/
empty_checks_spec.rb
135 lines (118 loc) · 6.73 KB
/
empty_checks_spec.rb
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
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
require_relative '../../spec_helper'
require_relative '../fixtures/classes'
describe "empty checks in Regexps" do
it "allow extra empty iterations" do
/()?/.match("").to_a.should == ["", ""]
/(a*)?/.match("").to_a.should == ["", ""]
/(a*)*/.match("").to_a.should == ["", ""]
# The bounds are high to avoid DFA-based matchers in implementations
# and to check backtracking behavior.
/(?:a|()){500,1000}/.match("a" * 500).to_a.should == ["a" * 500, ""]
# Variations with non-greedy loops.
/()??/.match("").to_a.should == ["", nil]
/(a*?)?/.match("").to_a.should == ["", ""]
/(a*)??/.match("").to_a.should == ["", nil]
/(a*?)??/.match("").to_a.should == ["", nil]
/(a*?)*/.match("").to_a.should == ["", ""]
/(a*)*?/.match("").to_a.should == ["", nil]
/(a*?)*?/.match("").to_a.should == ["", nil]
end
it "allow empty iterations in the middle of a loop" do
# One empty iteration between a's and b's.
/(a|\2b|())*/.match("aaabbb").to_a.should == ["aaabbb", "", ""]
/(a|\2b|()){2,4}/.match("aaabbb").to_a.should == ["aaa", "", ""]
# Two empty iterations between a's and b's.
/(a|\2b|\3()|())*/.match("aaabbb").to_a.should == ["aaabbb", "", "", ""]
/(a|\2b|\3()|()){2,4}/.match("aaabbb").to_a.should == ["aaa", "", nil, ""]
# Check that the empty iteration correctly updates the loop counter.
/(a|\2b|()){20,24}/.match("a" * 20 + "b" * 5).to_a.should == ["a" * 20 + "b" * 3, "b", ""]
# Variations with non-greedy loops.
/(a|\2b|())*?/.match("aaabbb").to_a.should == ["", nil, nil]
/(a|\2b|()){2,4}/.match("aaabbb").to_a.should == ["aaa", "", ""]
/(a|\2b|\3()|())*?/.match("aaabbb").to_a.should == ["", nil, nil, nil]
/(a|\2b|\3()|()){2,4}/.match("aaabbb").to_a.should == ["aaa", "", nil, ""]
/(a|\2b|()){20,24}/.match("a" * 20 + "b" * 5).to_a.should == ["a" * 20 + "b" * 3, "b", ""]
end
it "make the Regexp proceed past the quantified expression on failure" do
# If the contents of the ()* quantified group are empty (i.e., they fail
# the empty check), the loop will abort. It will not try to backtrack
# and try other alternatives (e.g. matching the "a") like in other Regexp
# dialects such as ECMAScript.
/(?:|a)*/.match("aaa").to_a.should == [""]
/(?:()|a)*/.match("aaa").to_a.should == ["", ""]
/(|a)*/.match("aaa").to_a.should == ["", ""]
/(()|a)*/.match("aaa").to_a.should == ["", "", ""]
# Same expressions, but with backreferences, to force the use of non-DFA-based
# engines.
/()\1(?:|a)*/.match("aaa").to_a.should == ["", ""]
/()\1(?:()|a)*/.match("aaa").to_a.should == ["", "", ""]
/()\1(|a)*/.match("aaa").to_a.should == ["", "", ""]
/()\1(()|a)*/.match("aaa").to_a.should == ["", "", "", ""]
# Variations with other zero-width contents of the quantified
# group: backreferences, capture groups, lookarounds
/()(?:\1|a)*/.match("aaa").to_a.should == ["", ""]
/()(?:()\1|a)*/.match("aaa").to_a.should == ["", "", ""]
/()(?:(\1)|a)*/.match("aaa").to_a.should == ["", "", ""]
/()(?:\1()|a)*/.match("aaa").to_a.should == ["", "", ""]
/()(\1|a)*/.match("aaa").to_a.should == ["", "", ""]
/()(()\1|a)*/.match("aaa").to_a.should == ["", "", "", ""]
/()((\1)|a)*/.match("aaa").to_a.should == ["", "", "", ""]
/()(\1()|a)*/.match("aaa").to_a.should == ["", "", "", ""]
/(?:(?=a)|a)*/.match("aaa").to_a.should == [""]
/(?:(?=a)()|a)*/.match("aaa").to_a.should == ["", ""]
/(?:()(?=a)|a)*/.match("aaa").to_a.should == ["", ""]
/(?:((?=a))|a)*/.match("aaa").to_a.should == ["", ""]
/()\1(?:(?=a)|a)*/.match("aaa").to_a.should == ["", ""]
/()\1(?:(?=a)()|a)*/.match("aaa").to_a.should == ["", "", ""]
/()\1(?:()(?=a)|a)*/.match("aaa").to_a.should == ["", "", ""]
/()\1(?:((?=a))|a)*/.match("aaa").to_a.should == ["", "", ""]
# Variations with non-greedy loops.
/(?:|a)*?/.match("aaa").to_a.should == [""]
/(?:()|a)*?/.match("aaa").to_a.should == ["", nil]
/(|a)*?/.match("aaa").to_a.should == ["", nil]
/(()|a)*?/.match("aaa").to_a.should == ["", nil, nil]
/()\1(?:|a)*?/.match("aaa").to_a.should == ["", ""]
/()\1(?:()|a)*?/.match("aaa").to_a.should == ["", "", nil]
/()\1(|a)*?/.match("aaa").to_a.should == ["", "", nil]
/()\1(()|a)*?/.match("aaa").to_a.should == ["", "", nil, nil]
/()(?:\1|a)*?/.match("aaa").to_a.should == ["", ""]
/()(?:()\1|a)*?/.match("aaa").to_a.should == ["", "", nil]
/()(?:(\1)|a)*?/.match("aaa").to_a.should == ["", "", nil]
/()(?:\1()|a)*?/.match("aaa").to_a.should == ["", "", nil]
/()(\1|a)*?/.match("aaa").to_a.should == ["", "", nil]
/()(()\1|a)*?/.match("aaa").to_a.should == ["", "", nil, nil]
/()((\1)|a)*?/.match("aaa").to_a.should == ["", "", nil, nil]
/()(\1()|a)*?/.match("aaa").to_a.should == ["", "", nil, nil]
/(?:(?=a)|a)*?/.match("aaa").to_a.should == [""]
/(?:(?=a)()|a)*?/.match("aaa").to_a.should == ["", nil]
/(?:()(?=a)|a)*?/.match("aaa").to_a.should == ["", nil]
/(?:((?=a))|a)*?/.match("aaa").to_a.should == ["", nil]
/()\1(?:(?=a)|a)*?/.match("aaa").to_a.should == ["", ""]
/()\1(?:(?=a)()|a)*?/.match("aaa").to_a.should == ["", "", nil]
/()\1(?:()(?=a)|a)*?/.match("aaa").to_a.should == ["", "", nil]
/()\1(?:((?=a))|a)*?/.match("aaa").to_a.should == ["", "", nil]
end
it "shouldn't cause the Regexp parser to get stuck in a loop" do
/(|a|\2b|())*/.match("aaabbb").to_a.should == ["", "", nil]
/(a||\2b|())*/.match("aaabbb").to_a.should == ["aaa", "", nil]
/(a|\2b||())*/.match("aaabbb").to_a.should == ["aaa", "", nil]
/(a|\2b|()|)*/.match("aaabbb").to_a.should == ["aaabbb", "", ""]
/(()|a|\3b|())*/.match("aaabbb").to_a.should == ["", "", "", nil]
/(a|()|\3b|())*/.match("aaabbb").to_a.should == ["aaa", "", "", nil]
/(a|\2b|()|())*/.match("aaabbb").to_a.should == ["aaabbb", "", "", nil]
/(a|\3b|()|())*/.match("aaabbb").to_a.should == ["aaa", "", "", nil]
/(a|()|())*/.match("aaa").to_a.should == ["aaa", "", "", nil]
/^(()|a|())*$/.match("aaa").to_a.should == ["aaa", "", "", nil]
# Variations with non-greedy loops.
/(|a|\2b|())*?/.match("aaabbb").to_a.should == ["", nil, nil]
/(a||\2b|())*?/.match("aaabbb").to_a.should == ["", nil, nil]
/(a|\2b||())*?/.match("aaabbb").to_a.should == ["", nil, nil]
/(a|\2b|()|)*?/.match("aaabbb").to_a.should == ["", nil, nil]
/(()|a|\3b|())*?/.match("aaabbb").to_a.should == ["", nil, nil, nil]
/(a|()|\3b|())*?/.match("aaabbb").to_a.should == ["", nil, nil, nil]
/(a|\2b|()|())*?/.match("aaabbb").to_a.should == ["", nil, nil, nil]
/(a|\3b|()|())*?/.match("aaabbb").to_a.should == ["", nil, nil, nil]
/(a|()|())*?/.match("aaa").to_a.should == ["", nil, nil, nil]
/^(()|a|())*?$/.match("aaa").to_a.should == ["aaa", "a", "", nil]
end
end