chore: refactor code quality issues

- Refactor complex statement to use if expression.
- Fix dangerous default argument.
- Remove unused imports and reimported modules.
- Refactor unnecessary use of list comprehension.
- Add .deepsource.toml file for continuous analysis on bug risks/performance/code-quality issues on new changes.

.deepsource.toml

+version = 1
+
+test_patterns = [
+    "zc.recipe.egg_/src/zc/recipe/egg/tests.py",
+    "src/zc/buildout/tests/**"
+]
+
+exclude_patterns = ["builds/**"]
+
+[[analyzers]]
+name = "python"
+enabled = true
+
+  [analyzers.meta]
+  runtime_version = "3.x.x"
\ No newline at end of file

dev.py

@@ -25,7 +25,7 @@ if sys.version_info > (3, ) and sys.version_info < (3, 5):
     raise SystemError("No support for Python 3.x under 3.5.")
 
 
-import os, shutil, sys, subprocess, tempfile
+import os, shutil, subprocess, tempfile
 
 for d in 'eggs', 'develop-eggs', 'bin', 'parts':
     if not os.path.exists(d):

src/zc/buildout/download.py

@@ -80,8 +80,10 @@ class Download(object):
 
     """
 
-    def __init__(self, options={}, cache=-1, namespace=None,
+    def __init__(self, options=None, cache=-1, namespace=None,
                  offline=-1, fallback=False, hash_name=False, logger=None):
+        if options is None:
+            options = {}
         self.directory = options.get('directory', '')
         self.cache = cache
         if cache == -1:

src/zc/buildout/easy_install.py

@@ -1742,7 +1742,7 @@ def make_egg_after_pip_install(dest, distinfo_dir):
                     shutil.rmtree(bin_dir)
 
     # Make properly named new egg dir
-    distro = [d for d in pkg_resources.find_distributions(dest)][0]
+    distro = list(pkg_resources.find_distributions(dest))[0]
     egg_name = distro.egg_name() + '.egg'
     egg_dir = os.path.join(dest, egg_name)
     os.mkdir(egg_dir)

src/zc/buildout/testing.py

@@ -621,7 +621,6 @@ def run_buildout(command):
     # Make sure we don't get .buildout
     os.environ['HOME'] = os.path.join(os.getcwd(), 'home')
     args = command.split()
-    import pkg_resources
     buildout = pkg_resources.load_entry_point(
         'zc.buildout', 'console_scripts', args[0])
     buildout(args[1:])

src/zc/buildout/tests/__init__.py

@@ -30,7 +30,7 @@ def create_sample_eggs(test, executable=sys.executable):
 
         for i in (0, 1, 2):
             write(tmp, 'eggrecipedemoneeded.py', 'y=%s\ndef f():\n  pass' % i)
-            rc1 = i==2 and 'rc1' or ''
+            rc1 = 'rc1' if i==2 else ''
             write(
                 tmp, 'setup.py',
                 "from setuptools import setup\n"
@@ -81,7 +81,7 @@ def create_sample_eggs(test, executable=sys.executable):
                 'def main():\n'
                 '   print_(x, eggrecipedemoneeded.y)\n'
                 % i)
-            rc1 = i==4 and 'rc1' or ''
+            rc1 = 'rc1' if i==4 else ''
             write(
                 tmp, 'setup.py',
                 "from setuptools import setup\n"
@@ -175,7 +175,7 @@ MOD_INIT(extdemo)
 }
 """
 
-extdemo_c = sys.version_info[0] < 3 and extdemo_c2 or extdemo_c3
+extdemo_c = extdemo_c2 if sys.version_info[0] < 3 else extdemo_c3
 
 extdemo_setup_py = r"""
 import os, sys

src/zc/buildout/tests/test_all.py

@@ -384,7 +384,9 @@ setup(name=%r, version=%r,
       )
 """
 
-def make_dist_that_requires(dest, name, requires=[], version=1, egg=''):
+def make_dist_that_requires(dest, name, requires=None, version=1, egg=''):
+    if requires is None:
+        requires = []
     os.mkdir(os.path.join(dest, name))
     with open(os.path.join(dest, name, 'setup.py'), 'w') as f:
         f.write(

zc.recipe.egg_/src/zc/recipe/egg/egg.py

@@ -15,10 +15,8 @@
 """
 
 import copy
-import glob
 import logging
 import os
-import pkg_resources
 import re
 import sys
 import zc.buildout.easy_install

zc.recipe.egg_/src/zc/recipe/egg/tests.py

@@ -16,8 +16,6 @@ from zope.testing import renormalizing
 import doctest
 import os
 import re
-import shutil
-import sys
 import zc.buildout.tests
 import zc.buildout.testing
 from zc.buildout import WINDOWS