Fixed code quality issues using deepsource (#1300)

- Added .deepsource.toml to fix bug risks

- Remove unnecessary use of comprehension

- Use `os.environ.copy()` to copy the environment variables

- Remove unnecessary return statement

- Use `sys.exit()` calls

.deepsource.toml

@@ -0,0 +1,25 @@
+version = 1
+
+test_patterns = ["tests/**"]
+
+[[analyzers]]
+name = "python"
+enabled = true
+
+  [analyzers.meta]
+  runtime_version = "3.x.x"
+
+
+[[analyzers]]
+name = "docker"
+enabled = true
+
+  [analyzers.meta]
+  dockerfile_paths = [
+    "dockerfile_dev",
+    "dockerfile_prod"
+  ]
+
+[[analyzers]]
+name = "ruby"
+enabled = true

buildozer/__init__.py

@@ -253,7 +253,7 @@ class Buildozer:
 
     def cmd(self, command, **kwargs):
         # prepare the environ, based on the system + our own env
-        env = copy(environ)
+        env = environ.copy()
         env.update(self.environ)
 
         # prepare the process
@@ -360,7 +360,7 @@ class Buildozer:
         from pexpect import spawnu
 
         # prepare the environ, based on the system + our own env
-        env = copy(environ)
+        env = environ.copy()
         env.update(self.environ)
 
         # prepare the process
@@ -935,8 +935,7 @@ class Buildozer:
 
             if not meth.__doc__:
                 continue
-            doc = [x for x in
-                    meth.__doc__.strip().splitlines()][0].strip()
+            doc = list(meth.__doc__.strip().splitlines())[0].strip()
             print('  {0:<18} {1}'.format(name, doc))
 
         print('')

buildozer/targets/android.py

@@ -759,7 +759,7 @@ class TargetAndroid(Target):
         except IOError:
             self.buildozer.error('Failed to read python-for-android setup.py at {}'.format(
                 join(self.p4a_dir, 'setup.py')))
-            exit(1)
+            sys.exit(1)
         pip_deps = []
         for dep in deps:
             pip_deps.append("'{}'".format(dep))
@@ -1287,7 +1287,7 @@ class TargetAndroid(Target):
                 self.buildozer.error(
                     'Invalid library reference (path not found): {}'.format(
                         cref))
-                exit(1)
+                sys.exit(1)
             # get a relative path from the project file
             ref = relpath(ref, realpath(expanduser(dist_dir)))
             # ensure the reference exists

buildozer/targets/osx.py

@@ -55,7 +55,7 @@ class TargetOSX(Target):
                         "Unable to download the Kivy App. Check osx.kivy_version in your buildozer.spec, and verify "
                         "Kivy servers are accessible. http://kivy.org/downloads/")
                     check_call(("rm", "Kivy{}.dmg".format(py_branch)), cwd=cwd)
-                    exit(1)
+                    sys.exit(1)
 
             self.buildozer.info('Extracting and installing Kivy...')
             check_call(('hdiutil', 'attach', cwd + '/Kivy{}.dmg'.format(py_branch)))
@@ -76,8 +76,6 @@ class TargetOSX(Target):
         else:
             self.download_kivy(kivy_app_dir, py_branch)
 
-        return
-
     def check_requirements(self):
         self.ensure_sdk()
         self.ensure_kivyapp()
@@ -90,7 +88,7 @@ class TargetOSX(Target):
                 len(errors)))
             for error in errors:
                 print(error)
-            exit(1)
+            sys.exit(1)
         # check
 
     def build_package(self):
@@ -177,7 +175,7 @@ class TargetOSX(Target):
         if not args:
             self.buildozer.error('Missing target command')
             self.buildozer.usage()
-            exit(1)
+            sys.exit(1)
 
         result = []
         last_command = []
@@ -191,7 +189,7 @@ class TargetOSX(Target):
                 if not last_command:
                     self.buildozer.error('Argument passed without a command')
                     self.buildozer.usage()
-                    exit(1)
+                    sys.exit(1)
                 last_command.append(arg)
         if last_command:
             result.append(last_command)
@@ -202,7 +200,7 @@ class TargetOSX(Target):
             command, args = item[0], item[1:]
             if not hasattr(self, 'cmd_{0}'.format(command)):
                 self.buildozer.error('Unknown command {0}'.format(command))
-                exit(1)
+                sys.exit(1)
 
             func = getattr(self, 'cmd_{0}'.format(command))