Bash completion for flags

CMakeLists.txt

@@ -70,6 +70,9 @@ set(IGN_MSGS_VER ${ignition-msgs5_VERSION_MAJOR})
 #--------------------------------------
 # Find if ign command is available
 find_program(HAVE_IGN_TOOLS ign)
+if (HAVE_IGN_TOOLS)
+  set(IGN_TOOLS_VER 1)
+endif()
 
 #--------------------------------------
 # Find QT

src/CMakeLists.txt

@@ -46,7 +46,14 @@ ign_build_tests(TYPE UNIT
                 LIB_DEPS
                   ${IGNITION-MATH_LIBRARIES}
                   TINYXML2::TINYXML2
+                TEST_LIST
+                  gtest_targets
 )
 
+foreach(test ${gtest_targets})
+  target_compile_definitions(${test} PRIVATE
+    "PROJECT_SOURCE_DIR=\"${PROJECT_SOURCE_DIR}\"")
+endforeach()
+
 add_subdirectory(cmd)
 add_subdirectory(plugins)

src/cmd/CMakeLists.txt

@@ -1,4 +1,4 @@
-# Generate a the ruby script.
+# Generate the ruby script.
 # Note that the major version of the library is included in the name.
 if (APPLE)
   set(IGN_LIBRARY_NAME lib${PROJECT_NAME_LOWER}.dylib)
@@ -11,3 +11,15 @@ configure_file(
 
 # Install the ruby command line library in an unversioned location.
 install(FILES ${CMAKE_CURRENT_BINARY_DIR}/cmdgui${PROJECT_VERSION_MAJOR}.rb DESTINATION lib/ruby/ignition)
+
+# Tack version onto and install the bash completion script
+configure_file(
+  "gui.bash_completion.sh"
+    "${CMAKE_CURRENT_BINARY_DIR}/gui${PROJECT_VERSION_MAJOR}.bash_completion.sh" @ONLY)
+if (HAVE_IGN_TOOLS)
+  install(
+    FILES
+      ${CMAKE_CURRENT_BINARY_DIR}/gui${PROJECT_VERSION_MAJOR}.bash_completion.sh
+    DESTINATION
+      ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_DATAROOTDIR}/gz/gz${IGN_TOOLS_VER}.completion.d)
+endif()

src/cmd/gui.bash_completion.sh

@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+#
+# Copyright (C) 2022 Open Source Robotics Foundation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# bash tab-completion
+
+# This is a per-library function definition, used in conjunction with the
+# top-level entry point in ign-tools.
+
+GZ_GUI_COMPLETION_LIST="
+  -l --list
+  -s --standalone
+  -c --config
+  -v --verbose
+  -h --help
+  --force-version
+  --versions
+"
+
+function _gz_gui
+{
+  if [[ ${COMP_WORDS[COMP_CWORD]} == -* ]]; then
+    # Specify options (-*) word list for this subcommand
+    COMPREPLY=($(compgen -W "$GZ_GUI_COMPLETION_LIST" \
+      -- "${COMP_WORDS[COMP_CWORD]}" ))
+    return
+  else
+    # Just use bash default auto-complete, because we never have two
+    # subcommands in the same line. If that is ever needed, change here to
+    # detect subsequent subcommands
+    COMPREPLY=($(compgen -o default -- "${COMP_WORDS[COMP_CWORD]}"))
+    return
+  fi
+}
+
+function _gz_gui_flags
+{
+  for word in $GZ_GUI_COMPLETION_LIST; do
+    echo "$word"
+  done
+}

src/ign_TEST.cc

@@ -19,6 +19,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+#include <fstream>
 #include <string>
 
 #include <ignition/common/Filesystem.hh>
@@ -96,3 +97,33 @@ TEST_F(CmdLine, IGN_UTILS_TEST_ENABLED_ONLY_ON_LINUX(list))
   EXPECT_TRUE(common::exists(common::joinPaths(this->kFakeHome, ".ignition",
       "gui")));
 }
+
+//////////////////////////////////////////////////
+/// \brief Check --help message and bash completion script for consistent flags
+TEST(ignTest, GuiHelpVsCompletionFlags)
+{
+  // Flags in help message
+  std::string helpOutput = custom_exec_str("ign gui --help");
+
+  // Call the output function in the bash completion script
+  std::string scriptPath = common::joinPaths(std::string(PROJECT_SOURCE_DIR),
+    "src", "cmd", "gui.bash_completion.sh");
+
+  // Equivalent to:
+  // sh -c "bash -c \". /path/to/gui.bash_completion.sh; _gz_gui_flags\""
+  std::string cmd = "bash -c \". " + scriptPath + "; _gz_gui_flags\"";
+  std::string scriptOutput = custom_exec_str(cmd);
+
+  // Tokenize script output
+  std::istringstream iss(scriptOutput);
+  std::vector<std::string> flags((std::istream_iterator<std::string>(iss)),
+    std::istream_iterator<std::string>());
+
+  EXPECT_GT(flags.size(), 0u);
+
+  // Match each flag in script output with help message
+  for (std::string flag : flags)
+  {
+    EXPECT_NE(std::string::npos, helpOutput.find(flag)) << helpOutput;
+  }
+}