#!/usr/bin/env python3

import os

import sys

import re

def append(data, key, value):

cur = data.get(key, [])

cur.append(value)

data[key] = cur

def add_blank(data):

append(data, "blanks", data["num"])

def comment(data):

append(data, "comment", data["num"])

def blank_import(data):

'''Remove extra blank lines associated with _ imports'''

num = data['num']

if not 'comment' in data:

return

comments = data["comment"]

del data['comment']

while comments:

num -= 1

prev = comments.pop(-1)

if prev < num:

break

# at this point, num == line of first comment

blanks = data.get("blanks", [])

if len(blanks) < 1:

return

if blanks[-1] == num - 1:

blanks.pop(-1)

def check_imports(data):

# We only tolerate blank lines between first and third party imports, as well as blank (_) imports

s_line = data.get('line', '').lstrip()

import_state = data.get('import_state', TPIMPORTS)

# ignore . imports, but recognize 3rd party imports of the form github.com/user/proj;

# dot imports are stripped of their leading dot.

if s_line.startswith('.'):

s_line = s_line[1:]

if '.' in s_line and import_state == FPIMPORTS:

data["import_state"] = TPIMPORTS

check_blanks(data)

def check_blanks(data):

did_run = data.get('check_blanks', False)

blanks = data.get('blanks', [])

import_state = data.get('import_state', FPIMPORTS)

if import_state == FPIMPORTS or did_run:

return # nothing to do here

# If we're in 3rd party imports, we should only ever have one blank separating 1st and 3rd party imports

# keep the last blank, as it's likely the correct one, as we're in the transition to 3rd party imports here

data['blanks'] = blanks[:-1]

data['check_blanks'] = True

def complete(data):

blanks = data.get('blanks', [])

for n in blanks:

print("%s:%d: Too many blank lines in imports" % (data["file"], n))

PREIMPORT, IMPORTS, POSTIMPORT, EXTRACOMMENT, BLANKIMPORT = range(5)

FPIMPORTS, TPIMPORTS = 1, 3 # We differentiate between first party (FPIMPORTS) and third party (TPIMPORTS) imports

TRANSITIONS = [

(PREIMPORT, 'import (', IMPORTS),

(PREIMPORT, '', PREIMPORT),

(IMPORTS, '\t//', IMPORTS, comment),

(IMPORTS, '\t_ ', IMPORTS, blank_import),

(IMPORTS, '\t', IMPORTS, check_imports),

(IMPORTS, '\n', IMPORTS, add_blank),

(IMPORTS, ')', POSTIMPORT, complete),

(POSTIMPORT, '', POSTIMPORT),

]

def main():

ok = True

for gofile in sys.argv[1:]:

fileok = scan(gofile)

ok = ok and fileok

if not ok:

sys.exit(1)

def scan(gofile):

data = {"file": gofile}

state = PREIMPORT

for num, line in enumerate(open(gofile), start = 1):

data["num"] = num

data["line"] = line

data["state"] = state

data["import_state"] = FPIMPORTS # Start with first party imports

matched = False

for t in TRANSITIONS:

if state == t[0] and line.startswith(t[1]):

matched = True

data["newstate"] = t[2]

state = t[2]

if len(t) == 4:

t[3](data)

break

if not matched:

print("Unmatched state: %s, line %s" % (state, repr(line)))

return len(data.get("blanks", [])) <= 1

if __name__ == '__main__':

main()