Received-SPF: pass (google.com: best guess record for domain of linux-wireless-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Tue, 29 Oct 2019 08:31:22 +0800
From:   Changbin Du <changbin.du@gmail.com>
To:     Jani Nikula <jani.nikula@linux.intel.com>
Cc:     Changbin Du <changbin.du@gmail.com>,
        Jonathan Corbet <corbet@lwn.net>, linux-pci@vger.kernel.org,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, linux-crypto@vger.kernel.org,
        linux-kselftest@vger.kernel.org, linux-wireless@vger.kernel.org,
        linux-fpga@vger.kernel.org, linux-usb@vger.kernel.org,
        dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org,
        Matthew Wilcox <willy@infradead.org>,
        Thomas Zimmermann <tzimmermann@suse.de>
Subject: Re: [PATCH v2] kernel-doc: rename the kernel-doc directive
 'functions' to 'identifiers'
Message-ID: <20191029003120.llve32crfw63ovpw@mail.google.com>
References: <20191020131717.28990-1-changbin.du@gmail.com>
 <20191024121940.1d6a64df@lwn.net>
 <87woctb9cj.fsf@intel.com>
 <20191025144802.uixg2crhw6h7gghq@mail.google.com>
 <87v9s99q9l.fsf@intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <87v9s99q9l.fsf@intel.com>
User-Agent: NeoMutt/20180716
Sender: linux-wireless-owner@vger.kernel.org
Precedence: bulk

On Mon, Oct 28, 2019 at 11:24:22AM +0200, Jani Nikula wrote:
> On Fri, 25 Oct 2019, Changbin Du <changbin.du@gmail.com> wrote:
> > On Fri, Oct 25, 2019 at 09:57:48AM +0300, Jani Nikula wrote:
> >> On Thu, 24 Oct 2019, Jonathan Corbet <corbet@lwn.net> wrote:
> >> > On Sun, 20 Oct 2019 21:17:17 +0800
> >> > Changbin Du <changbin.du@gmail.com> wrote:
> >> >
> >> >> The 'functions' directive is not only for functions, but also works for
> >> >> structs/unions. So the name is misleading. This patch renames it to
> >> >> 'identifiers', which specific the functions/types to be included in
> >> >> documentation. We keep the old name as an alias of the new one before
> >> >> all documentation are updated.
> >> >> 
> >> >> Signed-off-by: Changbin Du <changbin.du@gmail.com>
> >> >
> >> > So I think this is basically OK, but I have one more request...
> >> >
> >> > [...]
> >> >
> >> >> diff --git a/Documentation/sphinx/kerneldoc.py b/Documentation/sphinx/kerneldoc.py
> >> >> index 1159405cb920..0689f9c37f1e 100644
> >> >> --- a/Documentation/sphinx/kerneldoc.py
> >> >> +++ b/Documentation/sphinx/kerneldoc.py
> >> >> @@ -59,9 +59,10 @@ class KernelDocDirective(Directive):
> >> >>      optional_arguments = 4
> >> >>      option_spec = {
> >> >>          'doc': directives.unchanged_required,
> >> >> -        'functions': directives.unchanged,
> >> >>          'export': directives.unchanged,
> >> >>          'internal': directives.unchanged,
> >> >> +        'identifiers': directives.unchanged,
> >> >> +        'functions': directives.unchanged,  # alias of 'identifiers'
> >> >>      }
> >> >>      has_content = False
> >> >>  
> >> >> @@ -71,6 +72,7 @@ class KernelDocDirective(Directive):
> >> >>  
> >> >>          filename = env.config.kerneldoc_srctree + '/' + self.arguments[0]
> >> >>          export_file_patterns = []
> >> >> +        identifiers = None
> >> >>  
> >> >>          # Tell sphinx of the dependency
> >> >>          env.note_dependency(os.path.abspath(filename))
> >> >> @@ -86,19 +88,22 @@ class KernelDocDirective(Directive):
> >> >>              export_file_patterns = str(self.options.get('internal')).split()
> >> >>          elif 'doc' in self.options:
> >> >>              cmd += ['-function', str(self.options.get('doc'))]
> >> >> +        elif 'identifiers' in self.options:
> >> >> +            identifiers = self.options.get('identifiers').split()
> >> >>          elif 'functions' in self.options:
> >> >> -            functions = self.options.get('functions').split()
> >> >> -            if functions:
> >> >> -                for f in functions:
> >> >> -                    cmd += ['-function', f]
> >> >> -            else:
> >> >> -                cmd += ['-no-doc-sections']
> >> >> +            identifiers = self.options.get('functions').split()
> >> >
> >> > Rather than do this, can you just change the elif line to read:
> >> >
> >> >     elif ('identifiers' in self.options) or ('functions' in self.options):
> >> >
> >> > ...then leave the rest of the code intact?  It keeps the logic together,
> >> > and avoids the confusing distinction between identifiers=='' and
> >> > identifiers==None .
> >> 
> >> I think the problem is you still need to distinguish between the two for
> >> the get('functions') part.
> >> 
> >> One option is to rename 'functions' to 'identifiers' in the above block,
> >> and put something like this above the whole if ladder (untested):
> >> 
> >>         # backward compat
> >>         if 'functions' in self.options:
> >>             if 'identifiers' in self.options:
> >>                 kernellog.warn(env.app, "fail")
> > This will miss the content of 'functions' directive if both exist in
> > same doc.
> 
> Did you not notice your patch does the same, except silently, while this
> would produce a warning? Which one is less surprising?
>
yes, my mistake. Mine does the same thing.

> >
> >>             else:
> >>                 self.options.set('identifiers', self.options.get('functions'))
> >> 
> >> BR,
> >> Jani.
> >>
> > After comparing, I still perfer my original code which is simpler. :)
> 
> But is it, really? I agree with Jon about the distinction between None
> and '' being confusing.
>
Here python is different from C. Both empty string and None are False in python.
Note such condition is common in python.

Again, I am ok with both.

> 
> BR,
> Jani.
> 
> 
> 
> >
> >> 
> >> -- 
> >> Jani Nikula, Intel Open Source Graphics Center
> 
> -- 
> Jani Nikula, Intel Open Source Graphics Center

-- 
Cheers,
Changbin Du