Reland "mojo: drop py2 compatibility"

This reverts commit 28c3f06318.

Reason for revert:
include fix for presubmit.

Original change's description:
> Revert "mojo: drop py2 compatibility"
>
> This reverts commit 42775cc82e.
>
> Reason for revert: causes http://crbug.com/1315672
>
> Original change's description:
> > mojo: drop py2 compatibility
> >
> > Python2 is not used for Chromium build now.
> >
> > Bug: 1309804
> > Change-Id: I77b767ae72d82faaaa00dd1cce15e73f890ec568
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3581234
> > Auto-Submit: Takuto Ikuta <tikuta@chromium.org>
> > Reviewed-by: Ken Rockot <rockot@google.com>
> > Commit-Queue: Ken Rockot <rockot@google.com>
> > Cr-Commit-Position: refs/heads/main@{#991607}
>
> Bug: 1309804
> Change-Id: Iee05768e1a785a2273af57854c4ffde51922254a
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3584231
> Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
> Auto-Submit: Andrey Kosyakov <caseq@chromium.org>
> Commit-Queue: Lei Zhang <thestig@chromium.org>
> Owners-Override: Lei Zhang <thestig@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#991666}

Bug: 1309804
Fixed: 1315672
Change-Id: Ib6150ca75c2f06607b73ae09a3f0864ebc92cdbe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3583686
Auto-Submit: Takuto Ikuta <tikuta@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/main@{#991868}

PRESUBMIT.py

@@ -5499,7 +5499,7 @@ def CheckStableMojomChanges(input_api, output_api):
         })
 
     process = input_api.subprocess.Popen([
-        input_api.python_executable,
+        input_api.python3_executable,
         input_api.os_path.join(
             input_api.PresubmitLocalPath(), 'mojo', 'public', 'tools', 'mojom',
             'check_stable_mojom_compatibility.py'), '--src-root',

PRESUBMIT_test_mocks.py

@@ -70,6 +70,7 @@ class MockInputApi(object):
     self.os_path = os.path
     self.platform = sys.platform
     self.python_executable = sys.executable
+    self.python3_executable = sys.executable
     self.platform = sys.platform
     self.subprocess = subprocess
     self.sys = sys

mojo/public/tools/bindings/generators/mojom_java_generator.py

@@ -28,11 +28,6 @@ sys.path.insert(
                  os.pardir, os.pardir, 'build', 'android', 'gyp'))
 from util import build_utils
 
-# TODO(crbug.com/1174969): Remove this once Python2 is obsoleted.
-if sys.version_info.major != 2:
-  basestring = str
-  long = int
-
 GENERATOR_PREFIX = 'java'
 
 _spec_to_java_type = {
@@ -149,7 +144,7 @@ def GetInterfaceResponseName(method):
   return UpperCamelCase(method.name) + '_Response'
 
 def ParseStringAttribute(attribute):
-  assert isinstance(attribute, basestring)
+  assert isinstance(attribute, str)
   return attribute
 
 def GetJavaTrueFalse(value):
@@ -338,7 +333,7 @@ def ExpressionToText(context, token, kind_spec=''):
     return _TranslateNamedValue(token)
   if kind_spec.startswith('i') or kind_spec.startswith('u'):
     number = ast.literal_eval(token.lstrip('+ '))
-    if not isinstance(number, (int, long)):
+    if not isinstance(number, int):
       raise ValueError('got unexpected type %r for int literal %r' % (
           type(number), token))
     # If the literal is too large to fit a signed long, convert it to the

mojo/public/tools/bindings/generators/mojom_js_generator.py

@@ -8,12 +8,9 @@ import mojom.generate.module as mojom
 import mojom.generate.pack as pack
 import os
 import sys
+import urllib.request
 from mojom.generate.template_expander import UseJinja
 
-if sys.version_info.major == 2:
-  import urllib as urllib_request
-else:
-  import urllib.request as urllib_request
 
 _kind_to_javascript_default_value = {
     mojom.BOOL: "false",
@@ -250,7 +247,7 @@ def GetArrayExpectedDimensionSizes(kind):
 
 
 def GetRelativeUrl(module, base_module):
-  return urllib_request.pathname2url(
+  return urllib.request.pathname2url(
       os.path.relpath(module.path, os.path.dirname(base_module.path)))
 
 
@@ -448,7 +445,7 @@ class Generator(generator.Generator):
                               "mojom-webui/%s-webui.js" % self.module.path)
 
   def _GetRelativePath(self, path):
-    relpath = urllib_request.pathname2url(
+    relpath = urllib.request.pathname2url(
         os.path.relpath(path, os.path.dirname(self.module.path)))
     if relpath.startswith('.') or relpath.startswith('/'):
       return relpath
@@ -1059,7 +1056,7 @@ class Generator(generator.Generator):
               return s[len(prefix):]
             return s
 
-          import_path = urllib_request.pathname2url(
+          import_path = urllib.request.pathname2url(
               os.path.relpath(
                   strip_prefix(import_path, _SHARED_MODULE_PREFIX),
                   strip_prefix(this_module_path, _SHARED_MODULE_PREFIX)))

mojo/public/tools/bindings/generators/mojom_mojolpm_generator.py

@@ -41,12 +41,6 @@ _kind_to_cpp_proto_type = {
 }
 
 
-def _IsStrOrUnicode(x):
-  if sys.version_info[0] < 3:
-    return isinstance(x, (unicode, str))
-  return isinstance(x, str)
-
-
 class _NameFormatter(CppNameFormatter):
   """A formatter for the names of kinds or values."""
 
@@ -451,7 +445,7 @@ class Generator(CppGenerator):
       if field.name == 'MAX':
         continue
       if field.value:
-        if _IsStrOrUnicode(field.value):
+        if isinstance(field.value, str):
           if field.value in values:
             return True
           values.add(field.value)

mojo/public/tools/mojom/mojom/generate/module.py

@@ -12,11 +12,7 @@
 # method = interface.AddMethod('Tat', 0)
 # method.AddParameter('baz', 0, mojom.INT32)
 
-import sys
-if sys.version_info.major == 2:
-  import cPickle as pickle
-else:
-  import pickle
+import pickle
 from uuid import UUID
 
 

mojo/public/tools/mojom/mojom/generate/translate.py

@@ -12,19 +12,12 @@ already been parsed and converted to ASTs before.
 import itertools
 import os
 import re
-import sys
 
 from mojom.generate import generator
 from mojom.generate import module as mojom
 from mojom.parse import ast
 
 
-def _IsStrOrUnicode(x):
-  if sys.version_info[0] < 3:
-    return isinstance(x, (unicode, str))
-  return isinstance(x, str)
-
-
 def _DuplicateName(values):
   """Returns the 'mojom_name' of the first entry in |values| whose 'mojom_name'
   has already been encountered. If there are no duplicates, returns None."""
@@ -572,7 +565,7 @@ def _ResolveNumericEnumValues(enum):
       prev_value += 1
 
     # Integral value (e.g: BEGIN = -0x1).
-    elif _IsStrOrUnicode(field.value):
+    elif isinstance(field.value, str):
       prev_value = int(field.value, 0)
 
     # Reference to a previous enum value (e.g: INIT = BEGIN).

mojo/public/tools/mojom/mojom/parse/ast.py

@@ -9,15 +9,6 @@
 # failures, especially for more complex types.
 
 
-import sys
-
-
-def _IsStrOrUnicode(x):
-  if sys.version_info[0] < 3:
-    return isinstance(x, (unicode, str))
-  return isinstance(x, str)
-
-
 class NodeBase(object):
   """Base class for nodes in the AST."""
 
@@ -96,7 +87,7 @@ class Definition(NodeBase):
   include parameter definitions.) This class is meant to be subclassed."""
 
   def __init__(self, mojom_name, **kwargs):
-    assert _IsStrOrUnicode(mojom_name)
+    assert isinstance(mojom_name, str)
     NodeBase.__init__(self, **kwargs)
     self.mojom_name = mojom_name
 
@@ -108,7 +99,7 @@ class Attribute(NodeBase):
   """Represents an attribute."""
 
   def __init__(self, key, value, **kwargs):
-    assert _IsStrOrUnicode(key)
+    assert isinstance(key, str)
     super(Attribute, self).__init__(**kwargs)
     self.key = key
     self.value = value
@@ -131,10 +122,10 @@ class Const(Definition):
   def __init__(self, mojom_name, attribute_list, typename, value, **kwargs):
     assert attribute_list is None or isinstance(attribute_list, AttributeList)
     # The typename is currently passed through as a string.
-    assert _IsStrOrUnicode(typename)
+    assert isinstance(typename, str)
     # The value is either a literal (currently passed through as a string) or a
     # "wrapped identifier".
-    assert _IsStrOrUnicode or isinstance(value, tuple)
+    assert isinstance(value, (tuple, str))
     super(Const, self).__init__(mojom_name, **kwargs)
     self.attribute_list = attribute_list
     self.typename = typename
@@ -170,7 +161,7 @@ class EnumValue(Definition):
     # The optional value is either an int (which is current a string) or a
     # "wrapped identifier".
     assert attribute_list is None or isinstance(attribute_list, AttributeList)
-    assert value is None or _IsStrOrUnicode(value) or isinstance(value, tuple)
+    assert value is None or isinstance(value, (tuple, str))
     super(EnumValue, self).__init__(mojom_name, **kwargs)
     self.attribute_list = attribute_list
     self.value = value
@@ -193,7 +184,7 @@ class Import(NodeBase):
 
   def __init__(self, attribute_list, import_filename, **kwargs):
     assert attribute_list is None or isinstance(attribute_list, AttributeList)
-    assert _IsStrOrUnicode(import_filename)
+    assert isinstance(import_filename, str)
     super(Import, self).__init__(**kwargs)
     self.attribute_list = attribute_list
     self.import_filename = import_filename
@@ -314,10 +305,10 @@ class Parameter(NodeBase):
   """Represents a method request or response parameter."""
 
   def __init__(self, mojom_name, attribute_list, ordinal, typename, **kwargs):
-    assert _IsStrOrUnicode(mojom_name)
+    assert isinstance(mojom_name, str)
     assert attribute_list is None or isinstance(attribute_list, AttributeList)
     assert ordinal is None or isinstance(ordinal, Ordinal)
-    assert _IsStrOrUnicode(typename)
+    assert isinstance(typename, str)
     super(Parameter, self).__init__(**kwargs)
     self.mojom_name = mojom_name
     self.attribute_list = attribute_list
@@ -363,13 +354,13 @@ class StructField(Definition):
 
   def __init__(self, mojom_name, attribute_list, ordinal, typename,
                default_value, **kwargs):
-    assert _IsStrOrUnicode(mojom_name)
+    assert isinstance(mojom_name, str)
     assert attribute_list is None or isinstance(attribute_list, AttributeList)
     assert ordinal is None or isinstance(ordinal, Ordinal)
-    assert _IsStrOrUnicode(typename)
+    assert isinstance(typename, str)
     # The optional default value is currently either a value as a string or a
     # "wrapped identifier".
-    assert default_value is None or _IsStrOrUnicode(default_value) or \
+    assert default_value is None or isinstance(default_value, str) or \
         isinstance(default_value, tuple)
     super(StructField, self).__init__(mojom_name, **kwargs)
     self.attribute_list = attribute_list
@@ -416,10 +407,10 @@ class Union(Definition):
 
 class UnionField(Definition):
   def __init__(self, mojom_name, attribute_list, ordinal, typename, **kwargs):
-    assert _IsStrOrUnicode(mojom_name)
+    assert isinstance(mojom_name, str)
     assert attribute_list is None or isinstance(attribute_list, AttributeList)
     assert ordinal is None or isinstance(ordinal, Ordinal)
-    assert _IsStrOrUnicode(typename)
+    assert isinstance(typename, str)
     super(UnionField, self).__init__(mojom_name, **kwargs)
     self.attribute_list = attribute_list
     self.ordinal = ordinal

mojo/public/tools/mojom/mojom_parser.py

@@ -30,16 +30,12 @@ from mojom.parse import conditional_features
 
 
 # Disable this for easier debugging.
-# In Python 2, subprocesses just hang when exceptions are thrown :(.
-_ENABLE_MULTIPROCESSING = sys.version_info[0] > 2
+_ENABLE_MULTIPROCESSING = True
 
-if sys.version_info < (3, 4):
-  _MULTIPROCESSING_USES_FORK = sys.platform.startswith('linux')
-else:
-  # https://docs.python.org/3/library/multiprocessing.html#:~:text=bpo-33725
-  if __name__ == '__main__' and sys.platform == 'darwin':
-    multiprocessing.set_start_method('fork')
-  _MULTIPROCESSING_USES_FORK = multiprocessing.get_start_method() == 'fork'
+# https://docs.python.org/3/library/multiprocessing.html#:~:text=bpo-33725
+if __name__ == '__main__' and sys.platform == 'darwin':
+  multiprocessing.set_start_method('fork')
+_MULTIPROCESSING_USES_FORK = multiprocessing.get_start_method() == 'fork'
 
 
 def _ResolveRelativeImportPath(path, roots):

mojo/public/tools/run_all_python_unittests.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # Copyright 2020 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.