Improve primary shell heuristics

colcon_powershell/shell/powershell.py

@@ -15,6 +15,7 @@
 from colcon_core.shell import logger
 from colcon_core.shell import ShellExtensionPoint
 from colcon_core.shell.template import expand_template
+import psutil
 
 """Environment variable to override the CMake executable"""
 POWERSHELL_COMMAND_ENVIRONMENT_VARIABLE = EnvironmentVariable(
@@ -44,6 +45,20 @@ def which_executable(environment_variable, executable_name):
     POWERSHELL_COMMAND_ENVIRONMENT_VARIABLE.name, powershell_executable_name)
 
 
+def parent_process_is_powershell():
+    """Determine if the parent process is PowerShell.
+
+    In case the executable name is not found,
+    it is assumed that the parent process is not PowerShell.
+    """
+    parent = psutil.Process().parent()
+    if parent is None:
+        return False
+
+    parent_name = parent.name()
+    return parent_name == powershell_executable_name
+
+
 class PowerShellExtension(ShellExtensionPoint):
     """Generate `.ps1` scripts to extend the environment."""
 
@@ -66,7 +81,7 @@ def __init__(self):  # noqa: D107
             pathexts = os.environ.get('PATHEXT', '').lower().split(os.pathsep)
             self._is_primary = '.cpl' in pathexts
         else:
-            self._is_primary = bool(os.environ.get('PSModulePath'))
+            self._is_primary = parent_process_is_powershell()
 
         if not POWERSHELL_EXECUTABLE:
             self._is_primary = False

setup.cfg

@@ -27,6 +27,7 @@ keywords = colcon
 python_requires = >=3.6
 install_requires =
   colcon-core>=0.12.0
+  psutil>=5.4.3
 packages = find:
 zip_safe = false
 

stdeb.cfg

@@ -1,6 +1,6 @@
 [colcon-powershell]
 No-Python2:
-Depends3: python3-colcon-core (>= 0.12.0)
+Depends3: python3-colcon-core (>= 0.12.0), python3-psutil (>= 5.4.3)
 Suite: focal jammy noble resolute bookworm trixie
 X-Python3-Version: >= 3.6
 Upstream-Version-Suffix: +upstream

test/spell_check.words

@@ -9,6 +9,7 @@ pathlib
 plugin
 powershell
 prepend
+psutil
 pwsh
 pydocstyle
 pytest