Fix new flake8 warnings

python/servo/build_commands.py

@@ -46,7 +46,7 @@ def notify_linux(title, text):
         notify_obj = bus.get_object("org.freedesktop.Notifications", "/org/freedesktop/Notifications")
         method = notify_obj.get_dbus_method("Notify", "org.freedesktop.Notifications")
         method(title, 0, "", text, "", [], {"transient": True}, -1)
-    except:
+    except ImportError:
         raise Exception("Optional Python module 'dbus' is not installed.")
 
 
@@ -55,7 +55,7 @@ def notify_win(title, text):
         from servo.win32_toast import WindowsToast
         w = WindowsToast()
         w.balloon_tip(title, text)
-    except:
+    except WindowsError:
         from ctypes import Structure, windll, POINTER, sizeof
         from ctypes.wintypes import DWORD, HANDLE, WINFUNCTYPE, BOOL, UINT
 
@@ -920,7 +920,7 @@ def package_gstreamer_dlls(env, servo_exe_dir, target, uwp):
     for gst_lib in gst_dlls:
         try:
             shutil.copy(path.join(gst_root, "bin", gst_lib), servo_exe_dir)
-        except:
+        except FileNotFoundError:
             missing += [str(gst_lib)]
 
     for gst_lib in missing:
@@ -976,7 +976,7 @@ def package_gstreamer_dlls(env, servo_exe_dir, target, uwp):
     for gst_lib in gst_dlls:
         try:
             shutil.copy(path.join(gst_plugin_path, gst_lib), servo_exe_dir)
-        except:
+        except FileNotFoundError:
             missing += [str(gst_lib)]
 
     for gst_lib in missing:

python/servo/command_base.py

@@ -487,7 +487,7 @@ class CommandBase(object):
             print("Could not fetch the available nightly versions from the repository : {}".format(
                 e.reason))
             sys.exit(1)
-        except AttributeError as e:
+        except AttributeError:
             print("Could not fetch a nightly version for date {} and platform {}".format(
                 nightly_date, os_prefix))
             sys.exit(1)
@@ -517,8 +517,8 @@ class CommandBase(object):
         else:
             print("The nightly {} does not exist yet, downloading it.".format(
                 destination_file))
-            download_file(destination_file, NIGHTLY_REPOSITORY_URL +
-                          file_to_download, destination_file)
+            download_file(destination_file, NIGHTLY_REPOSITORY_URL
+                          + file_to_download, destination_file)
 
         # Extract the downloaded nightly version
         if os.path.isdir(destination_folder):
@@ -537,7 +537,7 @@ class CommandBase(object):
         try:
             if check_gstreamer_lib():
                 return False
-        except:
+        except subprocess.SubprocessError:
             # Some systems don't have pkg-config; we can't probe in this case
             # and must hope for the best
             return False
@@ -552,7 +552,7 @@ class CommandBase(object):
                 raise Exception("Your system's gstreamer libraries are out of date \
 (we need at least 1.16). Please run ./mach bootstrap-gstreamer")
         else:
-                raise Exception("Your system's gstreamer libraries are out of date \
+            raise Exception("Your system's gstreamer libraries are out of date \
 (we need at least 1.16). If you're unable to \
 install them, let us know by filing a bug!")
         return False
@@ -858,9 +858,9 @@ install them, let us know by filing a bug!")
     def pick_media_stack(self, media_stack, target):
         if not(media_stack):
             if (
-                    not(target) or
-                    ("armv7" in target and "android" in target) or
-                    ("x86_64" in target)
+                    not(target)
+                    or ("armv7" in target and "android" in target)
+                    or ("x86_64" in target)
             ):
                 media_stack = "gstreamer"
             else:
@@ -1032,7 +1032,7 @@ install them, let us know by filing a bug!")
                 print()
                 sys.exit(1)
             raise
-        version = tuple(map(int, re.match(b"rustup (\d+)\.(\d+)\.(\d+)", version_line).groups()))
+        version = tuple(map(int, re.match(br"rustup (\d+)\.(\d+)\.(\d+)", version_line).groups()))
         version_needed = (1, 21, 0)
         if version < version_needed:
             print("rustup is at version %s.%s.%s, Servo requires %s.%s.%s or more recent." % (version + version_needed))
@@ -1069,8 +1069,8 @@ install them, let us know by filing a bug!")
 
 def find_highest_msvc_version_ext():
     def vswhere(args):
-        program_files = (os.environ.get('PROGRAMFILES(X86)') or
-                         os.environ.get('PROGRAMFILES'))
+        program_files = (os.environ.get('PROGRAMFILES(X86)')
+                         or os.environ.get('PROGRAMFILES'))
         if not program_files:
             return []
         vswhere = os.path.join(program_files, 'Microsoft Visual Studio',
@@ -1107,8 +1107,8 @@ def find_highest_msvc_version():
 
     versions = sorted(find_highest_msvc_version_ext(), key=lambda tup: float(tup[1]))
     if not versions:
-        print("Can't find MSBuild.exe installation under %s. Please set the VSINSTALLDIR and VisualStudioVersion" +
-              " environment variables" % base_vs_path)
+        print("Can't find MSBuild.exe installation under %s. Please set the VSINSTALLDIR and VisualStudioVersion"
+              + " environment variables" % base_vs_path)
         sys.exit(1)
     return versions[0]