Add header and raw_header methods, update header usage methods error handling, write new and update existing unit tests

include/ss/parser.hpp

@@ -31,6 +31,9 @@ class parser {
 
     constexpr static bool ignore_empty = setup<Options...>::ignore_empty;
 
+    using header_splitter = ss::splitter<
+        ss::filter_not_t<ss::is_instance_of_multiline, Options...>>;
+
 public:
     parser(std::string file_name, std::string delim = ss::default_delimiter)
         : file_name_{std::move(file_name)}, reader_{file_name_, delim} {
@@ -161,20 +164,49 @@ public:
         return value;
     }
 
+    std::string raw_header() const {
+        assert_ignore_header_not_defined();
+        return raw_header_;
+    }
+
+    std::vector<std::string> header() {
+        assert_ignore_header_not_defined();
+        clear_error();
+
+        header_splitter splitter;
+        std::string raw_header_copy = raw_header_;
+
+        if (!strict_split(splitter, raw_header_copy)) {
+            return {};
+        }
+
+        std::vector<std::string> split_header;
+        for (const auto& [begin, end] : splitter.split_data_) {
+            split_header.emplace_back(begin, end);
+        }
+
+        return split_header;
+    }
+
     bool field_exists(const std::string& field) {
+        assert_ignore_header_not_defined();
+        clear_error();
+
         if (header_.empty()) {
             split_header_data();
         }
 
+        if (!valid()) {
+            return false;
+        }
+
         return header_index(field).has_value();
     }
 
     template <typename... Ts>
     void use_fields(const Ts&... fields_args) {
-        if constexpr (ignore_header) {
+        assert_ignore_header_not_defined();
-            handle_error_header_ignored();
+        clear_error();
-            return;
-        }
 
         if (header_.empty() && !eof()) {
             split_header_data();
@@ -491,15 +523,51 @@ private:
     // header
     ////////////////
 
+    void assert_ignore_header_not_defined() const {
+        static_assert(!ignore_header,
+                      "cannot use this method when 'ignore_header' is defined");
+    }
+
+    bool strict_split(header_splitter& splitter, std::string& header) {
+        if (header.empty()) {
+            return false;
+        }
+
+        if constexpr (throw_on_error) {
+            try {
+                splitter.split(header.data(), reader_.delim_);
+            } catch (const ss::exception& e) {
+                decorate_rethrow_no_line(e);
+            }
+        } else {
+            splitter.split(header.data(), reader_.delim_);
+            if (!splitter.valid()) {
+                handle_error_invalid_header_split(splitter);
+                return false;
+            }
+        }
+
+        return true;
+    }
+
     void split_header_data() {
-        ss::splitter<Options...> splitter;
+        header_splitter splitter;
         std::string raw_header_copy = raw_header_;
-        splitter.split(raw_header_copy.data(), reader_.delim_);
+
+        if (!strict_split(splitter, raw_header_copy)) {
+            return;
+        }
+
         for (const auto& [begin, end] : splitter.split_data_) {
             std::string field{begin, end};
+            if (field.empty()) {
+                handle_error_duplicate_header_field(field);
+                header_.clear();
+                return;
+            }
             if (std::find(header_.begin(), header_.end(), field) !=
                 header_.end()) {
-                handle_error_invalid_header(field);
+                handle_error_duplicate_header_field(field);
                 header_.clear();
                 return;
             }
@@ -594,20 +662,6 @@ private:
         }
     }
 
-    void handle_error_header_ignored() {
-        constexpr static auto error_msg =
-            ": the header row is ignored within the setup it cannot be used";
-
-        if constexpr (string_error) {
-            error_.clear();
-            error_.append(file_name_).append(error_msg);
-        } else if constexpr (throw_on_error) {
-            throw ss::exception{file_name_ + error_msg};
-        } else {
-            error_ = true;
-        }
-    }
-
     void handle_error_invalid_field(const std::string& field) {
         constexpr static auto error_msg =
             ": header does not contain given field: ";
@@ -648,14 +702,40 @@ private:
         }
     }
 
-    void handle_error_invalid_header(const std::string& field) {
+    void handle_error_invalid_header_field() {
-        constexpr static auto error_msg = "header contains duplicates: ";
+        constexpr static auto error_msg = " header contains empty field";
 
         if constexpr (string_error) {
             error_.clear();
-            error_.append(error_msg).append(error_msg);
+            error_.append(file_name_).append(error_msg);
         } else if constexpr (throw_on_error) {
-            throw ss::exception{error_msg + field};
+            throw ss::exception{error_msg};
+        } else {
+            error_ = true;
+        }
+    }
+
+    void handle_error_duplicate_header_field(const std::string& field) {
+        constexpr static auto error_msg = " header contains duplicate: ";
+
+        if constexpr (string_error) {
+            error_.clear();
+            error_.append(file_name_).append(error_msg).append(field);
+        } else if constexpr (throw_on_error) {
+            throw ss::exception{file_name_ + error_msg + field};
+        } else {
+            error_ = true;
+        }
+    }
+
+    void handle_error_invalid_header_split(const header_splitter& splitter) {
+        constexpr static auto error_msg = " failed header split: ";
+
+        if constexpr (string_error) {
+            error_.clear();
+            error_.append(file_name_)
+                .append(error_msg)
+                .append(splitter.error_msg());
         } else {
             error_ = true;
         }
@@ -671,6 +751,14 @@ private:
                                 .append(e.what())};
     }
 
+    void decorate_rethrow_no_line(const ss::exception& e) const {
+        static_assert(throw_on_error,
+                      "throw_on_error needs to be enabled to use this method");
+        throw ss::exception{std::string{file_name_}
+                                .append(": ")
+                                .append(e.what())};
+    }
+
     ////////////////
     // line reading
     ////////////////
@@ -935,7 +1023,7 @@ private:
         }
 
         std::string get_buffer() {
-            return std::string{next_line_buffer_, next_line_buffer_size_};
+            return std::string{next_line_buffer_, next_line_size_};
         }
 
         ////////////////

include/ss/setup.hpp

@@ -293,4 +293,7 @@ private:
 template <typename... Options>
 struct setup<setup<Options...>> : setup<Options...> {};
 
+template <typename... Options>
+struct setup<std::tuple<Options...>> : setup<Options...> {};
+
 } /* namespace ss */

ssp.hpp

@@ -1054,6 +1054,9 @@ private:
 template <typename... Options>
 struct setup<setup<Options...>> : setup<Options...> {};
 
+template <typename... Options>
+struct setup<std::tuple<Options...>> : setup<Options...> {};
+
 } /* namespace ss */
 
 namespace ss {
@@ -2280,6 +2283,9 @@ class parser {
 
     constexpr static bool ignore_empty = setup<Options...>::ignore_empty;
 
+    using header_splitter = ss::splitter<
+        ss::filter_not_t<ss::is_instance_of_multiline, Options...>>;
+
 public:
     parser(std::string file_name, std::string delim = ss::default_delimiter)
         : file_name_{std::move(file_name)}, reader_{file_name_, delim} {
@@ -2410,20 +2416,49 @@ public:
         return value;
     }
 
+    std::string raw_header() const {
+        assert_ignore_header_not_defined();
+        return raw_header_;
+    }
+
+    std::vector<std::string> header() {
+        assert_ignore_header_not_defined();
+        clear_error();
+
+        header_splitter splitter;
+        std::string raw_header_copy = raw_header_;
+
+        if (!strict_split(splitter, raw_header_copy)) {
+            return {};
+        }
+
+        std::vector<std::string> split_header;
+        for (const auto& [begin, end] : splitter.split_data_) {
+            split_header.emplace_back(begin, end);
+        }
+
+        return split_header;
+    }
+
     bool field_exists(const std::string& field) {
+        assert_ignore_header_not_defined();
+        clear_error();
+
         if (header_.empty()) {
             split_header_data();
         }
 
+        if (!valid()) {
+            return false;
+        }
+
         return header_index(field).has_value();
     }
 
     template <typename... Ts>
     void use_fields(const Ts&... fields_args) {
-        if constexpr (ignore_header) {
+        assert_ignore_header_not_defined();
-            handle_error_header_ignored();
+        clear_error();
-            return;
-        }
 
         if (header_.empty() && !eof()) {
             split_header_data();
@@ -2740,15 +2775,51 @@ private:
     // header
     ////////////////
 
+    void assert_ignore_header_not_defined() const {
+        static_assert(!ignore_header,
+                      "cannot use this method when 'ignore_header' is defined");
+    }
+
+    bool strict_split(header_splitter& splitter, std::string& header) {
+        if (header.empty()) {
+            return false;
+        }
+
+        if constexpr (throw_on_error) {
+            try {
+                splitter.split(header.data(), reader_.delim_);
+            } catch (const ss::exception& e) {
+                decorate_rethrow_no_line(e);
+            }
+        } else {
+            splitter.split(header.data(), reader_.delim_);
+            if (!splitter.valid()) {
+                handle_error_invalid_header_split(splitter);
+                return false;
+            }
+        }
+
+        return true;
+    }
+
     void split_header_data() {
-        ss::splitter<Options...> splitter;
+        header_splitter splitter;
         std::string raw_header_copy = raw_header_;
-        splitter.split(raw_header_copy.data(), reader_.delim_);
+
+        if (!strict_split(splitter, raw_header_copy)) {
+            return;
+        }
+
         for (const auto& [begin, end] : splitter.split_data_) {
             std::string field{begin, end};
+            if (field.empty()) {
+                handle_error_duplicate_header_field(field);
+                header_.clear();
+                return;
+            }
             if (std::find(header_.begin(), header_.end(), field) !=
                 header_.end()) {
-                handle_error_invalid_header(field);
+                handle_error_duplicate_header_field(field);
                 header_.clear();
                 return;
             }
@@ -2843,20 +2914,6 @@ private:
         }
     }
 
-    void handle_error_header_ignored() {
-        constexpr static auto error_msg =
-            ": the header row is ignored within the setup it cannot be used";
-
-        if constexpr (string_error) {
-            error_.clear();
-            error_.append(file_name_).append(error_msg);
-        } else if constexpr (throw_on_error) {
-            throw ss::exception{file_name_ + error_msg};
-        } else {
-            error_ = true;
-        }
-    }
-
     void handle_error_invalid_field(const std::string& field) {
         constexpr static auto error_msg =
             ": header does not contain given field: ";
@@ -2897,14 +2954,40 @@ private:
         }
     }
 
-    void handle_error_invalid_header(const std::string& field) {
+    void handle_error_invalid_header_field() {
-        constexpr static auto error_msg = "header contains duplicates: ";
+        constexpr static auto error_msg = " header contains empty field";
 
         if constexpr (string_error) {
             error_.clear();
-            error_.append(error_msg).append(error_msg);
+            error_.append(file_name_).append(error_msg);
         } else if constexpr (throw_on_error) {
-            throw ss::exception{error_msg + field};
+            throw ss::exception{error_msg};
+        } else {
+            error_ = true;
+        }
+    }
+
+    void handle_error_duplicate_header_field(const std::string& field) {
+        constexpr static auto error_msg = " header contains duplicate: ";
+
+        if constexpr (string_error) {
+            error_.clear();
+            error_.append(file_name_).append(error_msg).append(field);
+        } else if constexpr (throw_on_error) {
+            throw ss::exception{file_name_ + error_msg + field};
+        } else {
+            error_ = true;
+        }
+    }
+
+    void handle_error_invalid_header_split(const header_splitter& splitter) {
+        constexpr static auto error_msg = " failed header split: ";
+
+        if constexpr (string_error) {
+            error_.clear();
+            error_.append(file_name_)
+                .append(error_msg)
+                .append(splitter.error_msg());
         } else {
             error_ = true;
         }
@@ -2920,6 +3003,14 @@ private:
                                 .append(e.what())};
     }
 
+    void decorate_rethrow_no_line(const ss::exception& e) const {
+        static_assert(throw_on_error,
+                      "throw_on_error needs to be enabled to use this method");
+        throw ss::exception{std::string{file_name_}
+                                .append(": ")
+                                .append(e.what())};
+    }
+
     ////////////////
     // line reading
     ////////////////
@@ -3184,7 +3275,7 @@ private:
         }
 
         std::string get_buffer() {
-            return std::string{next_line_buffer_, next_line_buffer_size_};
+            return std::string{next_line_buffer_, next_line_size_};
         }
 
         ////////////////

test/test_helpers.hpp

@@ -145,6 +145,17 @@ struct unique_file_name {
         CHECK_FALSE(std::string{e.what()}.empty());                            \
     }
 
+#define CHECK_EQ_ARRAY(first, second)                                          \
+    {                                                                          \
+        const auto& first_ = (first);                                          \
+        const auto& second_ = (second);                                        \
+        CHECK_EQ(first_.size(), second_.size());                               \
+        for (size_t i_ = 0; i_ < std::min(first_.size(), second_.size());      \
+             ++i_) {                                                           \
+            CHECK_EQ(first_[i_], second_[i_]);                                 \
+        }                                                                      \
+    }
+
 template <typename T>
 [[maybe_unused]] std::vector<std::vector<T>> vector_combinations(
     const std::vector<T>& v, size_t n) {
@@ -166,6 +177,22 @@ template <typename T>
     return ret;
 }
 
+[[maybe_unused]] std::string merge_header(
+    const std::vector<std::string>& header,
+    const std::string& delimiter = ss::default_delimiter) {
+    std::string s;
+    if (!header.empty()) {
+        for (const auto& i : header) {
+            s.append(i);
+            s.append(delimiter);
+        }
+        for (size_t i = 0; i < delimiter.size(); ++i) {
+            s.pop_back();
+        }
+    }
+    return s;
+};
+
 [[maybe_unused]] std::string make_buffer(const std::string& file_name) {
     std::ifstream in{file_name, std::ios::binary};
     std::string tmp;

test/test_parser1.hpp

@@ -28,6 +28,7 @@ void expect_error_on_command(ss::parser<Ts...>& p,
     if (ss::setup<Ts...>::throw_on_error) {
         try {
             command();
+            FAIL("expected exception");
         } catch (const std::exception& e) {
             CHECK_FALSE(std::string{e.what()}.empty());
         }

test/test_parser1_4.cpp

@@ -9,6 +9,7 @@ struct has_type<T, std::tuple<Us...>>
 
 template <typename T, typename... Ts>
 static void test_fields(const std::string file_name, const std::vector<X>& data,
+                        const std::vector<std::string>& header,
                         const std::vector<std::string>& fields) {
     constexpr auto buffer_mode = T::BufferMode::value;
     using ErrorMode = typename T::ErrorMode;
@@ -17,9 +18,14 @@ static void test_fields(const std::string file_name, const std::vector<X>& data,
     auto [p, _] = make_parser<buffer_mode, ErrorMode>(file_name, ",");
     CHECK_FALSE(p.field_exists("Unknown"));
     p.use_fields(fields);
+
+    CHECK_EQ_ARRAY(header, p.header());
+    CHECK_EQ(merge_header(p.header(), ","), p.raw_header());
     std::vector<CaseType> i;
 
     for (const auto& a : p.template iterate<CaseType>()) {
+        CHECK_EQ_ARRAY(header, p.header());
+        CHECK_EQ(merge_header(p.header(), ","), p.raw_header());
         i.push_back(a);
     }
 
@@ -40,12 +46,12 @@ static void test_fields(const std::string file_name, const std::vector<X>& data,
 TEST_CASE_TEMPLATE("test various cases with header", T,
                    ParserOptionCombinations) {
     unique_file_name f{"various_cases_with_header"};
+    using str = std::string;
+
     constexpr static auto Int = "Int";
     constexpr static auto Dbl = "Double";
     constexpr static auto Str = "String";
-    using str = std::string;
+    const std::vector<std::string> header{Int, Dbl, Str};
-
-    std::vector<std::string> header{Int, Dbl, Str};
 
     std::vector<X> data = {{1, 2, "x"}, {3, 4, "y"},  {5, 6, "z"},
                            {7, 8, "u"}, {9, 10, "v"}, {11, 12, "w"}};
@@ -59,6 +65,8 @@ TEST_CASE_TEMPLATE("test various cases with header", T,
         std::vector<X> i;
 
         for (const auto& a : p.iterate<int, double, std::string>()) {
+            CHECK_EQ(header, p.header());
+            CHECK_EQ(merge_header(p.header(), ","), p.raw_header());
             i.emplace_back(ss::to_object<X>(a));
         }
 
@@ -71,46 +79,22 @@ TEST_CASE_TEMPLATE("test various cases with header", T,
 
         p.ignore_next();
         for (const auto& a : p.iterate<int, double, std::string>()) {
+            CHECK_EQ(header, p.header());
+            CHECK_EQ(merge_header(p.header(), ","), p.raw_header());
             i.emplace_back(ss::to_object<X>(a));
         }
 
         CHECK_EQ(i, data);
     }
 
-    {
-        ss::parser<ss::ignore_header> p{f.name, ","};
-        std::vector<X> i;
-
-        for (const auto& a : p.iterate<int, double, std::string>()) {
-            i.emplace_back(ss::to_object<X>(a));
-        }
-
-        CHECK_EQ(i, data);
-    }
-
-    {
-        ss::parser<ss::ignore_header, ss::string_error> p{f.name, ","};
-        p.use_fields(Int, Dbl, Str);
-        CHECK_FALSE(p.valid());
-    }
-
-    {
-        ss::parser<ss::ignore_header, ss::string_error> p{f.name, ","};
-        CHECK_FALSE(p.field_exists("Unknown"));
-
-        p.use_fields(Int, "Unknown");
-        CHECK_FALSE(p.valid());
-    }
-
-    {
-        ss::parser<ss::ignore_header, ss::string_error> p{f.name, ","};
-        p.use_fields(Int, Int);
-        CHECK_FALSE(p.valid());
-    }
-
     {
         ss::parser<ss::string_error> p{f.name, ","};
+        CHECK_EQ(header, p.header());
+        CHECK_EQ(merge_header(p.header(), ","), p.raw_header());
+
         p.use_fields(Int, Dbl);
+        CHECK_EQ(header, p.header());
+        CHECK_EQ(merge_header(p.header(), ","), p.raw_header());
 
         {
             auto [int_, double_] = p.get_next<int, double>();
@@ -119,6 +103,8 @@ TEST_CASE_TEMPLATE("test various cases with header", T,
         }
 
         p.use_fields(Dbl, Int);
+        CHECK_EQ(header, p.header());
+        CHECK_EQ(merge_header(p.header(), ","), p.raw_header());
 
         {
             auto [double_, int_] = p.get_next<double, int>();
@@ -163,25 +149,25 @@ TEST_CASE_TEMPLATE("test various cases with header", T,
                     template_params.append(type)
                     arg_params.append(header[type])
                 call = 'testFields<' + ', '.join(template_params) + \
-                    '>(o, d, {' + ', '.join(arg_params) + '});'
+                    '>(o, d, header, {' + ', '.join(arg_params) + '});'
                 print(call)
         */
 
-    test_fields<T, str>(o, d, {Str});
+    test_fields<T, str>(o, d, header, {Str});
-    test_fields<T, int>(o, d, {Int});
+    test_fields<T, int>(o, d, header, {Int});
-    test_fields<T, double>(o, d, {Dbl});
+    test_fields<T, double>(o, d, header, {Dbl});
-    test_fields<T, str, int>(o, d, {Str, Int});
+    test_fields<T, str, int>(o, d, header, {Str, Int});
-    test_fields<T, str, double>(o, d, {Str, Dbl});
+    test_fields<T, str, double>(o, d, header, {Str, Dbl});
-    test_fields<T, int, str>(o, d, {Int, Str});
+    test_fields<T, int, str>(o, d, header, {Int, Str});
-    test_fields<T, int, double>(o, d, {Int, Dbl});
+    test_fields<T, int, double>(o, d, header, {Int, Dbl});
-    test_fields<T, double, str>(o, d, {Dbl, Str});
+    test_fields<T, double, str>(o, d, header, {Dbl, Str});
-    test_fields<T, double, int>(o, d, {Dbl, Int});
+    test_fields<T, double, int>(o, d, header, {Dbl, Int});
-    test_fields<T, str, int, double>(o, d, {Str, Int, Dbl});
+    test_fields<T, str, int, double>(o, d, header, {Str, Int, Dbl});
-    test_fields<T, str, double, int>(o, d, {Str, Dbl, Int});
+    test_fields<T, str, double, int>(o, d, header, {Str, Dbl, Int});
-    test_fields<T, int, str, double>(o, d, {Int, Str, Dbl});
+    test_fields<T, int, str, double>(o, d, header, {Int, Str, Dbl});
-    test_fields<T, int, double, str>(o, d, {Int, Dbl, Str});
+    test_fields<T, int, double, str>(o, d, header, {Int, Dbl, Str});
-    test_fields<T, double, str, int>(o, d, {Dbl, Str, Int});
+    test_fields<T, double, str, int>(o, d, header, {Dbl, Str, Int});
-    test_fields<T, double, int, str>(o, d, {Dbl, Int, Str});
+    test_fields<T, double, int, str>(o, d, header, {Dbl, Int, Str});
 }
 
 template <typename T>
@@ -190,6 +176,17 @@ void test_invalid_fields(const std::vector<std::string>& lines,
     constexpr auto buffer_mode = T::BufferMode::value;
     using ErrorMode = typename T::ErrorMode;
 
+    auto check_header = [&lines](auto& p) {
+        if (lines.empty()) {
+            CHECK(p.header().empty());
+            CHECK_EQ(merge_header(p.header(), ","), p.raw_header());
+        } else {
+            CHECK_EQ(lines[0], merge_header(p.header()));
+            CHECK_EQ(merge_header(p.header(), ","), p.raw_header());
+        }
+        CHECK(p.valid());
+    };
+
     unique_file_name f{"invalid_fields"};
     {
         std::ofstream out{f.name};
@@ -203,6 +200,7 @@ void test_invalid_fields(const std::vector<std::string>& lines,
         auto [p, _] = make_parser<buffer_mode, ErrorMode>(f.name, ",");
         auto command = [&p = p] { p.use_fields(); };
         expect_error_on_command(p, command);
+        check_header(p);
     }
 
     {
@@ -210,6 +208,7 @@ void test_invalid_fields(const std::vector<std::string>& lines,
         auto [p, _] = make_parser<buffer_mode, ErrorMode>(f.name, ",");
         auto command = [&p = p] { p.use_fields("Unknown"); };
         expect_error_on_command(p, command);
+        check_header(p);
     }
 
     {
@@ -221,6 +220,7 @@ void test_invalid_fields(const std::vector<std::string>& lines,
         if (!fields.empty()) {
             expect_error_on_command(p, command);
         }
+        check_header(p);
     }
 
     {
@@ -230,15 +230,19 @@ void test_invalid_fields(const std::vector<std::string>& lines,
             p.use_fields(fields.at(0));
             p.template get_next<std::string, std::string>();
         };
+        check_header(p);
+
         if (!fields.empty()) {
             expect_error_on_command(p, command);
         }
+        check_header(p);
     }
 
     {
         // Invalid header
         auto [p, _] = make_parser<buffer_mode, ErrorMode>(f.name, ",");
         auto command = [&p = p, &fields = fields] { p.use_fields(fields); };
+        check_header(p);
 
         if (!fields.empty()) {
             // Pass if there are no duplicates, fail otherwise
@@ -255,6 +259,7 @@ void test_invalid_fields(const std::vector<std::string>& lines,
                 }
             }
         }
+        check_header(p);
     }
 }
 
@@ -289,7 +294,7 @@ TEST_CASE_TEMPLATE("test invalid rows with header", T,
     constexpr auto buffer_mode = T::BufferMode::value;
     using ErrorMode = typename T::ErrorMode;
 
-    unique_file_name f{"invalid rows with header"};
+    unique_file_name f{"invalid_rows_with_header"};
     {
         std::ofstream out{f.name};
         out << "Int,String,Double" << std::endl;
@@ -301,8 +306,12 @@ TEST_CASE_TEMPLATE("test invalid rows with header", T,
         out << "six,line6,10.11" << std::endl;
     }
 
+    std::vector<std::string> header = {"Int", "String", "Double"};
+
     {
         auto [p, _] = make_parser<buffer_mode, ErrorMode>(f.name);
+        CHECK_EQ_ARRAY(header, p.header());
+        CHECK_EQ(merge_header(p.header()), p.raw_header());
 
         p.use_fields("Int", "String", "Double");
         using data = std::tuple<int, std::string, double>;
@@ -325,10 +334,14 @@ TEST_CASE_TEMPLATE("test invalid rows with header", T,
                                       {3, "line3", 67.8},
                                       {5, "line5", 9.10}};
         CHECK_EQ(i, expected);
+        CHECK_EQ_ARRAY(header, p.header());
+        CHECK_EQ(merge_header(p.header()), p.raw_header());
     }
 
     {
         auto [p, _] = make_parser<buffer_mode, ErrorMode>(f.name);
+        CHECK_EQ_ARRAY(header, p.header());
+        CHECK_EQ(merge_header(p.header()), p.raw_header());
 
         p.use_fields("Double", "Int");
         using data = std::tuple<double, int>;
@@ -349,10 +362,14 @@ TEST_CASE_TEMPLATE("test invalid rows with header", T,
 
         std::vector<data> expected = {{2.34, 1}, {67.8, 3}, {9.10, 5}};
         CHECK_EQ(i, expected);
+        CHECK_EQ_ARRAY(header, p.header());
+        CHECK_EQ(merge_header(p.header()), p.raw_header());
     }
 
     {
         auto [p, _] = make_parser<buffer_mode, ErrorMode>(f.name);
+        CHECK_EQ_ARRAY(header, p.header());
+        CHECK_EQ(merge_header(p.header()), p.raw_header());
 
         p.use_fields("String", "Double");
         using data = std::tuple<std::string, double>;
@@ -376,6 +393,92 @@ TEST_CASE_TEMPLATE("test invalid rows with header", T,
                                       {"line5", 9.10},
                                       {"line6", 10.11}};
         CHECK_EQ(i, expected);
+        CHECK_EQ_ARRAY(header, p.header());
+        CHECK_EQ(merge_header(p.header()), p.raw_header());
+    }
+}
+
+TEST_CASE_TEMPLATE("test invalid header", T, ParserOptionCombinations) {
+    constexpr auto buffer_mode = T::BufferMode::value;
+    using ErrorMode = typename T::ErrorMode;
+
+    unique_file_name f{"invalid_header"};
+
+    // Empty header
+    {
+        std::ofstream out{f.name};
+        out << "" << std::endl;
+        out << "1" << std::endl;
+    }
+
+    {
+        auto [p, _] = make_parser<buffer_mode, ErrorMode>(f.name);
+        CHECK(p.header().empty());
+        CHECK_EQ(merge_header(p.header()), p.raw_header());
+        CHECK(p.valid());
+    }
+
+    // Unterminated quote in header
+    {
+        std::ofstream out{f.name};
+        out << "\"Int" << std::endl;
+        out << "1" << std::endl;
+    }
+
+    {
+        auto [p, _] =
+            make_parser<buffer_mode, ErrorMode, ss::quote<'"'>>(f.name);
+        auto command = [&p = p] { p.header(); };
+        expect_error_on_command(p, command);
+        CHECK_EQ(p.raw_header(), "\"Int");
+    }
+
+    {
+        auto [p, _] =
+            make_parser<buffer_mode, ErrorMode, ss::quote<'"'>, ss::multiline>(
+                f.name);
+        auto command = [&p = p] { p.header(); };
+        expect_error_on_command(p, command);
+        CHECK_EQ(p.raw_header(), "\"Int");
+    }
+
+    {
+        auto [p, _] = make_parser<buffer_mode, ErrorMode, ss::quote<'"'>,
+                                  ss::escape<'\\'>, ss::multiline>(f.name);
+        auto command = [&p = p] { p.header(); };
+        expect_error_on_command(p, command);
+        CHECK_EQ(p.raw_header(), "\"Int");
+    }
+
+    // Unterminated escape in header
+    {
+        std::ofstream out{f.name};
+        out << "Int\\" << std::endl;
+        out << "1" << std::endl;
+    }
+
+    {
+        auto [p, _] =
+            make_parser<buffer_mode, ErrorMode, ss::escape<'\\'>>(f.name);
+        auto command = [&p = p] { p.header(); };
+        expect_error_on_command(p, command);
+        CHECK_EQ(p.raw_header(), "Int\\");
+    }
+
+    {
+        auto [p, _] = make_parser<buffer_mode, ErrorMode, ss::escape<'\\'>,
+                                  ss::multiline>(f.name);
+        auto command = [&p = p] { p.header(); };
+        expect_error_on_command(p, command);
+        CHECK_EQ(p.raw_header(), "Int\\");
+    }
+
+    {
+        auto [p, _] = make_parser<buffer_mode, ErrorMode, ss::escape<'\\'>,
+                                  ss::quote<'"'>, ss::multiline>(f.name);
+        auto command = [&p = p] { p.header(); };
+        expect_error_on_command(p, command);
+        CHECK_EQ(p.raw_header(), "Int\\");
     }
 }
 

test/test_parser2.hpp

@@ -1,13 +1,7 @@
 #include "test_helpers.hpp"
-#include <algorithm>
-#include <filesystem>
 #include <fstream>
-#include <iomanip>
 #include <iostream>
-#include <regex>
 #include <ss/parser.hpp>
-#include <sstream>
-#include <unordered_map>
 #include <unordered_set>
 
 #ifndef SEGMENT_NAME
@@ -333,8 +327,10 @@ void test_data_combinations(const std::vector<column>& input_data,
         field_header.push_back(field{el.header});
     }
 
+    std::string header_line;
     if (include_header) {
         auto header_data = generate_csv_data<Ts...>(field_header, delim);
+        header_line = merge_header(header_data, delim);
         if (input_data.size() == 0 && rand() % 10 == 0) {
             write_to_file(header_data, delim, f.name, false);
         } else {
@@ -425,8 +421,19 @@ void test_data_combinations(const std::vector<column>& input_data,
             }
         };
 
+        auto check_header = [&p = p, &header = header, include_header,
+                             header_line] {
+            if (include_header) {
+                if constexpr (!setup::ignore_header) {
+                    CHECK_EQ_ARRAY(header, p.header());
+                    CHECK_EQ(header_line, p.raw_header());
+                }
+            }
+        };
+
         int num_columns = layout.size();
         for (size_t i = 0; i < n + 1; ++i) {
+            check_header();
             try {
                 switch (num_columns) {
                 case 1: {