3 files changed, 31 insertions, 0 deletions
diff --git a/apt-pkg/cachefilter-patterns.cc b/apt-pkg/cachefilter-patterns.cc
index 8c0b35de2..c6875d995 100644
--- a/apt-pkg/cachefilter-patterns.cc
+++ b/apt-pkg/cachefilter-patterns.cc
@@ -169,10 +169,36 @@ std::unique_ptr<PatternTreeParser::Node> PatternTreeParser::parsePrimary()
       return node;
    if ((node = parsePattern()) != nullptr)
       return node;
+   if ((node = parseGroup()) != nullptr)
+      return node;
 
    return nullptr;
 }
 
+std::unique_ptr<PatternTreeParser::Node> PatternTreeParser::parseGroup()
+{
+   if (sentence[state.offset] != '(')
+      return nullptr;
+
+   auto start = state.offset++;
+
+   skipSpace();
+   auto node = parse();
+   if (node == nullptr)
+      throw Error{Node{state.offset, sentence.size()},
+		  "Expected pattern after '('"};
+   skipSpace();
+
+   if (sentence[state.offset] != ')')
+      throw Error{Node{state.offset, sentence.size()},
+		  "Expected closing parenthesis"};
+
+   auto end = ++state.offset;
+   node->start = start;
+   node->end = end;
+   return node;
+}
+
 std::unique_ptr<PatternTreeParser::Node> PatternTreeParser::parseArgument()
 {
    std::unique_ptr<Node> node;
diff --git a/apt-pkg/cachefilter-patterns.h b/apt-pkg/cachefilter-patterns.h
index c6e701880..1b7e70da5 100644
--- a/apt-pkg/cachefilter-patterns.h
+++ b/apt-pkg/cachefilter-patterns.h
@@ -99,6 +99,7 @@ struct PatternTreeParser
    std::unique_ptr<Node> parseAnd();
    std::unique_ptr<Node> parseUnary();
    std::unique_ptr<Node> parsePrimary();
+   std::unique_ptr<Node> parseGroup();
    std::unique_ptr<Node> parsePattern();
    std::unique_ptr<Node> parseShortPattern();
    std::unique_ptr<Node> parseArgument();
diff --git a/test/libapt/pattern_test.cc b/test/libapt/pattern_test.cc
index d8d962758..ca77959e3 100644
--- a/test/libapt/pattern_test.cc
+++ b/test/libapt/pattern_test.cc
@@ -187,4 +187,8 @@ TEST(TreeParserTest, ParseShortPattern)
    EXPECT_PATTERN_EQ("!~F~T | ~T", "?or(?and(?not(?false), ?true), ?true)");
    EXPECT_PATTERN_EQ("~ramd64|~rall", "?or(?architecture(amd64), ?architecture(all))");
 
+   EXPECT_PATTERN_EQ("(?A|?B)?C", "?and(?or(?A, ?B), ?C)");
+   EXPECT_PATTERN_EQ("?A|?B?C", "?or(?A, ?and(?B, ?C))");
+   EXPECT_PATTERN_EQ("?A|(?B?C)", "?or(?A, ?and(?B, ?C))");
+   EXPECT_PATTERN_EQ("(?B?C)|?A", "?or(?and(?B, ?C), ?A)");
 }