Give warning when no headers specified in headers section

src/HeadersParser.h

@@ -83,14 +83,29 @@ namespace snowcrash {
 
                 mdp::ByteBuffer subject = node->children().front().text;
                 TrimString(subject);
-                
+
                 if (RegexMatch(subject, HeadersRegex))
                     return HeadersSectionType;
             }
 
             return UndefinedSectionType;
         }
 
+        static void finalize(const MarkdownNodeIterator& node,
+                             SectionParserData& pd,
+                             Report& report,
+                             Headers& out) {
+
+            if (out.empty()) {
+
+                // WARN: No headers defined
+                mdp::CharactersRangeSet sourceMap = mdp::BytesRangeSetToCharactersRangeSet(node->sourceMap, pd.sourceData);
+                report.warnings.push_back(Warning("No headers defined in headers section",
+                                                  EmptyDefinitionWarning,
+                                                  sourceMap));
+            }
+        }
+
         /** Retrieve headers from content */
         static void headersFromContent(const MarkdownNodeIterator& node,
                                        const mdp::ByteBuffer& content,

test/test-HeadersParser.cc

@@ -84,7 +84,7 @@ TEST_CASE("parse malformed headers fixture", "[headers]")
     REQUIRE(headers[1].second == "Hello World!");
 }
 
-TEST_CASE("hparser/parse-multiple-blocks", "Parse header section composed of multiple blocks")
+TEST_CASE("Parse header section composed of multiple blocks", "[headers]")
 {
     // Blueprint in question:
     //R"(
@@ -116,3 +116,17 @@ TEST_CASE("hparser/parse-multiple-blocks", "Parse header section composed of mul
     REQUIRE(headers[2].first == "X-My-Header");
     REQUIRE(headers[2].second == "42");
 }
+
+TEST_CASE("Parse header section with missing headers", "[headers]")
+{
+    mdp::ByteBuffer source = "+ Headers\n\n";
+
+    Headers headers;
+    Report report;
+    SectionParserHelper<Headers, HeadersParser>::parse(source, HeadersSectionType, report, headers);
+
+    REQUIRE(report.error.code == Error::OK);
+    REQUIRE(report.warnings.size() == 1); // no headers
+
+    REQUIRE(headers.size() == 0);
+}