From d71de779156dc3704e6daad079456be32b97b696 Mon Sep 17 00:00:00 2001
From: sleeptightAnsiC <91839286+sleeptightAnsiC@users.noreply.github.com>
Date: Fri, 22 Mar 2024 15:45:55 +0100
Subject: [PATCH 1/8] fix: handling I/O failures + refactor: unify logging and
 assertions

This commit also...
...reverts: https://github.com/adamrehn/ue4cli/commit/fed71c1af4cffe3fed9358b08430068ad9454b77
...fixes: https://github.com/adamrehn/ue4cli/issues/29
---
 ue4cli/JsonDataManager.py      |  5 +----
 ue4cli/UnrealManagerBase.py    | 16 +++++++++-------
 ue4cli/UnrealManagerWindows.py |  2 +-
 ue4cli/Utility.py              |  8 ++++----
 ue4cli/cli.py                  | 25 +++++++++++++++++++++----
 5 files changed, 36 insertions(+), 20 deletions(-)

diff --git a/ue4cli/JsonDataManager.py b/ue4cli/JsonDataManager.py
index 53fbb77..a520143 100644
--- a/ue4cli/JsonDataManager.py
+++ b/ue4cli/JsonDataManager.py
@@ -28,10 +28,7 @@ def getDictionary(self):
 		Retrieves the entire data dictionary
 		"""
 		if os.path.exists(self.jsonFile):
-			try:
-				return json.loads(Utility.readFile(self.jsonFile))
-			except json.JSONDecodeError as err:
-				raise UnrealManagerException('malformed JSON configuration file "{}" ({})'.format(self.jsonFile, err))
+			return json.loads(Utility.readFile(self.jsonFile))
 		else:
 			return {}
 	
diff --git a/ue4cli/UnrealManagerBase.py b/ue4cli/UnrealManagerBase.py
index 763557f..2952c47 100644
--- a/ue4cli/UnrealManagerBase.py
+++ b/ue4cli/UnrealManagerBase.py
@@ -44,13 +44,13 @@ def setEngineRootOverride(self, rootDir):
 		# Set the new root directory
 		rootDir = os.path.abspath(rootDir)
 		ConfigurationManager.setConfigKey('rootDirOverride', rootDir)
-		print('Set engine root path override: {}'.format(rootDir))
+		Utility.printStderr('Setting engine root path override:', str(rootDir))
 		
 		# Check that the specified directory is valid and warn the user if it is not
 		try:
 			self.getEngineVersion()
 		except:
-			print('Warning: the specified directory does not appear to contain a valid version of the Unreal Engine.')
+			UnrealManagerException('the specified directory does not appear to contain a valid version of the Unreal Engine.')
 	
 	def clearEngineRootOverride(self):
 		"""
@@ -94,7 +94,7 @@ def getEngineVersion(self, outputFormat = 'full'):
 		
 		# Verify that the requested output format is valid
 		if outputFormat not in formats:
-			raise Exception('unreconised version output format "{}"'.format(outputFormat))
+			raise UnrealManagerException('unreconised version output format "{}"'.format(outputFormat))
 		
 		return formats[outputFormat]
 	
@@ -538,7 +538,7 @@ def listAutomationTests(self, projectFile):
 		# Detect if the Editor terminated abnormally (i.e. not triggered by `automation quit`)
 		# In Unreal Engine 4.27.0, the exit method changed from RequestExit to RequestExitWithStatus
 		if 'PlatformMisc::RequestExit(' not in logOutput.stdout and 'PlatformMisc::RequestExitWithStatus(' not in logOutput.stdout:
-			raise RuntimeError(
+			raise UnrealManagerException(
 				'failed to retrieve the list of automation tests!' +
 				' stdout was: "{}", stderr was: "{}"'.format(logOutput.stdout, logOutput.stderr)
 			)
@@ -556,7 +556,7 @@ def automationTests(self, dir=os.getcwd(), args=[]):
 		
 		# Verify that at least one argument was supplied
 		if len(args) == 0:
-			raise RuntimeError('at least one test name must be specified')
+			raise UnrealManagerException('at least one test name must be specified')
 		
 		# Gather any additional arguments to pass directly to the Editor
 		extraArgs = []
@@ -605,7 +605,7 @@ def automationTests(self, dir=os.getcwd(), args=[]):
 			# Detect abnormal exit conditions (those not triggered by `automation quit`)
 			# In Unreal Engine 4.27.0, the exit method changed from RequestExit to RequestExitWithStatus
 			if 'PlatformMisc::RequestExit(' not in logOutput.stdout and 'PlatformMisc::RequestExitWithStatus(' not in logOutput.stdout:
-				sys.exit(1)
+				raise UnrealManagerException('abnormal exit condition')
 			
 			# Since UE4 doesn't consistently produce accurate exit codes across all platforms, we need to rely on
 			# text-based heuristics to detect failed automation tests or errors related to not finding any tests to run
@@ -618,12 +618,14 @@ def automationTests(self, dir=os.getcwd(), args=[]):
 			]
 			for errorStr in errorStrings:
 				if errorStr in logOutput.stdout:
-					sys.exit(1)
+					raise UnrealManagerException('abnormal exit condition')
 			
 			# If an explicit exit code was specified in the output text then identify it and propagate it
 			match = re.search('TEST COMPLETE\\. EXIT CODE: ([0-9]+)', logOutput.stdout + logOutput.stderr)
 			if match is not None:
 				sys.exit(int(match.group(1)))
+			else:
+				raise UnrealManagerException('abnormal exit condition')
 	
 	# "Protected" methods
 	
diff --git a/ue4cli/UnrealManagerWindows.py b/ue4cli/UnrealManagerWindows.py
index 535c69b..c229fbf 100644
--- a/ue4cli/UnrealManagerWindows.py
+++ b/ue4cli/UnrealManagerWindows.py
@@ -52,7 +52,7 @@ def generateProjectFiles(self, dir=os.getcwd(), args=[]):
 		# If we are using our custom batch file, use the appropriate arguments
 		genScript = self.getGenerateScript()
 		projectFile = self.getProjectDescriptor(dir)
-		print(projectFile)
+		Utility.printStderr('Using project file:', projectFile)
 		if '.ue4\\GenerateProjectFiles.bat' in genScript:
 			Utility.run([genScript, projectFile], raiseOnError=True)
 		else:
diff --git a/ue4cli/Utility.py b/ue4cli/Utility.py
index 65e4e12..ae9aab2 100644
--- a/ue4cli/Utility.py
+++ b/ue4cli/Utility.py
@@ -21,7 +21,7 @@ def printStderr(*args, **kwargs):
 		Prints to stderr instead of stdout
 		"""
 		if os.environ.get('UE4CLI_QUIET', '0') != '1':
-			print(*args, file=sys.stderr, **kwargs)
+			print('(ue4cli)', *args, end='\n', file=sys.stderr, **kwargs)
 	
 	@staticmethod
 	def readFile(filename):
@@ -123,7 +123,7 @@ def capture(command, input=None, cwd=None, shell=False, raiseOnError=False):
 		
 		# If the child process failed and we were asked to raise an exception, do so
 		if raiseOnError == True and proc.returncode != 0:
-			raise Exception(
+			raise subprocess.SubprocessError(
 				'child process ' + str(command) +
 				' failed with exit code ' + str(proc.returncode) +
 				'\nstdout: "' + stdout + '"' +
@@ -143,7 +143,7 @@ def run(command, cwd=None, shell=False, raiseOnError=False):
 		
 		returncode = subprocess.call(command, cwd=cwd, shell=shell)
 		if raiseOnError == True and returncode != 0:
-			raise Exception('child process ' + str(command) + ' failed with exit code ' + str(returncode))
+			raise subprocess.SubprocessError('child process ' + str(command) + ' failed with exit code ' + str(returncode))
 		return returncode
 	
 	@staticmethod
@@ -152,4 +152,4 @@ def _printCommand(command):
 		Prints a command if verbose output is enabled
 		"""
 		if os.environ.get('UE4CLI_VERBOSE', '0') == '1':
-			Utility.printStderr('[UE4CLI] EXECUTE COMMAND:', command)
+			Utility.printStderr('EXECUTE COMMAND:', command)
diff --git a/ue4cli/cli.py b/ue4cli/cli.py
index d5f51e3..d08d327 100644
--- a/ue4cli/cli.py
+++ b/ue4cli/cli.py
@@ -2,7 +2,10 @@
 from .PluginManager import PluginManager
 from .UnrealManagerException import UnrealManagerException
 from .UnrealManagerFactory import UnrealManagerFactory
-import os, sys
+from .Utility import Utility
+from subprocess import SubprocessError
+from json import JSONDecodeError
+import os, sys, logging
 
 # Our list of supported commands
 SUPPORTED_COMMANDS = {
@@ -201,6 +204,7 @@ def displayHelp():
 
 def main():
 	try:
+		logger = logging.getLogger(__name__)
 		
 		# Perform plugin detection and register our detected plugins
 		plugins = PluginManager.getPlugins()
@@ -222,7 +226,20 @@ def main():
 			SUPPORTED_COMMANDS[command]['action'](manager, args)
 		else:
 			raise UnrealManagerException('unrecognised command "' + command + '"')
-		
-	except UnrealManagerException as e:
-		print('Error: ' + str(e))
+	except (
+			UnrealManagerException,
+			OSError,
+			SubprocessError,
+			JSONDecodeError,
+			KeyboardInterrupt,
+			) as e:
+		Utility.printStderr('(' + type(e).__name__ + ')', str(e))
+		sys.exit(1)
+	except BaseException as e:
+		Utility.printStderr('Unhandled exception! Crashing...')
+		logging.basicConfig(level=logging.DEBUG)
+		logger.exception(e)
+		Utility.printStderr('ue4cli has crashed! Please, report it at: https://github.com/adamrehn/ue4cli/issues')
 		sys.exit(1)
+
+

From c17c247a4f09e9281db24c11e1239ab32b8c012f Mon Sep 17 00:00:00 2001
From: sleeptightAnsiC <91839286+sleeptightAnsiC@users.noreply.github.com>
Date: Sat, 23 Mar 2024 00:21:53 +0100
Subject: [PATCH 2/8] fix: add missing 'raise' keyword

---
 ue4cli/UnrealManagerBase.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ue4cli/UnrealManagerBase.py b/ue4cli/UnrealManagerBase.py
index 2952c47..da42208 100644
--- a/ue4cli/UnrealManagerBase.py
+++ b/ue4cli/UnrealManagerBase.py
@@ -50,7 +50,7 @@ def setEngineRootOverride(self, rootDir):
 		try:
 			self.getEngineVersion()
 		except:
-			UnrealManagerException('the specified directory does not appear to contain a valid version of the Unreal Engine.')
+			raise UnrealManagerException('the specified directory does not appear to contain a valid version of the Unreal Engine.')
 	
 	def clearEngineRootOverride(self):
 		"""

From d1d5ac5bc3ac1fd51c643a539a2bce624378bbc6 Mon Sep 17 00:00:00 2001
From: sleeptightAnsiC <91839286+sleeptightAnsiC@users.noreply.github.com>
Date: Sat, 23 Mar 2024 00:49:01 +0100
Subject: [PATCH 3/8] reverse 'else' block - Adding it here was unsave - it
 could produce unwanted behavior

---
 ue4cli/UnrealManagerBase.py | 2 --
 1 file changed, 2 deletions(-)

diff --git a/ue4cli/UnrealManagerBase.py b/ue4cli/UnrealManagerBase.py
index da42208..33887a5 100644
--- a/ue4cli/UnrealManagerBase.py
+++ b/ue4cli/UnrealManagerBase.py
@@ -624,8 +624,6 @@ def automationTests(self, dir=os.getcwd(), args=[]):
 			match = re.search('TEST COMPLETE\\. EXIT CODE: ([0-9]+)', logOutput.stdout + logOutput.stderr)
 			if match is not None:
 				sys.exit(int(match.group(1)))
-			else:
-				raise UnrealManagerException('abnormal exit condition')
 	
 	# "Protected" methods
 	

From 0e62c1214598bf54abf606549a0c8196be316129 Mon Sep 17 00:00:00 2001
From: sleeptightAnsiC <91839286+sleeptightAnsiC@users.noreply.github.com>
Date: Sat, 23 Mar 2024 13:58:51 +0100
Subject: [PATCH 4/8] catch SystemExit as we are using it when performing
 automation tests

---
 ue4cli/cli.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/ue4cli/cli.py b/ue4cli/cli.py
index d08d327..73f7a9d 100644
--- a/ue4cli/cli.py
+++ b/ue4cli/cli.py
@@ -232,6 +232,7 @@ def main():
 			SubprocessError,
 			JSONDecodeError,
 			KeyboardInterrupt,
+			SystemExit,
 			) as e:
 		Utility.printStderr('(' + type(e).__name__ + ')', str(e))
 		sys.exit(1)

From 2747bf640c445f645f8854b369fc78a4a84a5924 Mon Sep 17 00:00:00 2001
From: sleeptightAnsiC <91839286+sleeptightAnsiC@users.noreply.github.com>
Date: Sat, 23 Mar 2024 21:18:54 +0100
Subject: [PATCH 5/8] refactor: wrap every I/O call with try-except block and
 pass the error to UtilityException with meaningful message

---
 ue4cli/JsonDataManager.py      | 11 +++++++++--
 ue4cli/UE4BuildInterrogator.py | 18 +++++++++++++++---
 ue4cli/UnrealManagerBase.py    | 28 ++++++++++++++++++----------
 ue4cli/Utility.py              | 31 +++++++++++++++++++------------
 ue4cli/UtilityException.py     |  2 ++
 ue4cli/cli.py                  |  9 ++-------
 6 files changed, 65 insertions(+), 34 deletions(-)
 create mode 100644 ue4cli/UtilityException.py

diff --git a/ue4cli/JsonDataManager.py b/ue4cli/JsonDataManager.py
index a520143..ba6f90d 100644
--- a/ue4cli/JsonDataManager.py
+++ b/ue4cli/JsonDataManager.py
@@ -1,5 +1,6 @@
 from .UnrealManagerException import UnrealManagerException
 from .Utility import Utility
+from .UtilityException import UtilityException
 import json, os, platform
 
 class JsonDataManager(object):
@@ -28,7 +29,10 @@ def getDictionary(self):
 		Retrieves the entire data dictionary
 		"""
 		if os.path.exists(self.jsonFile):
-			return json.loads(Utility.readFile(self.jsonFile))
+			try:
+				return json.loads(Utility.readFile(self.jsonFile))
+			except json.JSONDecodeError as e:
+				raise UtilityException(f'failed to load {str(self.jsonFile)} due to {type(e).__name__} {str(e)}')
 		else:
 			return {}
 	
@@ -48,7 +52,10 @@ def setDictionary(self, data):
 		# Create the directory containing the JSON file if it doesn't already exist
 		jsonDir = os.path.dirname(self.jsonFile)
 		if os.path.exists(jsonDir) == False:
-			os.makedirs(jsonDir)
+			try:
+				os.makedirs(jsonDir)
+			except OSError as e:
+				raise UtilityException(f'failed to create directory {str(jsonDir)} due to {type(e).__name__} {str(e)}')
 		
 		# Store the dictionary
 		Utility.writeFile(self.jsonFile, json.dumps(data))
diff --git a/ue4cli/UE4BuildInterrogator.py b/ue4cli/UE4BuildInterrogator.py
index 12a42d8..0575f57 100644
--- a/ue4cli/UE4BuildInterrogator.py
+++ b/ue4cli/UE4BuildInterrogator.py
@@ -2,11 +2,14 @@
 from .UnrealManagerException import UnrealManagerException
 from .CachedDataManager import CachedDataManager
 from .Utility import Utility
+from .UtilityException import UtilityException
 import json, os, platform, shutil, tempfile
 
 class UE4BuildInterrogator(object):
 	
 	def __init__(self, engineRoot, engineVersion, engineVersionHash, runUBTFunc):
+		# WARN: os.path.realpath can potentially fail with OSError,
+		# but if it ever happens, this is most likely bug in our code
 		self.engineRoot = os.path.realpath(engineRoot)
 		self.engineSourceDir = 'Engine/Source/'
 		self.engineVersion = engineVersion
@@ -160,7 +163,10 @@ def _getThirdPartyLibs(self, platformIdentifier, configuration):
 		sentinelBackup = sentinelFile + '.bak'
 		renameSentinel = os.path.exists(sentinelFile) and os.environ.get('UE4CLI_SENTINEL_RENAME', '0') == '1'
 		if renameSentinel == True:
-			shutil.move(sentinelFile, sentinelBackup)
+			try:
+				shutil.move(sentinelFile, sentinelBackup)
+			except OSError as e:
+				raise UtilityException(f'failed to move {str(sentinelFile)} to {str(sentinelBackup)} due to {type(e).__name__} {str(e)}')
 		
 		# Invoke UnrealBuildTool in JSON export mode (make sure we specify gathering mode, since this is a prerequisite of JSON export)
 		# (Ensure we always perform sentinel file cleanup even when errors occur)
@@ -172,10 +178,16 @@ def _getThirdPartyLibs(self, platformIdentifier, configuration):
 				self.runUBTFunc('UE4Editor', platformIdentifier, configuration, args)
 		finally:
 			if renameSentinel == True:
-				shutil.move(sentinelBackup, sentinelFile)
+				try:
+					shutil.move(sentinelBackup, sentinelFile)
+				except OSError as e:
+					raise UtilityException(f'failed to move {str(sentinelBackup)} to {str(sentinelFile)} due to {type(e).__name__} {str(e)}')
 		
 		# Parse the JSON output
-		result = json.loads(Utility.readFile(jsonFile))
+		try:
+			result = json.loads(Utility.readFile(jsonFile))
+		except json.JSONDecodeError as e:
+			raise UtilityException(f'failed to load {str(jsonFile)} due to {type(e).__name__} {str(e)}')
 		
 		# Extract the list of third-party library modules
 		# (Note that since UE4.21, modules no longer have a "Type" field, so we must
diff --git a/ue4cli/UnrealManagerBase.py b/ue4cli/UnrealManagerBase.py
index 33887a5..3efc24c 100644
--- a/ue4cli/UnrealManagerBase.py
+++ b/ue4cli/UnrealManagerBase.py
@@ -5,6 +5,7 @@
 from .CachedDataManager import CachedDataManager
 from .CMakeCustomFlags import CMakeCustomFlags
 from .Utility import Utility
+from .UtilityException import UtilityException
 import glob, hashlib, json, os, re, shutil, sys
 
 class UnrealManagerBase(object):
@@ -316,8 +317,7 @@ def generateProjectFiles(self, dir=os.getcwd(), args=[]):
 		
 		# If the project is a pure Blueprint project, then we cannot generate project files
 		if os.path.exists(os.path.join(dir, 'Source')) == False:
-			Utility.printStderr('Pure Blueprint project, nothing to generate project files for.')
-			return
+			raise UnrealManagerException('Pure Blueprint project, nothing to generate project files for.')
 		
 		# Generate the project files
 		genScript = self.getGenerateScript()
@@ -354,8 +354,7 @@ def buildDescriptor(self, dir=os.getcwd(), configuration='Development', target='
 		
 		# If the project or plugin is Blueprint-only, there is no C++ code to build
 		if os.path.exists(os.path.join(dir, 'Source')) == False:
-			Utility.printStderr('Pure Blueprint {}, nothing to build.'.format(descriptorType))
-			return
+			raise UnrealManagerException('Pure Blueprint {}, nothing to build.'.format(descriptorType))
 		
 		# Verify that the specified build configuration is valid
 		if configuration not in self.validBuildConfigurations():
@@ -567,7 +566,12 @@ def automationTests(self, dir=os.getcwd(), args=[]):
 		
 		# Build the project if it isn't already built
 		Utility.printStderr('Ensuring project is built...')
-		self.buildDescriptor(dir, suppressOutput=True)
+		try:
+			self.buildDescriptor(dir, suppressOutput=True)
+		except UnrealManagerException:
+			# FIXME: Ideally, we should NOT catch every UnrealManagerException here
+			# This is currently a limitation of our API that uses only one Exception class for multiple different cases
+			pass
 		
 		# Determine which arguments we are passing to the automation test commandlet
 		projectFile = self.getProjectDescriptor(dir)
@@ -605,7 +609,7 @@ def automationTests(self, dir=os.getcwd(), args=[]):
 			# Detect abnormal exit conditions (those not triggered by `automation quit`)
 			# In Unreal Engine 4.27.0, the exit method changed from RequestExit to RequestExitWithStatus
 			if 'PlatformMisc::RequestExit(' not in logOutput.stdout and 'PlatformMisc::RequestExitWithStatus(' not in logOutput.stdout:
-				raise UnrealManagerException('abnormal exit condition')
+				raise UnrealManagerException('abnormal exit condition detected')
 			
 			# Since UE4 doesn't consistently produce accurate exit codes across all platforms, we need to rely on
 			# text-based heuristics to detect failed automation tests or errors related to not finding any tests to run
@@ -618,12 +622,12 @@ def automationTests(self, dir=os.getcwd(), args=[]):
 			]
 			for errorStr in errorStrings:
 				if errorStr in logOutput.stdout:
-					raise UnrealManagerException('abnormal exit condition')
+					raise UnrealManagerException('abnormal exit condition detected')
 			
 			# If an explicit exit code was specified in the output text then identify it and propagate it
-			match = re.search('TEST COMPLETE\\. EXIT CODE: ([0-9]+)', logOutput.stdout + logOutput.stderr)
+			match = re.search('TEST COMPLETE\\. EXIT CODE: ([1-9]+)', logOutput.stdout + logOutput.stderr)
 			if match is not None:
-				sys.exit(int(match.group(1)))
+				raise UnrealManagerException('abnormal exit condition detected')
 	
 	# "Protected" methods
 	
@@ -638,7 +642,11 @@ def _getEngineVersionDetails(self):
 		Parses the JSON version details for the latest installed version of UE4
 		"""
 		versionFile = os.path.join(self.getEngineRoot(), 'Engine', 'Build', 'Build.version')
-		return json.loads(Utility.readFile(versionFile))
+		jsonFile = Utility.readFile(versionFile)
+		try:
+			return json.loads(jsonFile)
+		except json.JSONDecodeError as e:
+			raise UtilityException(f'failed to load {str(jsonFile)} due to {type(e).__name__} {str(e)}')
 	
 	def _getEngineVersionHash(self):
 		"""
diff --git a/ue4cli/Utility.py b/ue4cli/Utility.py
index ae9aab2..17f1703 100644
--- a/ue4cli/Utility.py
+++ b/ue4cli/Utility.py
@@ -1,3 +1,4 @@
+from .UtilityException import UtilityException
 import os, platform, shlex, subprocess, sys
 
 class CommandOutput(object):
@@ -21,23 +22,29 @@ def printStderr(*args, **kwargs):
 		Prints to stderr instead of stdout
 		"""
 		if os.environ.get('UE4CLI_QUIET', '0') != '1':
-			print('(ue4cli)', *args, end='\n', file=sys.stderr, **kwargs)
+			print('(ue4cli)', *args, file=sys.stderr, **kwargs)
 	
 	@staticmethod
 	def readFile(filename):
 		"""
 		Reads data from a file
 		"""
-		with open(filename, 'rb') as f:
-			return f.read().decode('utf-8')
+		try:
+			with open(filename, 'rb') as f:
+				return f.read().decode('utf-8')
+		except OSError as e:
+			raise UtilityException(f'failed to read file {str(filename)} due to {type(e).__name__} {str(e)}')
 	
 	@staticmethod
 	def writeFile(filename, data):
 		"""
 		Writes data to a file
 		"""
-		with open(filename, 'wb') as f:
-			f.write(data.encode('utf-8'))
+		try:
+			with open(filename, 'wb') as f:
+				f.write(data.encode('utf-8'))
+		except OSError as e:
+			raise UtilityException(f'failed to write file {str(filename)} due to {type(e).__name__} {str(e)}')
 	
 	@staticmethod
 	def patchFile(filename, replacements):
@@ -123,12 +130,12 @@ def capture(command, input=None, cwd=None, shell=False, raiseOnError=False):
 		
 		# If the child process failed and we were asked to raise an exception, do so
 		if raiseOnError == True and proc.returncode != 0:
-			raise subprocess.SubprocessError(
-				'child process ' + str(command) +
-				' failed with exit code ' + str(proc.returncode) +
-				'\nstdout: "' + stdout + '"' +
-				'\nstderr: "' + stderr + '"'
-			)
+			Utility.printStderr("Warning: child process failure encountered!")
+			Utility.printStderr("printing stdout..")
+			print(stdout)
+			Utility.printStderr("printing stderr..")
+			print(stderr)
+			raise UtilityException(f'child process {str(command)} failed with exit code {str(proc.returncode)}')
 		
 		return CommandOutput(proc.returncode, stdout, stderr)
 	
@@ -143,7 +150,7 @@ def run(command, cwd=None, shell=False, raiseOnError=False):
 		
 		returncode = subprocess.call(command, cwd=cwd, shell=shell)
 		if raiseOnError == True and returncode != 0:
-			raise subprocess.SubprocessError('child process ' + str(command) + ' failed with exit code ' + str(returncode))
+			raise UtilityException(f'child process {str(command)} failed with exit code {str(returncode)}')
 		return returncode
 	
 	@staticmethod
diff --git a/ue4cli/UtilityException.py b/ue4cli/UtilityException.py
new file mode 100644
index 0000000..53af630
--- /dev/null
+++ b/ue4cli/UtilityException.py
@@ -0,0 +1,2 @@
+class UtilityException(Exception):
+	pass
diff --git a/ue4cli/cli.py b/ue4cli/cli.py
index 73f7a9d..25261fa 100644
--- a/ue4cli/cli.py
+++ b/ue4cli/cli.py
@@ -3,8 +3,7 @@
 from .UnrealManagerException import UnrealManagerException
 from .UnrealManagerFactory import UnrealManagerFactory
 from .Utility import Utility
-from subprocess import SubprocessError
-from json import JSONDecodeError
+from .UtilityException import UtilityException
 import os, sys, logging
 
 # Our list of supported commands
@@ -228,11 +227,8 @@ def main():
 			raise UnrealManagerException('unrecognised command "' + command + '"')
 	except (
 			UnrealManagerException,
-			OSError,
-			SubprocessError,
-			JSONDecodeError,
+			UtilityException,
 			KeyboardInterrupt,
-			SystemExit,
 			) as e:
 		Utility.printStderr('(' + type(e).__name__ + ')', str(e))
 		sys.exit(1)
@@ -243,4 +239,3 @@ def main():
 		Utility.printStderr('ue4cli has crashed! Please, report it at: https://github.com/adamrehn/ue4cli/issues')
 		sys.exit(1)
 
-

From 6e7c3e4647cde65dce17858bed19fb8aaf4586fa Mon Sep 17 00:00:00 2001
From: sleeptightAnsiC <91839286+sleeptightAnsiC@users.noreply.github.com>
Date: Sat, 23 Mar 2024 22:47:12 +0100
Subject: [PATCH 6/8] Refactor: create abstraction for shutil.move,
 shutil.rmtree, os.makedirs inside of Utility class

---
 ue4cli/CachedDataManager.py    |  5 +++--
 ue4cli/JsonDataManager.py      | 24 +++++++++++++++---------
 ue4cli/UE4BuildInterrogator.py | 20 ++++++--------------
 ue4cli/UnrealManagerBase.py    | 13 +++++--------
 ue4cli/UnrealManagerWindows.py |  2 +-
 ue4cli/Utility.py              | 32 +++++++++++++++++++++++++++++++-
 6 files changed, 61 insertions(+), 35 deletions(-)

diff --git a/ue4cli/CachedDataManager.py b/ue4cli/CachedDataManager.py
index 9b03753..34678a7 100644
--- a/ue4cli/CachedDataManager.py
+++ b/ue4cli/CachedDataManager.py
@@ -1,6 +1,7 @@
 from .ConfigurationManager import ConfigurationManager
 from .JsonDataManager import JsonDataManager
-import os, shutil
+from .Utility import Utility
+import os
 
 class CachedDataManager(object):
 	"""
@@ -13,7 +14,7 @@ def clearCache():
 		Clears any cached data we have stored about specific engine versions
 		"""
 		if os.path.exists(CachedDataManager._cacheDir()) == True:
-			shutil.rmtree(CachedDataManager._cacheDir())
+			Utility.removeDir(CachedDataManager._cacheDir())
 	
 	@staticmethod
 	def getCachedDataKey(engineVersionHash, key):
diff --git a/ue4cli/JsonDataManager.py b/ue4cli/JsonDataManager.py
index ba6f90d..b67fa00 100644
--- a/ue4cli/JsonDataManager.py
+++ b/ue4cli/JsonDataManager.py
@@ -1,7 +1,7 @@
 from .UnrealManagerException import UnrealManagerException
 from .Utility import Utility
 from .UtilityException import UtilityException
-import json, os, platform
+import json, os
 
 class JsonDataManager(object):
 	"""
@@ -13,6 +13,18 @@ def __init__(self, jsonFile):
 		Creates a new JsonDataManager instance for the specified JSON file
 		"""
 		self.jsonFile = jsonFile
+
+	def loads(self):
+		"""
+		Wrapper for json.loads which reads owned jsonFile and loads it
+		In case of encountering JSONDecodeError, it will raise UtilityException
+		"""
+		try:
+			path = self.jsonFile
+			file = Utility.readFile(path)
+			return json.loads(file)
+		except json.JSONDecodeError as e:
+			raise UtilityException(f'failed to load {str(path)} due to {type(e).__name__} {str(e)}')
 	
 	def getKey(self, key):
 		"""
@@ -29,10 +41,7 @@ def getDictionary(self):
 		Retrieves the entire data dictionary
 		"""
 		if os.path.exists(self.jsonFile):
-			try:
-				return json.loads(Utility.readFile(self.jsonFile))
-			except json.JSONDecodeError as e:
-				raise UtilityException(f'failed to load {str(self.jsonFile)} due to {type(e).__name__} {str(e)}')
+			return self.loads()
 		else:
 			return {}
 	
@@ -52,10 +61,7 @@ def setDictionary(self, data):
 		# Create the directory containing the JSON file if it doesn't already exist
 		jsonDir = os.path.dirname(self.jsonFile)
 		if os.path.exists(jsonDir) == False:
-			try:
-				os.makedirs(jsonDir)
-			except OSError as e:
-				raise UtilityException(f'failed to create directory {str(jsonDir)} due to {type(e).__name__} {str(e)}')
+			Utility.makeDirs(jsonDir)
 		
 		# Store the dictionary
 		Utility.writeFile(self.jsonFile, json.dumps(data))
diff --git a/ue4cli/UE4BuildInterrogator.py b/ue4cli/UE4BuildInterrogator.py
index 0575f57..098f056 100644
--- a/ue4cli/UE4BuildInterrogator.py
+++ b/ue4cli/UE4BuildInterrogator.py
@@ -3,7 +3,8 @@
 from .CachedDataManager import CachedDataManager
 from .Utility import Utility
 from .UtilityException import UtilityException
-import json, os, platform, shutil, tempfile
+from .JsonDataManager import JsonDataManager
+import os, tempfile
 
 class UE4BuildInterrogator(object):
 	
@@ -163,10 +164,7 @@ def _getThirdPartyLibs(self, platformIdentifier, configuration):
 		sentinelBackup = sentinelFile + '.bak'
 		renameSentinel = os.path.exists(sentinelFile) and os.environ.get('UE4CLI_SENTINEL_RENAME', '0') == '1'
 		if renameSentinel == True:
-			try:
-				shutil.move(sentinelFile, sentinelBackup)
-			except OSError as e:
-				raise UtilityException(f'failed to move {str(sentinelFile)} to {str(sentinelBackup)} due to {type(e).__name__} {str(e)}')
+			Utility.moveFile(sentinelFile, sentinelBackup)
 		
 		# Invoke UnrealBuildTool in JSON export mode (make sure we specify gathering mode, since this is a prerequisite of JSON export)
 		# (Ensure we always perform sentinel file cleanup even when errors occur)
@@ -178,16 +176,10 @@ def _getThirdPartyLibs(self, platformIdentifier, configuration):
 				self.runUBTFunc('UE4Editor', platformIdentifier, configuration, args)
 		finally:
 			if renameSentinel == True:
-				try:
-					shutil.move(sentinelBackup, sentinelFile)
-				except OSError as e:
-					raise UtilityException(f'failed to move {str(sentinelBackup)} to {str(sentinelFile)} due to {type(e).__name__} {str(e)}')
+				Utility.moveFile(sentinelBackup, sentinelFile)
 		
 		# Parse the JSON output
-		try:
-			result = json.loads(Utility.readFile(jsonFile))
-		except json.JSONDecodeError as e:
-			raise UtilityException(f'failed to load {str(jsonFile)} due to {type(e).__name__} {str(e)}')
+		result = JsonDataManager(jsonFile).loads()
 		
 		# Extract the list of third-party library modules
 		# (Note that since UE4.21, modules no longer have a "Type" field, so we must
@@ -200,7 +192,7 @@ def _getThirdPartyLibs(self, platformIdentifier, configuration):
 		
 		# Remove the temp directory
 		try:
-			shutil.rmtree(tempDir)
+			Utility.removeDir(tempDir)
 		except:
 			pass
 		
diff --git a/ue4cli/UnrealManagerBase.py b/ue4cli/UnrealManagerBase.py
index 3efc24c..6c9d301 100644
--- a/ue4cli/UnrealManagerBase.py
+++ b/ue4cli/UnrealManagerBase.py
@@ -5,8 +5,9 @@
 from .CachedDataManager import CachedDataManager
 from .CMakeCustomFlags import CMakeCustomFlags
 from .Utility import Utility
+from .JsonDataManager import JsonDataManager
 from .UtilityException import UtilityException
-import glob, hashlib, json, os, re, shutil, sys
+import glob, hashlib, json, os, re
 
 class UnrealManagerBase(object):
 	"""
@@ -334,8 +335,8 @@ def cleanDescriptor(self, dir=os.getcwd()):
 		
 		# Because performing a clean will also delete the engine build itself when using
 		# a source build, we simply delete the `Binaries` and `Intermediate` directories
-		shutil.rmtree(os.path.join(dir, 'Binaries'), ignore_errors=True)
-		shutil.rmtree(os.path.join(dir, 'Intermediate'), ignore_errors=True)
+		Utility.removeDir(os.path.join(dir, 'Binaries'), ignore_errors=True)
+		Utility.removeDir(os.path.join(dir, 'Intermediate'), ignore_errors=True)
 		
 		# If we are cleaning a project, also clean any plugins
 		if self.isProject(descriptor):
@@ -642,11 +643,7 @@ def _getEngineVersionDetails(self):
 		Parses the JSON version details for the latest installed version of UE4
 		"""
 		versionFile = os.path.join(self.getEngineRoot(), 'Engine', 'Build', 'Build.version')
-		jsonFile = Utility.readFile(versionFile)
-		try:
-			return json.loads(jsonFile)
-		except json.JSONDecodeError as e:
-			raise UtilityException(f'failed to load {str(jsonFile)} due to {type(e).__name__} {str(e)}')
+		return JsonDataManager(versionFile).loads()
 	
 	def _getEngineVersionHash(self):
 		"""
diff --git a/ue4cli/UnrealManagerWindows.py b/ue4cli/UnrealManagerWindows.py
index c229fbf..c11210d 100644
--- a/ue4cli/UnrealManagerWindows.py
+++ b/ue4cli/UnrealManagerWindows.py
@@ -91,7 +91,7 @@ def _customBatchScriptDir(self):
 		# If the script directory doesn't already exist, attempt to create it
 		scriptDir = os.path.join(os.environ['HOMEDRIVE'] + os.environ['HOMEPATH'], '.ue4')
 		try:
-			os.makedirs(scriptDir)
+			Utility.makeDirs(scriptDir)
 		except:
 			pass
 		
diff --git a/ue4cli/Utility.py b/ue4cli/Utility.py
index 17f1703..d3a06fd 100644
--- a/ue4cli/Utility.py
+++ b/ue4cli/Utility.py
@@ -1,5 +1,5 @@
 from .UtilityException import UtilityException
-import os, platform, shlex, subprocess, sys
+import os, platform, shlex, subprocess, sys, shutil
 
 class CommandOutput(object):
 	"""
@@ -46,6 +46,16 @@ def writeFile(filename, data):
 		except OSError as e:
 			raise UtilityException(f'failed to write file {str(filename)} due to {type(e).__name__} {str(e)}')
 	
+	@staticmethod
+	def moveFile(src, dst):
+		"""
+		Moves file from 'src' to 'dst'
+		"""
+		try:
+			shutil.move(src, dst)
+		except OSError as e:
+			raise UtilityException(f'failed to move {str(src)} to {str(dst)} due to {type(e).__name__} {str(e)}')
+	
 	@staticmethod
 	def patchFile(filename, replacements):
 		"""
@@ -59,6 +69,26 @@ def patchFile(filename, replacements):
 		
 		Utility.writeFile(filename, patched)
 	
+	@staticmethod
+	def removeDir(path, ignore_errors=False):
+		"""
+		Recursively remove directory tree
+		"""
+		try:
+			shutil.rmtree(path, ignore_errors)
+		except OSError as e:
+			raise UtilityException(f'failed to remove directory {str(path)} due to {type(e).__name__} {str(e)}')
+	
+	@staticmethod
+	def makeDirs(name, mode=0o777, exist_ok=False):
+		"""
+		Makes directory
+		"""
+		try:
+			os.makedirs(name, mode, exist_ok)
+		except OSError as e:
+			raise UtilityException(f'failed to create directory {str(name)} due to {type(e).__name__} {str(e)}')
+	
 	@staticmethod
 	def forwardSlashes(paths):
 		"""

From 05bd9c77bead5785e8ae6b4ca425f242c90e1ead Mon Sep 17 00:00:00 2001
From: sleeptightAnsiC <91839286+sleeptightAnsiC@users.noreply.github.com>
Date: Sun, 24 Mar 2024 13:58:40 +0100
Subject: [PATCH 7/8] fix formatting for assertions and add notes

---
 ue4cli/JsonDataManager.py      |  7 ++++---
 ue4cli/UnrealManagerWindows.py |  2 +-
 ue4cli/Utility.py              | 10 +++++-----
 ue4cli/cli.py                  | 11 ++++++++---
 4 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/ue4cli/JsonDataManager.py b/ue4cli/JsonDataManager.py
index b67fa00..7e94238 100644
--- a/ue4cli/JsonDataManager.py
+++ b/ue4cli/JsonDataManager.py
@@ -16,15 +16,16 @@ def __init__(self, jsonFile):
 
 	def loads(self):
 		"""
-		Wrapper for json.loads which reads owned jsonFile and loads it
-		In case of encountering JSONDecodeError, it will raise UtilityException
+		Reads and loads owned jsonFile
 		"""
 		try:
 			path = self.jsonFile
 			file = Utility.readFile(path)
 			return json.loads(file)
 		except json.JSONDecodeError as e:
-			raise UtilityException(f'failed to load {str(path)} due to {type(e).__name__} {str(e)}')
+			# FIXME: This is the only place outside of Utility class where we use UtilityException.
+			# Not worth to create new Exception class for only one single case, at least not now.
+			raise UtilityException(f'failed to load "{str(path)}" due to: ({type(e).__name__}) {str(e)}')
 	
 	def getKey(self, key):
 		"""
diff --git a/ue4cli/UnrealManagerWindows.py b/ue4cli/UnrealManagerWindows.py
index c11210d..e7a2101 100644
--- a/ue4cli/UnrealManagerWindows.py
+++ b/ue4cli/UnrealManagerWindows.py
@@ -42,7 +42,7 @@ def getGenerateScript(self):
 		except:
 			pass
 		
-		raise UnrealManagerException('could not detect the location of GenerateProjectFiles.bat or UnrealVersionSelector.exe.\nThis typically indicates that .uproject files are not correctly associated with UE4.')
+		raise UnrealManagerException('could not detect the location of GenerateProjectFiles.bat or UnrealVersionSelector.exe. This typically indicates that .uproject files are not correctly associated with UE4.')
 	
 	def getRunUATScript(self):
 		return self.getEngineRoot() + '\\Engine\\Build\\BatchFiles\\RunUAT.bat'
diff --git a/ue4cli/Utility.py b/ue4cli/Utility.py
index d3a06fd..7d7a8ff 100644
--- a/ue4cli/Utility.py
+++ b/ue4cli/Utility.py
@@ -33,7 +33,7 @@ def readFile(filename):
 			with open(filename, 'rb') as f:
 				return f.read().decode('utf-8')
 		except OSError as e:
-			raise UtilityException(f'failed to read file {str(filename)} due to {type(e).__name__} {str(e)}')
+			raise UtilityException(f'failed to read file "{str(filename)}" due to: ({type(e).__name__}) {str(e)}')
 	
 	@staticmethod
 	def writeFile(filename, data):
@@ -44,7 +44,7 @@ def writeFile(filename, data):
 			with open(filename, 'wb') as f:
 				f.write(data.encode('utf-8'))
 		except OSError as e:
-			raise UtilityException(f'failed to write file {str(filename)} due to {type(e).__name__} {str(e)}')
+			raise UtilityException(f'failed to write file "{str(filename)}" due to: ({type(e).__name__}) {str(e)}')
 	
 	@staticmethod
 	def moveFile(src, dst):
@@ -54,7 +54,7 @@ def moveFile(src, dst):
 		try:
 			shutil.move(src, dst)
 		except OSError as e:
-			raise UtilityException(f'failed to move {str(src)} to {str(dst)} due to {type(e).__name__} {str(e)}')
+			raise UtilityException(f'failed to move file from "{str(src)}" to "{str(dst)}" due to: ({type(e).__name__}) {str(e)}')
 	
 	@staticmethod
 	def patchFile(filename, replacements):
@@ -77,7 +77,7 @@ def removeDir(path, ignore_errors=False):
 		try:
 			shutil.rmtree(path, ignore_errors)
 		except OSError as e:
-			raise UtilityException(f'failed to remove directory {str(path)} due to {type(e).__name__} {str(e)}')
+			raise UtilityException(f'failed to remove directory "{str(path)}" due to: ({type(e).__name__}) {str(e)}')
 	
 	@staticmethod
 	def makeDirs(name, mode=0o777, exist_ok=False):
@@ -87,7 +87,7 @@ def makeDirs(name, mode=0o777, exist_ok=False):
 		try:
 			os.makedirs(name, mode, exist_ok)
 		except OSError as e:
-			raise UtilityException(f'failed to create directory {str(name)} due to {type(e).__name__} {str(e)}')
+			raise UtilityException(f'failed to create directory "{str(name)}" due to: ({type(e).__name__}) {str(e)}')
 	
 	@staticmethod
 	def forwardSlashes(paths):
diff --git a/ue4cli/cli.py b/ue4cli/cli.py
index 25261fa..a66fe35 100644
--- a/ue4cli/cli.py
+++ b/ue4cli/cli.py
@@ -202,9 +202,10 @@ def displayHelp():
 		print()
 
 def main():
+	
+	logger = logging.getLogger(__name__)
+	
 	try:
-		logger = logging.getLogger(__name__)
-		
 		# Perform plugin detection and register our detected plugins
 		plugins = PluginManager.getPlugins()
 		for command in plugins:
@@ -224,14 +225,18 @@ def main():
 		if command in SUPPORTED_COMMANDS:
 			SUPPORTED_COMMANDS[command]['action'](manager, args)
 		else:
+			# FIXME: This is the only place outside of UnrealManager... classes where we use UnrealManagerException.
+			# Not worth to create new Exception class for only one single case, at least not now.
 			raise UnrealManagerException('unrecognised command "' + command + '"')
+	
 	except (
 			UnrealManagerException,
 			UtilityException,
 			KeyboardInterrupt,
 			) as e:
-		Utility.printStderr('(' + type(e).__name__ + ')', str(e))
+		Utility.printStderr(f'Error: ({type(e).__name__}) {str(e)}')
 		sys.exit(1)
+	
 	except BaseException as e:
 		Utility.printStderr('Unhandled exception! Crashing...')
 		logging.basicConfig(level=logging.DEBUG)

From e58d718953499b063d196eb145078d10381a933c Mon Sep 17 00:00:00 2001
From: sleeptightAnsiC <91839286+sleeptightAnsiC@users.noreply.github.com>
Date: Sun, 24 Mar 2024 16:38:51 +0100
Subject: [PATCH 8/8] fix: explicitly chain the exception when raising from
 'except' block

https://docs.python.org/3/tutorial/errors.html#exception-chaining
https://github.com/adamrehn/ue4cli/pull/65/files/05bd9c77bead5785e8ae6b4ca425f242c90e1ead#r1536831787
---
 ue4cli/JsonDataManager.py   |  2 +-
 ue4cli/UnrealManagerBase.py | 22 ++++++++++++----------
 ue4cli/Utility.py           | 10 +++++-----
 ue4cli/cli.py               |  2 +-
 4 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/ue4cli/JsonDataManager.py b/ue4cli/JsonDataManager.py
index 7e94238..049f762 100644
--- a/ue4cli/JsonDataManager.py
+++ b/ue4cli/JsonDataManager.py
@@ -25,7 +25,7 @@ def loads(self):
 		except json.JSONDecodeError as e:
 			# FIXME: This is the only place outside of Utility class where we use UtilityException.
 			# Not worth to create new Exception class for only one single case, at least not now.
-			raise UtilityException(f'failed to load "{str(path)}" due to: ({type(e).__name__}) {str(e)}')
+			raise UtilityException(f'failed to load "{str(path)}" due to: ({type(e).__name__}) {str(e)}') from e
 	
 	def getKey(self, key):
 		"""
diff --git a/ue4cli/UnrealManagerBase.py b/ue4cli/UnrealManagerBase.py
index 6c9d301..ff60e6a 100644
--- a/ue4cli/UnrealManagerBase.py
+++ b/ue4cli/UnrealManagerBase.py
@@ -52,7 +52,7 @@ def setEngineRootOverride(self, rootDir):
 		try:
 			self.getEngineVersion()
 		except:
-			raise UnrealManagerException('the specified directory does not appear to contain a valid version of the Unreal Engine.')
+			raise UnrealManagerException('the specified directory does not appear to contain a valid version of the Unreal Engine.') from None
 	
 	def clearEngineRootOverride(self):
 		"""
@@ -96,7 +96,7 @@ def getEngineVersion(self, outputFormat = 'full'):
 		
 		# Verify that the requested output format is valid
 		if outputFormat not in formats:
-			raise UnrealManagerException('unreconised version output format "{}"'.format(outputFormat))
+			raise UnrealManagerException(f'unreconised version output format "{str(outputFormat)}"')
 		
 		return formats[outputFormat]
 	
@@ -176,7 +176,7 @@ def getDescriptor(self, dir):
 			try:
 				return self.getPluginDescriptor(dir)
 			except:
-				raise UnrealManagerException('could not detect an Unreal project or plugin in the directory "{}"'.format(dir))
+				raise UnrealManagerException(f'could not detect an Unreal project or plugin in the directory "{str(dir)}"') from None
 	
 	def isProject(self, descriptor):
 		"""
@@ -355,11 +355,11 @@ def buildDescriptor(self, dir=os.getcwd(), configuration='Development', target='
 		
 		# If the project or plugin is Blueprint-only, there is no C++ code to build
 		if os.path.exists(os.path.join(dir, 'Source')) == False:
-			raise UnrealManagerException('Pure Blueprint {}, nothing to build.'.format(descriptorType))
+			raise UnrealManagerException(f'Pure Blueprint {str(descriptorType)}, nothing to build.')
 		
 		# Verify that the specified build configuration is valid
 		if configuration not in self.validBuildConfigurations():
-			raise UnrealManagerException('invalid build configuration "' + configuration + '"')
+			raise UnrealManagerException(f'invalid build configuration "{str(configuration)}"')
 		
 		# Check if the user specified the `-notools` flag to opt out of building Engine tools when working with source builds
 		unstripped = list(args)
@@ -408,7 +408,7 @@ def packageProject(self, dir=os.getcwd(), configuration='Shipping', extraArgs=[]
 		
 		# Verify that the specified build configuration is valid
 		if configuration not in self.validBuildConfigurations():
-			raise UnrealManagerException('invalid build configuration "' + configuration + '"')
+			raise UnrealManagerException(f'invalid build configuration "{str(configuration)}"')
 		
 		# Strip out the `-NoCompileEditor` flag if the user has specified it, since the Development version
 		# of the Editor modules for the project are needed in order to run the commandlet that cooks content
@@ -538,10 +538,12 @@ def listAutomationTests(self, projectFile):
 		# Detect if the Editor terminated abnormally (i.e. not triggered by `automation quit`)
 		# In Unreal Engine 4.27.0, the exit method changed from RequestExit to RequestExitWithStatus
 		if 'PlatformMisc::RequestExit(' not in logOutput.stdout and 'PlatformMisc::RequestExitWithStatus(' not in logOutput.stdout:
-			raise UnrealManagerException(
-				'failed to retrieve the list of automation tests!' +
-				' stdout was: "{}", stderr was: "{}"'.format(logOutput.stdout, logOutput.stderr)
-			)
+			Utility.printStderr("Warning: abnormal Editor termination detected!")
+			Utility.printStderr("printing stdout..")
+			print(logOutput.stdout)
+			Utility.printStderr("printing stderr..")
+			print(logOutput.stderr)
+			raise UnrealManagerException('failed to retrieve the list of automation tests!')
 		
 		return sorted(list(tests))
 	
diff --git a/ue4cli/Utility.py b/ue4cli/Utility.py
index 7d7a8ff..d8989da 100644
--- a/ue4cli/Utility.py
+++ b/ue4cli/Utility.py
@@ -33,7 +33,7 @@ def readFile(filename):
 			with open(filename, 'rb') as f:
 				return f.read().decode('utf-8')
 		except OSError as e:
-			raise UtilityException(f'failed to read file "{str(filename)}" due to: ({type(e).__name__}) {str(e)}')
+			raise UtilityException(f'failed to read file "{str(filename)}" due to: ({type(e).__name__}) {str(e)}') from e
 	
 	@staticmethod
 	def writeFile(filename, data):
@@ -44,7 +44,7 @@ def writeFile(filename, data):
 			with open(filename, 'wb') as f:
 				f.write(data.encode('utf-8'))
 		except OSError as e:
-			raise UtilityException(f'failed to write file "{str(filename)}" due to: ({type(e).__name__}) {str(e)}')
+			raise UtilityException(f'failed to write file "{str(filename)}" due to: ({type(e).__name__}) {str(e)}') from e
 	
 	@staticmethod
 	def moveFile(src, dst):
@@ -54,7 +54,7 @@ def moveFile(src, dst):
 		try:
 			shutil.move(src, dst)
 		except OSError as e:
-			raise UtilityException(f'failed to move file from "{str(src)}" to "{str(dst)}" due to: ({type(e).__name__}) {str(e)}')
+			raise UtilityException(f'failed to move file from "{str(src)}" to "{str(dst)}" due to: ({type(e).__name__}) {str(e)}') from e
 	
 	@staticmethod
 	def patchFile(filename, replacements):
@@ -77,7 +77,7 @@ def removeDir(path, ignore_errors=False):
 		try:
 			shutil.rmtree(path, ignore_errors)
 		except OSError as e:
-			raise UtilityException(f'failed to remove directory "{str(path)}" due to: ({type(e).__name__}) {str(e)}')
+			raise UtilityException(f'failed to remove directory "{str(path)}" due to: ({type(e).__name__}) {str(e)}') from e
 	
 	@staticmethod
 	def makeDirs(name, mode=0o777, exist_ok=False):
@@ -87,7 +87,7 @@ def makeDirs(name, mode=0o777, exist_ok=False):
 		try:
 			os.makedirs(name, mode, exist_ok)
 		except OSError as e:
-			raise UtilityException(f'failed to create directory "{str(name)}" due to: ({type(e).__name__}) {str(e)}')
+			raise UtilityException(f'failed to create directory "{str(name)}" due to: ({type(e).__name__}) {str(e)}') from e
 	
 	@staticmethod
 	def forwardSlashes(paths):
diff --git a/ue4cli/cli.py b/ue4cli/cli.py
index a66fe35..df88040 100644
--- a/ue4cli/cli.py
+++ b/ue4cli/cli.py
@@ -227,7 +227,7 @@ def main():
 		else:
 			# FIXME: This is the only place outside of UnrealManager... classes where we use UnrealManagerException.
 			# Not worth to create new Exception class for only one single case, at least not now.
-			raise UnrealManagerException('unrecognised command "' + command + '"')
+			raise UnrealManagerException(f'unrecognised command "{str(command)}"') from None
 	
 	except (
 			UnrealManagerException,