docs: kdoc: remove support for an external kernel-doc from sphinx

The ability to build the docs with an external kernel-doc program involves
some truly confusing logic and complicates the task of moving kernel-doc
out of scripts/.  But this feature is not useful for normal documentation
builds, and the external kernel-doc can always be run by hand when it needs
debugging.  So just remove that feature and make life easier.

There is still a bunch of logic to build a command line that we never use;
the idea is to be able to output it, but I'm not sure if that is worth
keeping.

Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <a97a8361546648906344457a7e92e4db533048a9.1768823489.git.mchehab+huawei@kernel.org>

Author: Jonathan Corbet

Documentation/sphinx/kerneldoc.py

@@ -190,35 +190,7 @@ def handle_args(self):
 
         return cmd
 
-    def run_cmd(self, cmd):
-        """
-        Execute an external kernel-doc command.
-        """
-
-        env = self.state.document.settings.env
-        node = nodes.section()
-
-        p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-        out, err = p.communicate()
-
-        out, err = codecs.decode(out, 'utf-8'), codecs.decode(err, 'utf-8')
-
-        if p.returncode != 0:
-            sys.stderr.write(err)
-
-            logger.warning("kernel-doc '%s' failed with return code %d"
-                                % (" ".join(cmd), p.returncode))
-            return [nodes.error(None, nodes.paragraph(text = "kernel-doc missing"))]
-        elif env.config.kerneldoc_verbosity > 0:
-            sys.stderr.write(err)
-
-        filenames = self.parse_args["file_list"]
-        for filename in filenames:
-            self.parse_msg(filename, node, out, cmd)
-
-        return node.children
-
-    def parse_msg(self, filename, node, out, cmd):
+    def parse_msg(self, filename, node, out):
         """
         Handles a kernel-doc output for a given file
         """
@@ -244,7 +216,7 @@ def parse_msg(self, filename, node, out, cmd):
 
         self.do_parse(result, node)
 
-    def run_kdoc(self, cmd, kfiles):
+    def run_kdoc(self, kfiles):
         """
         Execute kernel-doc classes directly instead of running as a separate
         command.
@@ -258,23 +230,17 @@ def run_kdoc(self, cmd, kfiles):
         filenames = self.parse_args["file_list"]
 
         for filename, out in kfiles.msg(**self.msg_args, filenames=filenames):
-            self.parse_msg(filename, node, out, cmd)
+            self.parse_msg(filename, node, out)
 
         return node.children
 
     def run(self):
-        global kfiles
-
         cmd = self.handle_args()
         if self.verbose >= 1:
             logger.info(cmd_str(cmd))
 
         try:
-            if kfiles:
-                return self.run_kdoc(cmd, kfiles)
-            else:
-                return self.run_cmd(cmd)
-
+            return self.run_kdoc(kfiles)
         except Exception as e:  # pylint: disable=W0703
             logger.warning("kernel-doc '%s' processing failed with: %s" %
                            (cmd_str(cmd), pformat(e)))
@@ -286,15 +252,8 @@ def do_parse(self, result, node):
 
 def setup_kfiles(app):
     global kfiles
-
-    kerneldoc_bin = app.env.config.kerneldoc_bin
-
-    if kerneldoc_bin and kerneldoc_bin.endswith("kernel-doc.py"):
-        print("Using Python kernel-doc")
-        out_style = RestFormat()
-        kfiles = KernelFiles(out_style=out_style, logger=logger)
-    else:
-        print(f"Using {kerneldoc_bin}")
+    out_style = RestFormat()
+    kfiles = KernelFiles(out_style=out_style, logger=logger)
 
 
 def setup(app):