Add expanding the ~/ to the full home dir of user in the path to the map yaml.

nav2_map_server/include/nav2_map_server/map_io.hpp

@@ -98,6 +98,17 @@ bool saveMapToFile(
   const nav_msgs::msg::OccupancyGrid & map,
   const SaveParameters & save_parameters);
 
+/**
+ * @brief Expand ~/ to home user dir.
+ * @param yaml_filename Name of input YAML file.
+ * @param home_dir Expanded `~/`home dir or empty string if HOME not set
+ *
+ * @return Expanded string or input string if `~/` not expanded
+ */
+std::string expand_user_home_dir_if_needed(
+  std::string yaml_filename,
+  std::string home_dir);
+
 }  // namespace nav2_map_server
 
 #endif  // NAV2_MAP_SERVER__MAP_IO_HPP_

nav2_map_server/src/map_io.cpp

@@ -39,6 +39,7 @@
 #include <vector>
 #include <fstream>
 #include <stdexcept>
+#include <cstdlib>
 
 #include "Magick++.h"
 #include "nav2_util/geometry_utils.hpp"
@@ -115,9 +116,33 @@ T yaml_get_value(const YAML::Node & node, const std::string & key)
   }
 }
 
+std::string get_home_dir()
+{
+  if (const char * home_dir = std::getenv("HOME")) {
+    return std::string{home_dir};
+  }
+  return std::string{};
+}
+
+std::string expand_user_home_dir_if_needed(
+  std::string yaml_filename,
+  std::string home_variable_value)
+{
+  if (yaml_filename.size() < 2 || !(yaml_filename[0] == '~' && yaml_filename[1] == '/')) {
+    return yaml_filename;
+  }
+  if (home_variable_value.empty()) {
+    std::cout << "[INFO] [map_io]: Map yaml file name starts with '~/' but no HOME variable set. \n"
+              << "[INFO] [map_io] User home dir will be not expanded \n";
+    return yaml_filename;
+  }
+  const std::string prefix{home_variable_value};
+  return yaml_filename.replace(0, 1, prefix);
+}
+
 LoadParameters loadMapYaml(const std::string & yaml_filename)
 {
-  YAML::Node doc = YAML::LoadFile(yaml_filename);
+  YAML::Node doc = YAML::LoadFile(expand_user_home_dir_if_needed(yaml_filename, get_home_dir()));
   LoadParameters load_parameters;
 
   auto image_file_name = yaml_get_value<std::string>(doc, "image");
@@ -295,7 +320,6 @@ LOAD_MAP_STATUS loadMapFromYaml(
       " for reason: " << e.what() << std::endl;
     return INVALID_MAP_METADATA;
   }
-
   try {
     loadMapFromFile(load_parameters, map);
   } catch (std::exception & e) {

nav2_map_server/test/unit/test_map_io.cpp

@@ -311,3 +311,30 @@ TEST_F(MapIOTester, loadInvalidYAML)
   LoadParameters loadParameters;
   ASSERT_ANY_THROW(loadParameters = loadMapYaml(path(TEST_DIR) / path("invalid_file.yaml")));
 }
+
+TEST(HomeUserExpanderTestSuite, homeUserExpanderShouldNotChangeInputStringWhenShorterThanTwo)
+{
+  const std::string emptyFileName{};
+  ASSERT_EQ(emptyFileName, expand_user_home_dir_if_needed(emptyFileName, "/home/user"));
+}
+
+TEST(
+  HomeUserExpanderTestSuite,
+  homeUserExpanderShouldNotChangeInputStringWhenInputStringDoesNotStartWithHomeSequence)
+{
+  const std::string fileName{"valid_file.yaml"};
+  ASSERT_EQ(fileName, expand_user_home_dir_if_needed(fileName, "/home/user"));
+}
+
+TEST(HomeUserExpanderTestSuite, homeUserExpanderShouldNotChangeInputStringWhenHomeVariableNotFound)
+{
+  const std::string fileName{"~/valid_file.yaml"};
+  ASSERT_EQ(fileName, expand_user_home_dir_if_needed(fileName, ""));
+}
+
+TEST(HomeUserExpanderTestSuite, homeUserExpanderShouldExpandHomeSequenceWhenHomeVariableSet)
+{
+  const std::string fileName{"~/valid_file.yaml"};
+  const std::string expectedOutputFileName{"/home/user/valid_file.yaml"};
+  ASSERT_EQ(expectedOutputFileName, expand_user_home_dir_if_needed(fileName, "/home/user"));
+}