On Tue, Sep 22, 2020 at 05:00:27PM -0400, John Snow wrote: > 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 <js...@redhat.com> > --- > scripts/qapi/commands.py | 4 ++-- > scripts/qapi/doc.py | 2 +- > scripts/qapi/events.py | 8 ++++---- > scripts/qapi/expr.py | 4 ++-- > scripts/qapi/gen.py | 4 ++-- > scripts/qapi/introspect.py | 8 ++++---- > scripts/qapi/main.py | 16 ++++++++-------- > scripts/qapi/parser.py | 4 ++-- > scripts/qapi/schema.py | 8 ++++---- > scripts/qapi/types.py | 6 +++--- > scripts/qapi/visit.py | 6 +++--- > 11 files changed, 35 insertions(+), 35 deletions(-) >
Relative imports are a source of heated debates, but when properly used in a self contained module like here, they are very posititive IMO. Reviewed-by: Cleber Rosa <cr...@redhat.com>
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