python: add demo checker tool using frr.xref

More of a demo on what to do with the frr.xref file, but also slightly
useful in finding vtysh SNAFUs :)

Signed-off-by: David Lamparter <equinox@diac24.net>

python/vtysh-cmd-check.py

@@ -0,0 +1,72 @@
+#!/usr/bin/env python3
+#
+# Quick demo program that checks whether files define commands that aren't
+# in vtysh.  Execute after building.
+#
+# This is free and unencumbered software released into the public domain.
+#
+# Anyone is free to copy, modify, publish, use, compile, sell, or
+# distribute this software, either in source code form or as a compiled
+# binary, for any purpose, commercial or non-commercial, and by any
+# means.
+#
+# In jurisdictions that recognize copyright laws, the author or authors
+# of this software dedicate any and all copyright interest in the
+# software to the public domain. We make this dedication for the benefit
+# of the public at large and to the detriment of our heirs and
+# successors. We intend this dedication to be an overt act of
+# relinquishment in perpetuity of all present and future rights to this
+# software under copyright law.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+# IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+# OTHER DEALINGS IN THE SOFTWARE.
+#
+# For more information, please refer to <http://unlicense.org/>
+
+import os
+import json
+import subprocess
+
+os.chdir(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+with open("frr.xref", "r") as fd:
+    data = json.load(fd)
+
+vtysh_scan, _ = subprocess.Popen(
+    ["make", "var-vtysh_scan"], stdout=subprocess.PIPE
+).communicate()
+vtysh_scan = set(vtysh_scan.decode("US-ASCII").split())
+
+check = set()
+vtysh = {}
+
+for cmd, defs in data["cli"].items():
+    for binary, clidef in defs.items():
+        if clidef["defun"]["file"].startswith("vtysh/"):
+            vtysh[clidef["string"]] = clidef
+
+for cmd, defs in data["cli"].items():
+    for binary, clidef in defs.items():
+        if clidef["defun"]["file"].startswith("vtysh/"):
+            continue
+
+        if clidef["defun"]["file"] not in vtysh_scan:
+            vtysh_def = vtysh.get(clidef["string"])
+            if vtysh_def is not None:
+                print(
+                    "\033[33m%s defines %s, has a custom define in vtysh %s\033[m"
+                    % (clidef["defun"]["file"], cmd, vtysh_def["defun"]["file"])
+                )
+            else:
+                print(
+                    "\033[31m%s defines %s, not in vtysh_scan\033[m"
+                    % (clidef["defun"]["file"], cmd)
+                )
+                check.add(clidef["defun"]["file"])
+
+print("\nfiles to check:\n\t" + " ".join(sorted(check)))