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Benjamin Peterson90f5ba52010-03-11 22:53:45 +00001#! /usr/bin/env python3
Guido van Rossum9ab75cb1998-03-31 14:31:39 +00002
Raymond Hettingerd1fa3db2002-05-15 02:56:03 +00003"""The Tab Nanny despises ambiguous indentation. She knows no mercy.
4
Tim Peters8ac14952002-05-23 15:15:30 +00005tabnanny -- Detection of ambiguous indentation
Raymond Hettingerd1fa3db2002-05-15 02:56:03 +00006
7For the time being this module is intended to be called as a script.
8However it is possible to import it into an IDE and use the function
Tim Peters8ac14952002-05-23 15:15:30 +00009check() described below.
Raymond Hettingerd1fa3db2002-05-15 02:56:03 +000010
11Warning: The API provided by this module is likely to change in future
Tim Peters8ac14952002-05-23 15:15:30 +000012releases; such changes may not be backward compatible.
Raymond Hettingerd1fa3db2002-05-15 02:56:03 +000013"""
Guido van Rossum9ab75cb1998-03-31 14:31:39 +000014
Guido van Rossumaa2a7a41998-06-09 19:02:21 +000015# Released to the public domain, by Tim Peters, 15 April 1998.
Guido van Rossum9ab75cb1998-03-31 14:31:39 +000016
Guido van Rossumdc688332000-02-23 15:32:19 +000017# XXX Note: this is now a standard library module.
18# XXX The API needs to undergo changes however; the current code is too
19# XXX script-like. This will be addressed later.
20
Guido van Rossuma74c5561999-07-30 17:48:20 +000021__version__ = "6"
Guido van Rossum9ab75cb1998-03-31 14:31:39 +000022
23import os
24import sys
25import getopt
26import tokenize
Tim Peters4efb6e92001-06-29 23:51:08 +000027if not hasattr(tokenize, 'NL'):
28 raise ValueError("tokenize.NL doesn't exist -- tokenize module too old")
Guido van Rossum9ab75cb1998-03-31 14:31:39 +000029
Guido van Rossumc5943b12001-08-07 17:19:25 +000030__all__ = ["check", "NannyNag", "process_tokens"]
Skip Montanaro40fc1602001-03-01 04:27:19 +000031
Guido van Rossum9ab75cb1998-03-31 14:31:39 +000032verbose = 0
Andrew M. Kuchlingdc86a4e1998-12-18 13:56:58 +000033filename_only = 0
Guido van Rossum9ab75cb1998-03-31 14:31:39 +000034
Guido van Rossumf9a6d7d1998-09-14 16:22:21 +000035def errprint(*args):
36 sep = ""
37 for arg in args:
38 sys.stderr.write(sep + str(arg))
39 sep = " "
40 sys.stderr.write("\n")
41
Guido van Rossum9ab75cb1998-03-31 14:31:39 +000042def main():
Andrew M. Kuchlingdc86a4e1998-12-18 13:56:58 +000043 global verbose, filename_only
Guido van Rossum9ab75cb1998-03-31 14:31:39 +000044 try:
Andrew M. Kuchlingdc86a4e1998-12-18 13:56:58 +000045 opts, args = getopt.getopt(sys.argv[1:], "qv")
Guido van Rossumb940e112007-01-10 16:19:56 +000046 except getopt.error as msg:
Guido van Rossumf9a6d7d1998-09-14 16:22:21 +000047 errprint(msg)
Guido van Rossum8053d891998-04-06 14:45:26 +000048 return
Guido van Rossum9ab75cb1998-03-31 14:31:39 +000049 for o, a in opts:
Andrew M. Kuchlingdc86a4e1998-12-18 13:56:58 +000050 if o == '-q':
51 filename_only = filename_only + 1
Guido van Rossum9ab75cb1998-03-31 14:31:39 +000052 if o == '-v':
53 verbose = verbose + 1
Guido van Rossum8053d891998-04-06 14:45:26 +000054 if not args:
Guido van Rossumf9a6d7d1998-09-14 16:22:21 +000055 errprint("Usage:", sys.argv[0], "[-v] file_or_directory ...")
Guido van Rossum8053d891998-04-06 14:45:26 +000056 return
Guido van Rossum9ab75cb1998-03-31 14:31:39 +000057 for arg in args:
58 check(arg)
59
Neal Norwitzf74e46c2002-03-31 13:59:18 +000060class NannyNag(Exception):
Raymond Hettingerd1fa3db2002-05-15 02:56:03 +000061 """
62 Raised by tokeneater() if detecting an ambiguous indent.
Tim Peters8ac14952002-05-23 15:15:30 +000063 Captured and handled in check().
Raymond Hettingerd1fa3db2002-05-15 02:56:03 +000064 """
Guido van Rossum9ab75cb1998-03-31 14:31:39 +000065 def __init__(self, lineno, msg, line):
66 self.lineno, self.msg, self.line = lineno, msg, line
67 def get_lineno(self):
68 return self.lineno
69 def get_msg(self):
70 return self.msg
71 def get_line(self):
72 return self.line
73
74def check(file):
Raymond Hettingerd1fa3db2002-05-15 02:56:03 +000075 """check(file_or_dir)
Tim Peters8ac14952002-05-23 15:15:30 +000076
Raymond Hettingerd1fa3db2002-05-15 02:56:03 +000077 If file_or_dir is a directory and not a symbolic link, then recursively
78 descend the directory tree named by file_or_dir, checking all .py files
79 along the way. If file_or_dir is an ordinary Python source file, it is
80 checked for whitespace related problems. The diagnostic messages are
Tim Peters8ac14952002-05-23 15:15:30 +000081 written to standard output using the print statement.
Raymond Hettingerd1fa3db2002-05-15 02:56:03 +000082 """
Tim Peters8ac14952002-05-23 15:15:30 +000083
Guido van Rossum9ab75cb1998-03-31 14:31:39 +000084 if os.path.isdir(file) and not os.path.islink(file):
85 if verbose:
Guido van Rossumbe19ed72007-02-09 05:37:30 +000086 print("%r: listing directory" % (file,))
Guido van Rossum9ab75cb1998-03-31 14:31:39 +000087 names = os.listdir(file)
88 for name in names:
89 fullname = os.path.join(file, name)
90 if (os.path.isdir(fullname) and
91 not os.path.islink(fullname) or
92 os.path.normcase(name[-3:]) == ".py"):
93 check(fullname)
94 return
95
96 try:
Victor Stinner58c07522010-11-09 01:08:59 +000097 f = tokenize.open(file)
Guido van Rossumb940e112007-01-10 16:19:56 +000098 except IOError as msg:
Walter Dörwald70a6b492004-02-12 17:35:32 +000099 errprint("%r: I/O Error: %s" % (file, msg))
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000100 return
101
102 if verbose > 1:
Guido van Rossumbe19ed72007-02-09 05:37:30 +0000103 print("checking %r ..." % file)
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000104
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000105 try:
Tim Peters5ca576e2001-06-18 22:08:13 +0000106 process_tokens(tokenize.generate_tokens(f.readline))
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000107
Guido van Rossumb940e112007-01-10 16:19:56 +0000108 except tokenize.TokenError as msg:
Walter Dörwald70a6b492004-02-12 17:35:32 +0000109 errprint("%r: Token Error: %s" % (file, msg))
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000110 return
111
Guido van Rossumb940e112007-01-10 16:19:56 +0000112 except IndentationError as msg:
Thomas Wouters00ee7ba2006-08-21 19:07:27 +0000113 errprint("%r: Indentation Error: %s" % (file, msg))
114 return
115
Guido van Rossumb940e112007-01-10 16:19:56 +0000116 except NannyNag as nag:
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000117 badline = nag.get_lineno()
118 line = nag.get_line()
119 if verbose:
Guido van Rossumbe19ed72007-02-09 05:37:30 +0000120 print("%r: *** Line %d: trouble in tab city! ***" % (file, badline))
121 print("offending line: %r" % (line,))
122 print(nag.get_msg())
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000123 else:
Guido van Rossuma74c5561999-07-30 17:48:20 +0000124 if ' ' in file: file = '"' + file + '"'
Guido van Rossumbe19ed72007-02-09 05:37:30 +0000125 if filename_only: print(file)
126 else: print(file, badline, repr(line))
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000127 return
128
Ezio Melotti103f17e2012-11-16 13:17:08 +0200129 finally:
130 f.close()
131
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000132 if verbose:
Guido van Rossumbe19ed72007-02-09 05:37:30 +0000133 print("%r: Clean bill of health." % (file,))
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000134
135class Whitespace:
136 # the characters used for space and tab
137 S, T = ' \t'
138
139 # members:
140 # raw
141 # the original string
142 # n
143 # the number of leading whitespace characters in raw
144 # nt
145 # the number of tabs in raw[:n]
146 # norm
147 # the normal form as a pair (count, trailing), where:
148 # count
149 # a tuple such that raw[:n] contains count[i]
150 # instances of S * i + T
151 # trailing
152 # the number of trailing spaces in raw[:n]
153 # It's A Theorem that m.indent_level(t) ==
154 # n.indent_level(t) for all t >= 1 iff m.norm == n.norm.
155 # is_simple
156 # true iff raw[:n] is of the form (T*)(S*)
157
158 def __init__(self, ws):
159 self.raw = ws
160 S, T = Whitespace.S, Whitespace.T
161 count = []
162 b = n = nt = 0
163 for ch in self.raw:
164 if ch == S:
165 n = n + 1
166 b = b + 1
167 elif ch == T:
168 n = n + 1
169 nt = nt + 1
170 if b >= len(count):
171 count = count + [0] * (b - len(count) + 1)
172 count[b] = count[b] + 1
173 b = 0
174 else:
175 break
176 self.n = n
177 self.nt = nt
178 self.norm = tuple(count), b
179 self.is_simple = len(count) <= 1
180
181 # return length of longest contiguous run of spaces (whether or not
182 # preceding a tab)
183 def longest_run_of_spaces(self):
184 count, trailing = self.norm
185 return max(len(count)-1, trailing)
186
187 def indent_level(self, tabsize):
188 # count, il = self.norm
189 # for i in range(len(count)):
190 # if count[i]:
Ezio Melotti103f17e2012-11-16 13:17:08 +0200191 # il = il + (i//tabsize + 1)*tabsize * count[i]
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000192 # return il
193
194 # quicker:
Ezio Melotti103f17e2012-11-16 13:17:08 +0200195 # il = trailing + sum (i//ts + 1)*ts*count[i] =
196 # trailing + ts * sum (i//ts + 1)*count[i] =
197 # trailing + ts * sum i//ts*count[i] + count[i] =
198 # trailing + ts * [(sum i//ts*count[i]) + (sum count[i])] =
199 # trailing + ts * [(sum i//ts*count[i]) + num_tabs]
200 # and note that i//ts*count[i] is 0 when i < ts
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000201
202 count, trailing = self.norm
203 il = 0
204 for i in range(tabsize, len(count)):
Ezio Melotti103f17e2012-11-16 13:17:08 +0200205 il = il + i//tabsize * count[i]
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000206 return trailing + tabsize * (il + self.nt)
207
208 # return true iff self.indent_level(t) == other.indent_level(t)
209 # for all t >= 1
210 def equal(self, other):
211 return self.norm == other.norm
212
213 # return a list of tuples (ts, i1, i2) such that
214 # i1 == self.indent_level(ts) != other.indent_level(ts) == i2.
215 # Intended to be used after not self.equal(other) is known, in which
216 # case it will return at least one witnessing tab size.
217 def not_equal_witness(self, other):
218 n = max(self.longest_run_of_spaces(),
219 other.longest_run_of_spaces()) + 1
220 a = []
221 for ts in range(1, n+1):
222 if self.indent_level(ts) != other.indent_level(ts):
223 a.append( (ts,
224 self.indent_level(ts),
225 other.indent_level(ts)) )
226 return a
227
Tim Petersbc0e9102002-04-04 22:55:58 +0000228 # Return True iff self.indent_level(t) < other.indent_level(t)
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000229 # for all t >= 1.
230 # The algorithm is due to Vincent Broman.
231 # Easy to prove it's correct.
232 # XXXpost that.
233 # Trivial to prove n is sharp (consider T vs ST).
234 # Unknown whether there's a faster general way. I suspected so at
235 # first, but no longer.
236 # For the special (but common!) case where M and N are both of the
237 # form (T*)(S*), M.less(N) iff M.len() < N.len() and
238 # M.num_tabs() <= N.num_tabs(). Proof is easy but kinda long-winded.
239 # XXXwrite that up.
240 # Note that M is of the form (T*)(S*) iff len(M.norm[0]) <= 1.
241 def less(self, other):
242 if self.n >= other.n:
Tim Petersbc0e9102002-04-04 22:55:58 +0000243 return False
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000244 if self.is_simple and other.is_simple:
245 return self.nt <= other.nt
246 n = max(self.longest_run_of_spaces(),
247 other.longest_run_of_spaces()) + 1
248 # the self.n >= other.n test already did it for ts=1
249 for ts in range(2, n+1):
250 if self.indent_level(ts) >= other.indent_level(ts):
Tim Petersbc0e9102002-04-04 22:55:58 +0000251 return False
252 return True
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000253
254 # return a list of tuples (ts, i1, i2) such that
255 # i1 == self.indent_level(ts) >= other.indent_level(ts) == i2.
256 # Intended to be used after not self.less(other) is known, in which
257 # case it will return at least one witnessing tab size.
258 def not_less_witness(self, other):
259 n = max(self.longest_run_of_spaces(),
260 other.longest_run_of_spaces()) + 1
261 a = []
262 for ts in range(1, n+1):
263 if self.indent_level(ts) >= other.indent_level(ts):
264 a.append( (ts,
265 self.indent_level(ts),
266 other.indent_level(ts)) )
267 return a
268
269def format_witnesses(w):
Georg Brandlcbd2ab12010-12-04 10:39:14 +0000270 firsts = (str(tup[0]) for tup in w)
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000271 prefix = "at tab size"
272 if len(w) > 1:
273 prefix = prefix + "s"
Neal Norwitz7ce734c2002-05-31 14:13:04 +0000274 return prefix + " " + ', '.join(firsts)
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000275
Tim Peters4efb6e92001-06-29 23:51:08 +0000276def process_tokens(tokens):
277 INDENT = tokenize.INDENT
278 DEDENT = tokenize.DEDENT
279 NEWLINE = tokenize.NEWLINE
280 JUNK = tokenize.COMMENT, tokenize.NL
Tim Peters5ca576e2001-06-18 22:08:13 +0000281 indents = [Whitespace("")]
282 check_equal = 0
283
284 for (type, token, start, end, line) in tokens:
Tim Petersb90f89a2001-01-15 03:26:36 +0000285 if type == NEWLINE:
286 # a program statement, or ENDMARKER, will eventually follow,
287 # after some (possibly empty) run of tokens of the form
288 # (NL | COMMENT)* (INDENT | DEDENT+)?
289 # If an INDENT appears, setting check_equal is wrong, and will
290 # be undone when we see the INDENT.
291 check_equal = 1
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000292
Tim Petersb90f89a2001-01-15 03:26:36 +0000293 elif type == INDENT:
294 check_equal = 0
295 thisguy = Whitespace(token)
296 if not indents[-1].less(thisguy):
297 witness = indents[-1].not_less_witness(thisguy)
298 msg = "indent not greater e.g. " + format_witnesses(witness)
299 raise NannyNag(start[0], msg, line)
300 indents.append(thisguy)
Guido van Rossumf4b44fa1998-04-06 14:41:20 +0000301
Tim Petersb90f89a2001-01-15 03:26:36 +0000302 elif type == DEDENT:
303 # there's nothing we need to check here! what's important is
304 # that when the run of DEDENTs ends, the indentation of the
305 # program statement (or ENDMARKER) that triggered the run is
306 # equal to what's left at the top of the indents stack
Guido van Rossumaa2a7a41998-06-09 19:02:21 +0000307
Tim Petersb90f89a2001-01-15 03:26:36 +0000308 # Ouch! This assert triggers if the last line of the source
309 # is indented *and* lacks a newline -- then DEDENTs pop out
310 # of thin air.
311 # assert check_equal # else no earlier NEWLINE, or an earlier INDENT
312 check_equal = 1
Guido van Rossumaa2a7a41998-06-09 19:02:21 +0000313
Tim Petersb90f89a2001-01-15 03:26:36 +0000314 del indents[-1]
Guido van Rossumf4b44fa1998-04-06 14:41:20 +0000315
Tim Petersb90f89a2001-01-15 03:26:36 +0000316 elif check_equal and type not in JUNK:
317 # this is the first "real token" following a NEWLINE, so it
318 # must be the first token of the next program statement, or an
319 # ENDMARKER; the "line" argument exposes the leading whitespace
320 # for this statement; in the case of ENDMARKER, line is an empty
321 # string, so will properly match the empty string with which the
322 # "indents" stack was seeded
323 check_equal = 0
324 thisguy = Whitespace(line)
325 if not indents[-1].equal(thisguy):
326 witness = indents[-1].not_equal_witness(thisguy)
327 msg = "indent not equal e.g. " + format_witnesses(witness)
328 raise NannyNag(start[0], msg, line)
Guido van Rossumf4b44fa1998-04-06 14:41:20 +0000329
Guido van Rossum9ab75cb1998-03-31 14:31:39 +0000330
331if __name__ == '__main__':
332 main()