) {
+                return RegexStringView { T {} };
+            });
+        view.set_unicode(unicode());
+        return view;
+    }
+
     RegexStringView construct_as_same(Span<u32> data, Optional<String>& optional_string_storage, Vector<u16>& optional_utf16_storage) const
     {
         auto view = m_view.visit(
@@ -417,6 +427,15 @@ public:
     {
     }
 
+    void reset()
+    {
+        view = view.typed_null_view();
+        line = 0;
+        column = 0;
+        global_offset = 0;
+        left_column = 0;
+    }
+
     RegexStringView view { nullptr };
     size_t line { 0 };
     size_t column { 0 };
-- 
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