1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
|
'''
Given two similar files, for example one with an additional optimization pass,
and with different results, will bisect between them to find the smallest
diff that makes the outputs different.
'''
import os, sys, shutil
from subprocess import Popen, PIPE, STDOUT
__rootpath__ = os.path.abspath(os.path.dirname(os.path.dirname(__file__)))
def path_from_root(*pathelems):
return os.path.join(__rootpath__, *pathelems)
exec(open(path_from_root('tools', 'shared.py'), 'r').read())
file1 = open(sys.argv[1]).read()
file2 = open(sys.argv[2]).read()
leftf = open('left', 'w')
leftf.write(file1)
leftf.close()
rightf = open('right', 'w')
rightf.write(file2)
rightf.close()
print 'running files'
left_result = run_js('left', stderr=PIPE)
right_result = run_js('right', stderr=PIPE) # right as in left-right, not as in correct
assert left_result != right_result
# Calculate diff chunks
print 'diffing'
diff = Popen(['diff', '-U', '5', 'left', 'right'], stdout=PIPE).communicate()[0].split('\n')
pre_diff = diff[:2]
diff = diff[2:]
chunks = []
curr = []
for i in range(len(diff)):
if diff[i].startswith('@'):
if len(curr) > 0:
chunks.append(curr)
curr = [diff[i]]
else:
curr.append(diff[i])
if len(curr) > 0:
chunks.append(curr)
# Bisect both sides of the span, until we have a single chunk
low = 0
high = len(chunks)
print 'beginning bisection, %d chunks' % high
while high-low > 2:
mid = (low + high)/2
print ' current status: %d - %d - %d' % (low, mid, high)
# Take chunks from the middle and on. This is important because the eliminator removes variables, so starting from the beginning will add errors
curr_diff = '\n'.join(map(lambda parts: '\n'.join(parts), chunks[mid:])) + '\n'
difff = open('diff.diff', 'w')
difff.write(curr_diff)
difff.close()
shutil.copy('left', 'middle')
Popen(['patch', 'middle', 'diff.diff'], stdout=PIPE, stderr=PIPE).communicate()
result = run_js('middle', stderr=PIPE)
if result == left_result:
high = mid+1
else:
low = mid
critical = '\n'.join(chunks[low]) + '\n'
c = open('critical.diff', 'w')
c.write(critical)
c.close()
print 'sanity check'
shutil.copy('middle', 'middle2')
Popen(['patch', 'middle2', 'critical.diff'], stdout=PIPE, stderr=PIPE).communicate()
assert run_js('middle', stderr=PIPE) == left_result
assert run_js('middle2', stderr=PIPE) != left_result
print 'middle is like left, middle2 is like right, critical.diff is the difference that matters,'
print critical
|
