Rollup merge of rust-lang#68947 - chrissimpkins:python-fmt, r=alexcri…

…chton

Python script PEP8 style guide space formatting and minor Python source cleanup

This PR includes the following changes in the Python sources based on a flake8 3.7.9 (mccabe: 0.6.1, pycodestyle: 2.5.0, pyflakes: 2.1.1) CPython 3.7.6 on Darwin lint:

- PEP8 style guide spacing updates *without* line length changes
- removal of unused local variable assignments in context managers and exception handling
- removal of unused Python import statements
- removal of unnecessary semicolons

src/bootstrap/bootstrap.py

@@ -80,7 +80,7 @@ def _download(path, url, probably_big, verbose, exception):
             option = "-s"
         run(["curl", option,
              "-y", "30", "-Y", "10",    # timeout if speed is < 10 bytes/sec for > 30 seconds
-             "--connect-timeout", "30", # timeout if cannot connect within 30 seconds
+             "--connect-timeout", "30",  # timeout if cannot connect within 30 seconds
              "--retry", "3", "-Sf", "-o", path, url],
             verbose=verbose,
             exception=exception)
@@ -332,7 +332,6 @@ def __init__(self):
         self.use_vendored_sources = ''
         self.verbose = False
 
-
     def download_stage0(self):
         """Fetch the build system for Rust, written in Rust
 
@@ -351,7 +350,7 @@ def support_xz():
             try:
                 with tempfile.NamedTemporaryFile(delete=False) as temp_file:
                     temp_path = temp_file.name
-                with tarfile.open(temp_path, "w:xz") as tar:
+                with tarfile.open(temp_path, "w:xz"):
                     pass
                 return True
             except tarfile.CompressionError:
@@ -825,7 +824,7 @@ def check_vendored_status(self):
                 if not os.path.exists(vendor_dir):
                     print('error: vendoring required, but vendor directory does not exist.')
                     print('       Run `cargo vendor` without sudo to initialize the '
-                        'vendor directory.')
+                          'vendor directory.')
                     raise Exception("{} not found".format(vendor_dir))
 
         if self.use_vendored_sources:
@@ -839,7 +838,7 @@ def check_vendored_status(self):
                     "\n"
                     "[source.vendored-sources]\n"
                     "directory = '{}/vendor'\n"
-                .format(self.rust_root))
+                    .format(self.rust_root))
         else:
             if os.path.exists('.cargo'):
                 shutil.rmtree('.cargo')

src/bootstrap/configure.py

@@ -393,11 +393,12 @@ def set(key, value):
 
 
 def is_number(value):
-  try:
-    float(value)
-    return True
-  except ValueError:
-    return False
+    try:
+        float(value)
+        return True
+    except ValueError:
+        return False
+
 
 # Here we walk through the constructed configuration we have from the parsed
 # command line arguments. We then apply each piece of configuration by

src/ci/cpu-usage-over-time.py

@@ -148,11 +148,11 @@ def idle_since(self, prev):
     print('unknown platform', sys.platform)
     sys.exit(1)
 
-cur_state = State();
+cur_state = State()
 print("Time,Idle")
 while True:
-    time.sleep(1);
-    next_state = State();
+    time.sleep(1)
+    next_state = State()
     now = datetime.datetime.utcnow().isoformat()
     idle = next_state.idle_since(cur_state)
     print("%s,%s" % (now, idle))

src/etc/debugger_pretty_printers_common.py

@@ -212,7 +212,6 @@ def __classify_struct(self):
         # REGULAR STRUCT
         return TYPE_KIND_REGULAR_STRUCT
 
-
     def __classify_union(self):
         assert self.get_dwarf_type_kind() == DWARF_TYPE_CODE_UNION
 
@@ -233,7 +232,6 @@ def __classify_union(self):
         else:
             return TYPE_KIND_REGULAR_UNION
 
-
     def __conforms_to_field_layout(self, expected_fields):
         actual_fields = self.get_fields()
         actual_field_count = len(actual_fields)
@@ -363,6 +361,7 @@ def extract_tail_head_ptr_and_cap_from_std_vecdeque(vec_val):
     assert data_ptr.type.get_dwarf_type_kind() == DWARF_TYPE_CODE_PTR
     return (tail, head, data_ptr, capacity)
 
+
 def extract_length_and_ptr_from_slice(slice_val):
     assert (slice_val.type.get_type_kind() == TYPE_KIND_SLICE or
             slice_val.type.get_type_kind() == TYPE_KIND_STR_SLICE)
@@ -376,8 +375,10 @@ def extract_length_and_ptr_from_slice(slice_val):
     assert data_ptr.type.get_dwarf_type_kind() == DWARF_TYPE_CODE_PTR
     return (length, data_ptr)
 
+
 UNQUALIFIED_TYPE_MARKERS = frozenset(["(", "[", "&", "*"])
 
+
 def extract_type_name(qualified_type_name):
     """Extracts the type name from a fully qualified path"""
     if qualified_type_name[0] in UNQUALIFIED_TYPE_MARKERS:
@@ -393,6 +394,7 @@ def extract_type_name(qualified_type_name):
     else:
         return qualified_type_name[index + 2:]
 
+
 try:
     compat_str = unicode  # Python 2
 except NameError:

src/etc/dec2flt_table.py

@@ -14,7 +14,6 @@
 even larger, and it's already uncomfortably large (6 KiB).
 """
 from __future__ import print_function
-import sys
 from math import ceil, log
 from fractions import Fraction
 from collections import namedtuple
@@ -82,6 +81,7 @@ def error(f, e, z):
     ulp_err = abs_err / Fraction(2) ** z.exp
     return float(ulp_err)
 
+
 HEADER = """
 //! Tables of approximations of powers of ten.
 //! DO NOT MODIFY: Generated by `src/etc/dec2flt_table.py`

src/etc/gdb_rust_pretty_printing.py

@@ -9,7 +9,7 @@
 if sys.version_info[0] >= 3:
     xrange = range
 
-rust_enabled = 'set language rust' in gdb.execute('complete set language ru', to_string = True)
+rust_enabled = 'set language rust' in gdb.execute('complete set language ru', to_string=True)
 
 # The btree pretty-printers fail in a confusing way unless
 # https://sourceware.org/bugzilla/show_bug.cgi?id=21763 is fixed.
@@ -21,9 +21,10 @@
     if int(_match.group(1)) > 8 or (int(_match.group(1)) == 8 and int(_match.group(2)) >= 1):
         gdb_81 = True
 
-#===============================================================================
+# ===============================================================================
 # GDB Pretty Printing Module for Rust
-#===============================================================================
+# ===============================================================================
+
 
 class GdbType(rustpp.Type):
 
@@ -133,39 +134,39 @@ def rust_pretty_printer_lookup_function(gdb_val):
 
     if type_kind == rustpp.TYPE_KIND_REGULAR_STRUCT:
         return RustStructPrinter(val,
-                                 omit_first_field = False,
-                                 omit_type_name = False,
-                                 is_tuple_like = False)
+                                 omit_first_field=False,
+                                 omit_type_name=False,
+                                 is_tuple_like=False)
 
     if type_kind == rustpp.TYPE_KIND_STRUCT_VARIANT:
         return RustStructPrinter(val,
-                                 omit_first_field = True,
-                                 omit_type_name = False,
-                                 is_tuple_like = False)
+                                 omit_first_field=True,
+                                 omit_type_name=False,
+                                 is_tuple_like=False)
 
     if type_kind == rustpp.TYPE_KIND_STR_SLICE:
         return RustStringSlicePrinter(val)
 
     if type_kind == rustpp.TYPE_KIND_TUPLE:
         return RustStructPrinter(val,
-                                 omit_first_field = False,
-                                 omit_type_name = True,
-                                 is_tuple_like = True)
+                                 omit_first_field=False,
+                                 omit_type_name=True,
+                                 is_tuple_like=True)
 
     if type_kind == rustpp.TYPE_KIND_TUPLE_STRUCT:
         return RustStructPrinter(val,
-                                 omit_first_field = False,
-                                 omit_type_name = False,
-                                 is_tuple_like = True)
+                                 omit_first_field=False,
+                                 omit_type_name=False,
+                                 is_tuple_like=True)
 
     if type_kind == rustpp.TYPE_KIND_CSTYLE_VARIANT:
         return RustCStyleVariantPrinter(val.get_child_at_index(0))
 
     if type_kind == rustpp.TYPE_KIND_TUPLE_VARIANT:
         return RustStructPrinter(val,
-                                 omit_first_field = True,
-                                 omit_type_name = False,
-                                 is_tuple_like = True)
+                                 omit_first_field=True,
+                                 omit_type_name=False,
+                                 is_tuple_like=True)
 
     if type_kind == rustpp.TYPE_KIND_SINGLETON_ENUM:
         variant = get_field_at_index(gdb_val, 0)
@@ -189,9 +190,9 @@ def rust_pretty_printer_lookup_function(gdb_val):
     return None
 
 
-#=------------------------------------------------------------------------------
+# =------------------------------------------------------------------------------
 # Pretty Printer Classes
-#=------------------------------------------------------------------------------
+# =------------------------------------------------------------------------------
 class RustEmptyPrinter(object):
     def __init__(self, val):
         self.__val = val
@@ -355,6 +356,7 @@ def children_of_node(boxed_node, height, want_values):
             else:
                 yield keys[i]['value']['value']
 
+
 class RustStdBTreeSetPrinter(object):
     def __init__(self, val):
         self.__val = val
@@ -429,6 +431,7 @@ def to_string(self):
     def display_hint(self):
         return "string"
 
+
 class RustCStyleVariantPrinter(object):
     def __init__(self, val):
         assert val.type.get_dwarf_type_kind() == rustpp.DWARF_TYPE_CODE_ENUM

src/etc/generate-deriving-span-tests.py

@@ -8,7 +8,8 @@
 sample usage: src/etc/generate-deriving-span-tests.py
 """
 
-import os, stat
+import os
+import stat
 
 TEST_DIR = os.path.abspath(
     os.path.join(os.path.dirname(__file__), '../test/ui/derives/'))
@@ -56,15 +57,17 @@
 
 ENUM_TUPLE, ENUM_STRUCT, STRUCT_FIELDS, STRUCT_TUPLE = range(4)
 
+
 def create_test_case(type, trait, super_traits, error_count):
     string = [ENUM_STRING, ENUM_STRUCT_VARIANT_STRING, STRUCT_STRING, STRUCT_TUPLE_STRING][type]
     all_traits = ','.join([trait] + super_traits)
     super_traits = ','.join(super_traits)
     error_deriving = '#[derive(%s)]' % super_traits if super_traits else ''
 
     errors = '\n'.join('//~%s ERROR' % ('^' * n) for n in range(error_count))
-    code = string.format(traits = all_traits, errors = errors)
-    return TEMPLATE.format(error_deriving=error_deriving, code = code)
+    code = string.format(traits=all_traits, errors=errors)
+    return TEMPLATE.format(error_deriving=error_deriving, code=code)
+
 
 def write_file(name, string):
     test_file = os.path.join(TEST_DIR, 'derives-span-%s.rs' % name)
@@ -86,10 +89,10 @@ def write_file(name, string):
 
 traits = {
     'Default': (STRUCT, [], 1),
-    'FromPrimitive': (0, [], 0), # only works for C-like enums
+    'FromPrimitive': (0, [], 0),  # only works for C-like enums
 
-    'Decodable': (0, [], 0), # FIXME: quoting gives horrible spans
-    'Encodable': (0, [], 0), # FIXME: quoting gives horrible spans
+    'Decodable': (0, [], 0),  # FIXME: quoting gives horrible spans
+    'Encodable': (0, [], 0),  # FIXME: quoting gives horrible spans
 }
 
 for (trait, supers, errs) in [('Clone', [], 1),

src/etc/generate-keyword-tests.py

@@ -11,7 +11,6 @@
 
 import sys
 import os
-import datetime
 import stat