1// RUN: %check_clang_tidy %s bugprone-string-constructor %t
2
3namespace std {
4template <typename T>
5class allocator {};
6template <typename T>
7class char_traits {};
8template <typename C, typename T = std::char_traits<C>, typename A = std::allocator<C> >
9struct basic_string {
10 basic_string();
11 basic_string(const C*, unsigned int size);
12 basic_string(const C *, const A &allocator = A());
13 basic_string(unsigned int size, C c);
14 basic_string(const C*, unsigned int pos, unsigned int size);
15};
16typedef basic_string<char> string;
17typedef basic_string<wchar_t> wstring;
18
19template <typename C, typename T = std::char_traits<C>>
20struct basic_string_view {
21 basic_string_view();
22 basic_string_view(const C *, unsigned int size);
23 basic_string_view(const C *);
24};
25typedef basic_string_view<char> string_view;
26typedef basic_string_view<wchar_t> wstring_view;
27}
28
29const char* kText = "";
30const char kText2[] = "";
31extern const char kText3[];
32
33void Test() {
34 std::string str('x', 4);
35 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: string constructor parameters are probably swapped; expecting string(count, character) [bugprone-string-constructor]
36 // CHECK-FIXES: std::string str(4, 'x');
37 std::wstring wstr(L'x', 4);
38 // CHECK-MESSAGES: [[@LINE-1]]:16: warning: string constructor parameters are probably swapped
39 // CHECK-FIXES: std::wstring wstr(4, L'x');
40 std::string s0(0, 'x');
41 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: constructor creating an empty string
42 std::string s1(-4, 'x');
43 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: negative value used as length parameter
44 std::string s2(0x1000000, 'x');
45 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: suspicious large length parameter
46
47 std::string q0("test", 0);
48 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: constructor creating an empty string
49 std::string q1(kText, -4);
50 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: negative value used as length parameter
51 std::string q2("test", 200);
52 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: length is bigger than string literal size
53 std::string t1("test", 5);
54 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: length is bigger than string literal size
55 std::string q3(kText, 200);
56 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: length is bigger than string literal size
57 std::string q4(kText2, 200);
58 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: length is bigger than string literal size
59 std::string q5(kText3, 0x1000000);
60 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: suspicious large length parameter
61 std::string q6(nullptr);
62 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: constructing string from nullptr is undefined behaviour
63 std::string q7 = 0;
64 // CHECK-MESSAGES: [[@LINE-1]]:20: warning: constructing string from nullptr is undefined behaviour
65
66 std::string r1("test", 1, 0);
67 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: constructor creating an empty string
68 std::string r2("test", 0, -4);
69 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: negative value used as length parameter
70 std::string r3("test", -4, 1);
71 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: negative value used as position of the first character parameter
72 std::string r4("test", 0, 0x1000000);
73 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: suspicious large length parameter
74 std::string r5("test", 0, 5);
75 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: length is bigger than string literal size
76 std::string r6("test", 3, 2);
77 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: length is bigger than remaining string literal size
78 std::string r7("test", 4, 1);
79 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: position of the first character parameter is bigger than string literal character range
80}
81
82void TestView() {
83 std::string_view q0("test", 0);
84 // CHECK-MESSAGES: [[@LINE-1]]:20: warning: constructor creating an empty string
85 std::string_view q1(kText, -4);
86 // CHECK-MESSAGES: [[@LINE-1]]:20: warning: negative value used as length parameter
87 std::string_view q2("test", 200);
88 // CHECK-MESSAGES: [[@LINE-1]]:20: warning: length is bigger than string literal size
89 std::string_view q3(kText, 200);
90 // CHECK-MESSAGES: [[@LINE-1]]:20: warning: length is bigger than string literal size
91 std::string_view q4(kText2, 200);
92 // CHECK-MESSAGES: [[@LINE-1]]:20: warning: length is bigger than string literal size
93 std::string_view q5(kText3, 0x1000000);
94 // CHECK-MESSAGES: [[@LINE-1]]:20: warning: suspicious large length parameter
95 std::string_view q6(nullptr);
96 // CHECK-MESSAGES: [[@LINE-1]]:20: warning: constructing string from nullptr is undefined behaviour
97 std::string_view q7 = 0;
98 // CHECK-MESSAGES: [[@LINE-1]]:25: warning: constructing string from nullptr is undefined behaviour
99}
100
101void TestUnsignedArguments() {
102 std::string s0("test", 0u);
103 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: constructor creating an empty string
104 std::string s1(0x1000000ull, 'x');
105 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: suspicious large length parameter
106 std::string s2("test", 3ull, 2u);
107 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: length is bigger than remaining string literal size
108 std::string s3("test", 0u, 5ll);
109 // CHECK-MESSAGES: [[@LINE-1]]:15: warning: length is bigger than string literal size
110}
111
112std::string StringFromZero() {
113 return 0;
114 // CHECK-MESSAGES: [[@LINE-1]]:10: warning: constructing string from nullptr is undefined behaviour
115}
116
117std::string_view StringViewFromZero() {
118 return 0;
119 // CHECK-MESSAGES: [[@LINE-1]]:10: warning: constructing string from nullptr is undefined behaviour
120}
121
122void Valid() {
123 std::string empty();
124 std::string str(4, 'x');
125 std::wstring wstr(4, L'x');
126 std::string s1("test", 4);
127 std::string s2("test", 3);
128 std::string s3("test");
129 std::string s4("test\000", 5);
130 std::string s6("te" "st", 4);
131 std::string s7("test", 0, 4);
132 std::string s8("test", 3, 1);
133 std::string s9("te" "st", 1, 2);
134
135 std::string_view emptyv();
136 std::string_view sv1("test", 4);
137 std::string_view sv2("test", 3);
138 std::string_view sv3("test");
139}
140
141namespace instantiation_dependent_exprs {
142template<typename T>
143struct S {
144 bool x;
145 std::string f() { return x ? "a" : "b"; }
146 std::string_view g() { return x ? "a" : "b"; }
147};
148}
149

source code of clang-tools-extra/test/clang-tidy/checkers/bugprone/string-constructor.cpp