When invoking setup.py directly, the default behavior for 'install' is
to run the bdist_egg installation hook, which is ... actually deprecated
by setuptools. It doesn't seem to work quite right anymore.

By contrast, 'pip install' will invoke the bdist_wheel hook
instead. This leads to differences in behavior for the two approaches. I
advocate using pip in the documentation in this directory, but the
'setup.py' which has been used for quite a long time in the Python world
may deceptively appear to work at first glance.

Add an error message that will save a bit of time and frustration
that points the user towards using the supported installation
invocation.

Reported-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
---
 python/setup.py | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/python/setup.py b/python/setup.py
index 2014f81b75..c5bc45919a 100755
--- a/python/setup.py
+++ b/python/setup.py
@@ -5,9 +5,26 @@
 """
 
 import setuptools
+from setuptools.command import bdist_egg
+import sys
 import pkg_resources
 
 
+class bdist_egg_guard(bdist_egg.bdist_egg):
+    """
+    Protect against bdist_egg from being executed
+
+    This prevents calling 'setup.py install' directly, as the 'install'
+    CLI option will invoke the deprecated bdist_egg hook. "pip install"
+    calls the more modern bdist_wheel hook, which is what we want.
+    """
+    def run(self):
+        sys.exit(
+            'Installation directly via setup.py is not supported.\n'
+            'Please use `pip install .` instead.'
+        )
+
+
 def main():
     """
     QEMU tooling installer
@@ -16,7 +33,7 @@ def main():
     # https://medium.com/@daveshawley/safely-using-setup-cfg-for-metadata-1babbe54c108
     pkg_resources.require('setuptools>=39.2')
 
-    setuptools.setup()
+    setuptools.setup(cmdclass={'bdist_egg': bdist_egg_guard})
 
 
 if __name__ == '__main__':
-- 
2.34.1

On Mon, Feb 07, 2022 at 04:30:39PM -0500, John Snow wrote:
> When invoking setup.py directly, the default behavior for 'install' is
> to run the bdist_egg installation hook, which is ... actually deprecated
> by setuptools. It doesn't seem to work quite right anymore.
> 
> By contrast, 'pip install' will invoke the bdist_wheel hook
> instead. This leads to differences in behavior for the two approaches. I
> advocate using pip in the documentation in this directory, but the
> 'setup.py' which has been used for quite a long time in the Python world
> may deceptively appear to work at first glance.

+1 for that. Using setup.py directly is no longer a good practice. All
direct invocations of setup.py are deprecated.

> ---
>  python/setup.py | 19 ++++++++++++++++++-
>  1 file changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/python/setup.py b/python/setup.py
> index 2014f81b75..c5bc45919a 100755
> --- a/python/setup.py
> +++ b/python/setup.py
> @@ -5,9 +5,26 @@
>  """
>  
>  import setuptools
> +from setuptools.command import bdist_egg
> +import sys
>  import pkg_resources
>  
>  
> +class bdist_egg_guard(bdist_egg.bdist_egg):
> +    """
> +    Protect against bdist_egg from being executed
> +
> +    This prevents calling 'setup.py install' directly, as the 'install'
> +    CLI option will invoke the deprecated bdist_egg hook. "pip install"
> +    calls the more modern bdist_wheel hook, which is what we want.
> +    """
> +    def run(self):
> +        sys.exit(
> +            'Installation directly via setup.py is not supported.\n'
> +            'Please use `pip install .` instead.'
> +        )
> +
> +
>  def main():
>      """
>      QEMU tooling installer
> @@ -16,7 +33,7 @@ def main():
>      # https://medium.com/@daveshawley/safely-using-setup-cfg-for-metadata-1babbe54c108
>      pkg_resources.require('setuptools>=39.2')
>  
> -    setuptools.setup()
> +    setuptools.setup(cmdclass={'bdist_egg': bdist_egg_guard})
>  
>  

Reviewed-by: Beraldo Leal <bleal@redhat.com>

--
Beraldo

On Wed, Feb 9, 2022 at 7:51 AM Beraldo Leal <bleal@redhat.com> wrote:
>
> On Mon, Feb 07, 2022 at 04:30:39PM -0500, John Snow wrote:
> > When invoking setup.py directly, the default behavior for 'install' is
> > to run the bdist_egg installation hook, which is ... actually deprecated
> > by setuptools. It doesn't seem to work quite right anymore.
> >
> > By contrast, 'pip install' will invoke the bdist_wheel hook
> > instead. This leads to differences in behavior for the two approaches. I
> > advocate using pip in the documentation in this directory, but the
> > 'setup.py' which has been used for quite a long time in the Python world
> > may deceptively appear to work at first glance.
>
> +1 for that. Using setup.py directly is no longer a good practice. All
> direct invocations of setup.py are deprecated.
>
> > ---
> >  python/setup.py | 19 ++++++++++++++++++-
> >  1 file changed, 18 insertions(+), 1 deletion(-)
> >
> > diff --git a/python/setup.py b/python/setup.py
> > index 2014f81b75..c5bc45919a 100755
> > --- a/python/setup.py
> > +++ b/python/setup.py
> > @@ -5,9 +5,26 @@
> >  """
> >
> >  import setuptools
> > +from setuptools.command import bdist_egg
> > +import sys
> >  import pkg_resources
> >
> >
> > +class bdist_egg_guard(bdist_egg.bdist_egg):
> > +    """
> > +    Protect against bdist_egg from being executed
> > +
> > +    This prevents calling 'setup.py install' directly, as the 'install'
> > +    CLI option will invoke the deprecated bdist_egg hook. "pip install"
> > +    calls the more modern bdist_wheel hook, which is what we want.
> > +    """
> > +    def run(self):
> > +        sys.exit(
> > +            'Installation directly via setup.py is not supported.\n'
> > +            'Please use `pip install .` instead.'
> > +        )
> > +
> > +
> >  def main():
> >      """
> >      QEMU tooling installer
> > @@ -16,7 +33,7 @@ def main():
> >      # https://medium.com/@daveshawley/safely-using-setup-cfg-for-metadata-1babbe54c108
> >      pkg_resources.require('setuptools>=39.2')
> >
> > -    setuptools.setup()
> > +    setuptools.setup(cmdclass={'bdist_egg': bdist_egg_guard})
> >
> >
>
> Reviewed-by: Beraldo Leal <bleal@redhat.com>
>
> --
> Beraldo
>

Thanks, staging this one to my python branch.

--js

On Mon, 7 Feb 2022 at 21:34, John Snow <jsnow@redhat.com> wrote:
>
> When invoking setup.py directly, the default behavior for 'install' is
> to run the bdist_egg installation hook, which is ... actually deprecated
> by setuptools. It doesn't seem to work quite right anymore.
>
> By contrast, 'pip install' will invoke the bdist_wheel hook
> instead. This leads to differences in behavior for the two approaches. I
> advocate using pip in the documentation in this directory, but the
> 'setup.py' which has been used for quite a long time in the Python world
> may deceptively appear to work at first glance.
>
> Add an error message that will save a bit of time and frustration
> that points the user towards using the supported installation
> invocation.

While we're on the topic of python installation, is there any way
to suppress or otherwise deal with the warning Meson prints out?

WARNING: Broken python installation detected. Python files installed
by Meson might not be found by python interpreter.

(I vaguely recall tracking down a meson bug, and this seems to be
some issue the meson developers have with the way Ubuntu/Debian
have done their python packaging. But I forget the details.)

thanks
-- PMM

On Wed, Feb 9, 2022, 8:35 AM Peter Maydell <peter.maydell@linaro.org> wrote:

> On Mon, 7 Feb 2022 at 21:34, John Snow <jsnow@redhat.com> wrote:
> >
> > When invoking setup.py directly, the default behavior for 'install' is
> > to run the bdist_egg installation hook, which is ... actually deprecated
> > by setuptools. It doesn't seem to work quite right anymore.
> >
> > By contrast, 'pip install' will invoke the bdist_wheel hook
> > instead. This leads to differences in behavior for the two approaches. I
> > advocate using pip in the documentation in this directory, but the
> > 'setup.py' which has been used for quite a long time in the Python world
> > may deceptively appear to work at first glance.
> >
> > Add an error message that will save a bit of time and frustration
> > that points the user towards using the supported installation
> > invocation.
>
> While we're on the topic of python installation, is there any way
> to suppress or otherwise deal with the warning Meson prints out?
>
> WARNING: Broken python installation detected. Python files installed
> by Meson might not be found by python interpreter.
>
> (I vaguely recall tracking down a meson bug, and this seems to be
> some issue the meson developers have with the way Ubuntu/Debian
> have done their python packaging. But I forget the details.)
>
> thanks
> -- PMM
>

Unknown, I don't think I see this message on Fedora. Are you seeing it from
Debian? I'll see if it shows up in any of the VM build tests.

>

On Wed, 9 Feb 2022 at 16:54, John Snow <jsnow@redhat.com> wrote:
> On Wed, Feb 9, 2022, 8:35 AM Peter Maydell <peter.maydell@linaro.org> wrote:
>> While we're on the topic of python installation, is there any way
>> to suppress or otherwise deal with the warning Meson prints out?
>>
>> WARNING: Broken python installation detected. Python files installed
>> by Meson might not be found by python interpreter.
>>
>> (I vaguely recall tracking down a meson bug, and this seems to be
>> some issue the meson developers have with the way Ubuntu/Debian
>> have done their python packaging. But I forget the details.)

> Unknown, I don't think I see this message on Fedora. Are you seeing
> it from Debian? I'll see if it shows up in any of the VM build tests.

Yeah, it's an Ubuntu/Debian thing.

-- PMM