Fix the default value for create_hook_set_value()

colcon_core/shell/__init__.py

@@ -188,7 +188,11 @@ def create_hook_set_value(
  :param str pkg_name: The package name
  :param str name: The name of the environment variable
  :param str value: The value to be set. If an empty string is passed the
- environment variable should be set to the prefix path.
+ environment variable should be set to the prefix path at the time the
+ hook is sourced (from COLCON_CURRENT_PREFIX).
+ Note that the install-space may have been relocated, and the final
+ value may differ from the value of argument prefix_path, where
+ the hook was originally installed to.
  :returns: The relative path to the created hook script
  :rtype: Path
  """

colcon_core/shell/bat.py

@@ -95,7 +95,7 @@
  ('%s.bat' % env_hook_name)
  logger.info("Creating environment hook '%s'" % hook_path)
  if value == '':
- value = '%COLCON_PREFIX_PATH%'
+ value = '%COLCON_CURRENT_PREFIX%'
  expand_template(
  Path(__file__).parent / 'template' / 'hook_set_value.bat.em',
  hook_path, {'name': name, 'value': value})

colcon_core/shell/sh.py

@@ -97,7 +97,7 @@
  ('%s.sh' % env_hook_name)
  logger.info("Creating environment hook '%s'" % hook_path)
  if value == '':
- value = '$COLCON_PREFIX_PATH'
+ value = '$COLCON_CURRENT_PREFIX'
  expand_template(
  Path(__file__).parent / 'template' / 'hook_set_value.sh.em',
  hook_path, {'name': name, 'value': value})