tools/checkpython: Checking - and formatting - python code

Uses yapf [https://github.com/google/yapf] to format code. Currently,
is invoked as a subprocess, but being a Python module itself, that could
be changed in future.

A helper script gathers modified '.py' files and feeds them to yapf.
One can use git range format, such as HEAD~3, to define which patches
will have its Python files inspected, but the whole file is reformatted,
not only what was changed: that could be improved, as yapf accepts a
line range of file to format, but that sounded too much effort for now.

Current Python files were reformatted. Manual intervention was done to
tweak long strings: breaking them manually and applying format looked
better than:

  print(
      "Really long string"
      )

README.md

@@ -58,8 +58,8 @@ connection there will also receive routed packets.
 ### Contributing ###
 
 Pull-requests are accepted on GitHub. Make sure to check coding style with the
-provided script in tools/checkpatch, check for memory leaks with valgrind and
-test on real hardware.
+provided script in tools/checkpatch and tools/checkpython, check for memory leaks
+with valgrind and test on real hardware.
 
 ### Samples ###
 

examples/arm.py

@@ -24,7 +24,5 @@
 mav = mavutil.mavlink_connection('udpin:' + sys.argv[1])
 mav.wait_heartbeat()
 mav.mav.command_long_send(mav.target_system, mav.target_component,
-                          mavutil.mavlink.MAV_CMD_COMPONENT_ARM_DISARM,
-                          0,
-                          1,
+                          mavutil.mavlink.MAV_CMD_COMPONENT_ARM_DISARM, 0, 1,
                           0, 0, 0, 0, 0, 0)

examples/receiver.py

@@ -25,13 +25,15 @@
 
 if len(sys.argv) != 3:
     print("Usage: %s <ip:udp_port> <system-id>" % (sys.argv[0]))
-    print("Receive mavlink heartbeats on specified interface. Respond with a ping message")
+    print("Receive mavlink heartbeats on specified interface. "
+          "Respond with a ping message")
     quit()
 
 srcSystem = int(sys.argv[2])
-mav = mavutil.mavlink_connection('udpin:' + sys.argv[1], source_system = srcSystem)
+mav = mavutil.mavlink_connection(
+    'udpin:' + sys.argv[1], source_system=srcSystem)
 
-while(True):
+while (True):
     msg = mav.recv_match(blocking=True)
     print("Message from %d: %s" % (msg.get_srcSystem(), msg))
     if msg.target_system == 0:
@@ -40,5 +42,6 @@
         print("\tMessage sent to me")
     else:
         print("\tMessage sent to other")
-    mav.mav.ping_send(int(time.time() * 1000), msg.seq, msg.get_srcSystem(), msg.get_srcComponent())
-
+    mav.mav.ping_send(
+        int(time.time() * 1000), msg.seq,
+        msg.get_srcSystem(), msg.get_srcComponent())

examples/sender.py

@@ -26,23 +26,29 @@
 import time
 
 if len(sys.argv) != 4:
-    print("Usage: %s <ip:udp_port> <system-id> <target-system-id>" % (sys.argv[0]))
-    print("Send mavlink pings, using given <system-id> and <target-system-id>, to specified interface")
+    print("Usage: %s <ip:udp_port> <system-id> <target-system-id>" %
+          (sys.argv[0]))
+    print(
+        "Send mavlink pings, using given <system-id> and <target-system-id>, "
+        "to specified interface")
     quit()
 
-mav = mavutil.mavlink_connection('udpout:' + sys.argv[1], source_system = int(sys.argv[2]))
+mav = mavutil.mavlink_connection(
+    'udpout:' + sys.argv[1], source_system=int(sys.argv[2]))
+
 
 def pingloop():
     i = 0
-    while(True):
-        mav.mav.ping_send(int(time.time() * 1000), i, int(sys.argv[3]), 0)
+    while (True):
+        mav.mav.ping_send(int(time.time() * 1000), i, int(sys.argv[3]), 1)
         i = i + 1
         sleep(1)
 
+
 pingthread = Thread(target=pingloop)
 pingthread.daemon = True
 pingthread.start()
 
-while(True):
+while (True):
     msg = mav.recv_match(blocking=True)
     print("Message from %d: %s" % (msg.get_srcSystem(), msg))

tools/checkpython

@@ -0,0 +1,35 @@
+#!/usr/bin/env python
+
+from __future__ import print_function
+
+import subprocess
+import sys
+
+
+def run_command(cmd):
+    try:
+        output = subprocess.check_output(
+            cmd, stderr=subprocess.STDOUT, shell=True, universal_newlines=True)
+        return output
+
+    except subprocess.CalledProcessError as e:
+        print("Could not run command `%s`: %s" % (cmd, e.output))
+        return None
+
+
+revision = ""
+if len(sys.argv) == 2:
+    revision = sys.argv[1]
+if len(sys.argv) > 2:
+    print("Usage: %s [revision]")
+    quit()
+
+cmd = "git diff --diff-filter=ACMR --oneline --name-only %s  -- '*.py'" % revision
+file_list = run_command(cmd)
+
+if len(file_list) == 0:
+    print("No changes on current working dir and no revision specified. Nothing to do")
+else:
+    # TODO Maybe use as a module, so we can output which files were changed?
+    cmd = "yapf -i %s" % (file_list.replace("\n", " "))
+    run_command(cmd)