haraldwolff/qemu-patch-raspberry4
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qapi: Prefer explicit relative imports

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All of the QAPI include statements are changed to be package-aware, as
explicit relative imports.

A quirk of Python packages is that the name of the package exists only
*outside* of the package. This means that to a module inside of the qapi
folder, there is inherently no such thing as the "qapi" package. The
reason these imports work is because the "qapi" package exists in the
context of the caller -- the execution shim, where sys.path includes a
directory that has a 'qapi' folder in it.

When we write "from qapi import sibling", we are NOT referencing the folder
'qapi', but rather "any package named qapi in sys.path". If you should
so happen to have a 'qapi' package in your path, it will use *that*
package.

When we write "from .sibling import foo", we always reference explicitly
our sibling module; guaranteeing consistency in *where* we are importing
these modules from.

This can be useful when working with virtual environments and packages
in development mode. In development mode, a package is installed as a
series of symlinks that forwards to your same source files. The problem
arises because code quality checkers will follow "import qapi.x" to the
"installed" version instead of the sibling file and -- even though they
are the same file -- they have different module paths, and this causes
cyclic import problems, false positive type mismatch errors, and more.

It can also be useful when dealing with hierarchical packages, e.g. if
we allow qemu.core.qmp, qemu.qapi.parser, etc.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20201009161558.107041-6-jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
This commit is contained in:
John Snow 2020-10-09 12:15:27 -04:00 committed by Markus Armbruster
parent a76ab215ec
commit 7137a96099
10 changed files with 33 additions and 33 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
scripts/qapi/commands.py
View file

@ -13,8 +13,8 @@ This work is licensed under the terms of the GNU GPL, version 2.
See the COPYING file in the top-level directory. See the COPYING file in the top-level directory.
""" """
from qapi.common import * from .common import *
from qapi.gen import QAPIGenCCode, QAPISchemaModularCVisitor, ifcontext from .gen import QAPIGenCCode, QAPISchemaModularCVisitor, ifcontext
def gen_command_decl(name, arg_type, boxed, ret_type): def gen_command_decl(name, arg_type, boxed, ret_type):

8
scripts/qapi/events.py
View file

@ -12,10 +12,10 @@ This work is licensed under the terms of the GNU GPL, version 2.
See the COPYING file in the top-level directory. See the COPYING file in the top-level directory.
""" """
from qapi.common import * from .common import *
from qapi.gen import QAPISchemaModularCVisitor, ifcontext from .gen import QAPISchemaModularCVisitor, ifcontext
from qapi.schema import QAPISchemaEnumMember from .schema import QAPISchemaEnumMember
from qapi.types import gen_enum, gen_enum_lookup from .types import gen_enum, gen_enum_lookup
def build_event_send_proto(name, arg_type, boxed): def build_event_send_proto(name, arg_type, boxed):

4
scripts/qapi/expr.py
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@ -16,8 +16,8 @@
import re import re
from collections import OrderedDict from collections import OrderedDict
from qapi.common import c_name from .common import c_name
from qapi.error import QAPISemError from .error import QAPISemError
# Names must be letters, numbers, -, and _. They must start with letter, # Names must be letters, numbers, -, and _. They must start with letter,

4
scripts/qapi/gen.py
View file

@ -17,8 +17,8 @@ import os
import re import re
from contextlib import contextmanager from contextlib import contextmanager
from qapi.common import * from .common import *
from qapi.schema import QAPISchemaVisitor from .schema import QAPISchemaVisitor
class QAPIGen: class QAPIGen:

8
scripts/qapi/introspect.py
View file

@ -10,10 +10,10 @@ This work is licensed under the terms of the GNU GPL, version 2.
See the COPYING file in the top-level directory. See the COPYING file in the top-level directory.
""" """
from qapi.common import * from .common import *
from qapi.gen import QAPISchemaMonolithicCVisitor from .gen import QAPISchemaMonolithicCVisitor
from qapi.schema import (QAPISchemaArrayType, QAPISchemaBuiltinType, from .schema import (QAPISchemaArrayType, QAPISchemaBuiltinType,
QAPISchemaType) QAPISchemaType)
def _make_tree(obj, ifcond, features, extra=None): def _make_tree(obj, ifcond, features, extra=None):

14
scripts/qapi/main.py
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@ -12,13 +12,13 @@ import re
import sys import sys
from typing import Optional from typing import Optional
from qapi.commands import gen_commands from .commands import gen_commands
from qapi.error import QAPIError from .error import QAPIError
from qapi.events import gen_events from .events import gen_events
from qapi.introspect import gen_introspect from .introspect import gen_introspect
from qapi.schema import QAPISchema from .schema import QAPISchema
from qapi.types import gen_types from .types import gen_types
from qapi.visit import gen_visit from .visit import gen_visit
def invalid_prefix_char(prefix: str) -> Optional[str]: def invalid_prefix_char(prefix: str) -> Optional[str]:

4
scripts/qapi/parser.py
View file

@ -18,8 +18,8 @@ import os
import re import re
from collections import OrderedDict from collections import OrderedDict
from qapi.error import QAPIParseError, QAPISemError from .error import QAPIParseError, QAPISemError
from qapi.source import QAPISourceInfo from .source import QAPISourceInfo
class QAPISchemaParser: class QAPISchemaParser:

8
scripts/qapi/schema.py
View file

@ -18,10 +18,10 @@ import os
import re import re
from collections import OrderedDict from collections import OrderedDict
from qapi.common import c_name, pointer_suffix from .common import c_name, pointer_suffix
from qapi.error import QAPIError, QAPISemError from .error import QAPIError, QAPISemError
from qapi.expr import check_exprs from .expr import check_exprs
from qapi.parser import QAPISchemaParser from .parser import QAPISchemaParser
class QAPISchemaEntity: class QAPISchemaEntity:

6
scripts/qapi/types.py
View file

@ -13,9 +13,9 @@ This work is licensed under the terms of the GNU GPL, version 2.
# See the COPYING file in the top-level directory. # See the COPYING file in the top-level directory.
""" """
from qapi.common import * from .common import *
from qapi.gen import QAPISchemaModularCVisitor, ifcontext from .gen import QAPISchemaModularCVisitor, ifcontext
from qapi.schema import QAPISchemaEnumMember, QAPISchemaObjectType from .schema import QAPISchemaEnumMember, QAPISchemaObjectType
# variants must be emitted before their container; track what has already # variants must be emitted before their container; track what has already

6
scripts/qapi/visit.py
View file

@ -13,9 +13,9 @@ This work is licensed under the terms of the GNU GPL, version 2.
See the COPYING file in the top-level directory. See the COPYING file in the top-level directory.
""" """
from qapi.common import * from .common import *
from qapi.gen import QAPISchemaModularCVisitor, ifcontext from .gen import QAPISchemaModularCVisitor, ifcontext
from qapi.schema import QAPISchemaObjectType from .schema import QAPISchemaObjectType
def gen_visit_decl(name, scalar=False): def gen_visit_decl(name, scalar=False):