Make sure features with the same clipid also have matching attributes

decode.cpp

@@ -231,10 +231,31 @@ std::vector<mvt_feature> handle(std::string message, int z, unsigned x, unsigned
 	return pending;
 }
 
+struct by_clipid {
+	bool operator()(const mvt_feature &a, const mvt_feature &b) {
+		return a.clipid < b.clipid;
+	}
+};
+
 void handle_split(std::vector<mvt_feature> todo) {
 	if (todo.size() > 0) {
 		printf("doing partial feature\n");
 	}
+
+	std::sort(todo.begin(), todo.end(), by_clipid());
+
+	for (size_t i = 1; i < todo.size(); i++) {
+		if (todo[i - 1].clipid > todo[i].clipid) {
+			fprintf(stderr, "Internal error: failed to sort by clipid\n");
+			exit(EXIT_FAILURE);
+		}
+		if (todo[i - 1].clipid == todo[i].clipid) {
+			if (todo[i - 1].intern_tags != todo[i].intern_tags) {
+				fprintf(stderr, "Feature clipids match but attributes don't\n");
+				exit(EXIT_FAILURE);
+			}
+		}
+	}
 }
 
 void decode(char *fname, int z, unsigned x, unsigned y, std::set<std::string> const &to_decode, bool pipeline, bool stats) {

mvt.cpp

@@ -447,6 +447,24 @@ bool mvt_value::operator<(const mvt_value &o) const {
 	return false;
 }
 
+bool mvt_value::operator==(const mvt_value &o) const {
+	if (type != o.type) {
+		return false;
+	}
+
+	if ((type == mvt_string && string_value == o.string_value) ||
+	    (type == mvt_float && numeric_value.float_value == o.numeric_value.float_value) ||
+	    (type == mvt_double && numeric_value.double_value == o.numeric_value.double_value) ||
+	    (type == mvt_int && numeric_value.int_value == o.numeric_value.int_value) ||
+	    (type == mvt_uint && numeric_value.uint_value == o.numeric_value.uint_value) ||
+	    (type == mvt_sint && numeric_value.sint_value == o.numeric_value.sint_value) ||
+	    (type == mvt_bool && numeric_value.bool_value == o.numeric_value.bool_value)) {
+		return true;
+	}
+
+	return false;
+}
+
 static std::string quote(std::string const &s) {
 	std::string buf;
 

mvt.hpp

@@ -95,6 +95,8 @@ struct mvt_value {
 		this->string_value = "";
 		this->numeric_value.double_value = 0;
 	}
+
+	bool operator==(const mvt_value &o) const;
 };
 
 struct mvt_layer {

write_json.cpp

@@ -227,18 +227,18 @@ void json_writer::adds(std::string const &str) {
 }
 
 static void aprintf(std::string *buf, const char *format, ...) {
-        va_list ap;
-        char *tmp;
+	va_list ap;
+	char *tmp;
 
-        va_start(ap, format);
-        if (vasprintf(&tmp, format, ap) < 0) {
-                fprintf(stderr, "memory allocation failure\n");
-                exit(EXIT_FAILURE);
-        }
-        va_end(ap);
+	va_start(ap, format);
+	if (vasprintf(&tmp, format, ap) < 0) {
+		fprintf(stderr, "memory allocation failure\n");
+		exit(EXIT_FAILURE);
+	}
+	va_end(ap);
 
-        buf->append(tmp, strlen(tmp));
-        free(tmp);
+	buf->append(tmp, strlen(tmp));
+	free(tmp);
 }
 
 struct lonlat {