Split RegexHighlighters matches per requested buffer ranges

When a region calls the regex highlighter, it is incorrect to share
the regex cache as it means we can get matches that span multiple
regions.

Fixes #3041

src/highlighters.cc

@@ -333,7 +333,8 @@ private:
         size_t m_timestamp = -1;
         size_t m_regex_version = -1;
         struct RangeAndMatches { BufferRange range; MatchList matches; };
-        Vector<RangeAndMatches, MemoryDomain::Highlight> m_matches;
+        using RangeAndMatchesList = Vector<RangeAndMatches, MemoryDomain::Highlight>;
+        HashMap<BufferRange, RangeAndMatchesList, MemoryDomain::Highlight> m_matches;
     };
     BufferSideCache<Cache> m_cache;
 
@@ -377,17 +378,18 @@ private:
     const MatchList& get_matches(const Buffer& buffer, BufferRange display_range, BufferRange buffer_range)
     {
         Cache& cache = m_cache.get(buffer);
-        auto& matches = cache.m_matches;
 
         if (cache.m_regex_version != m_regex_version or
             cache.m_timestamp != buffer.timestamp() or
-            matches.size() > 1000)
+            accumulate(cache.m_matches, (size_t)0, [](size_t c, auto&& m) { return c + m.value.size(); }) > 1000)
         {
-            matches.clear();
+            cache.m_matches.clear();
             cache.m_timestamp = buffer.timestamp();
             cache.m_regex_version = m_regex_version;
         }
 
+        auto& matches = cache.m_matches[buffer_range];
+
         const LineCount line_offset = 3;
         BufferRange range{std::max<BufferCoord>(buffer_range.begin, display_range.begin.line - line_offset),
                           std::min<BufferCoord>(buffer_range.end, display_range.end.line + line_offset)};
@@ -1833,7 +1835,7 @@ public:
         const bool apply_default = default_region_it != m_regions.end();
 
         auto last_begin = (begin == regions.begin()) ?
-                             BufferCoord{0,0} : (begin-1)->end;
+                             range.begin : (begin-1)->end;
         kak_assert(begin <= end);
         for (; begin != end; ++begin)
         {

test/regression/3041-invalid-regex-highlight-accross-regions/in

@@ -0,0 +1,6 @@
+- _foo
+- bar_
+- _baz_
+
+_foo
+bar_

test/regression/3041-invalid-regex-highlight-accross-regions/rc

@@ -0,0 +1,5 @@
+add-highlighter shared/test regions
+add-highlighter shared/test/base default-region regions
+add-highlighter shared/test/base/base default-region regex _[^_]+_ 0:+b
+add-highlighter shared/test/item region '^- \K' $ ref test/base
+add-highlighter window/ ref test

test/regression/3041-invalid-regex-highlight-accross-regions/script

@@ -0,0 +1,7 @@
+ui_out '{ "jsonrpc": "2.0", "method": "set_ui_options", "params": [{}] }'
+ui_out '{ "jsonrpc": "2.0", "method": "draw", "params": [[[{ "face": { "fg": "black", "bg": "white", "attributes": [] }, "contents": "-" }, { "face": { "fg": "default", "bg": "default", "attributes": [] }, "contents": " _foo\u000a" }], [{ "face": { "fg": "default", "bg": "default", "attributes": [] }, "contents": "- bar_\u000a" }], [{ "face": { "fg": "default", "bg": "default", "attributes": [] }, "contents": "- " }, { "face": { "fg": "default", "bg": "default", "attributes": ["bold"] }, "contents": "_baz_" }, { "face": { "fg": "default", "bg": "default", "attributes": [] }, "contents": "\u000a" }], [{ "face": { "fg": "default", "bg": "default", "attributes": [] }, "contents": "\u000a" }], [{ "face": { "fg": "default", "bg": "default", "attributes": ["bold"] }, "contents": "_foo\u000a" }], [{ "face": { "fg": "default", "bg": "default", "attributes": ["bold"] }, "contents": "bar_" }, { "face": { "fg": "default", "bg": "default", "attributes": [] }, "contents": "\u000a" }]], { "fg": "default", "bg": "default", "attributes": [] }, { "fg": "blue", "bg": "default", "attributes": [] }] }'
+ui_out '{ "jsonrpc": "2.0", "method": "menu_hide", "params": [] }'
+ui_out '{ "jsonrpc": "2.0", "method": "info_hide", "params": [] }'
+ui_out '{ "jsonrpc": "2.0", "method": "draw_status", "params": [[], [{ "face": { "fg": "default", "bg": "default", "attributes": [] }, "contents": "out 1:1 " }, { "face": { "fg": "black", "bg": "yellow", "attributes": [] }, "contents": "" }, { "face": { "fg": "default", "bg": "default", "attributes": [] }, "contents": " " }, { "face": { "fg": "blue", "bg": "default", "attributes": [] }, "contents": "1 sel" }, { "face": { "fg": "default", "bg": "default", "attributes": [] }, "contents": " - client0@[kak-tests]" }], { "fg": "cyan", "bg": "default", "attributes": [] }] }'
+ui_out '{ "jsonrpc": "2.0", "method": "set_cursor", "params": ["buffer", { "line": 0, "column": 0 }] }'
+ui_out '{ "jsonrpc": "2.0", "method": "refresh", "params": [true] }'