1 // RUN: %check_clang_tidy %s readability-redundant-string-init %t \
2 // RUN:   -config="{CheckOptions: \
3 // RUN:             [{key: readability-redundant-string-init.StringNames, \
4 // RUN:               value: '::std::basic_string;::std::basic_string_view;our::TestString'}] \
5 // RUN:             }"
6 
7 namespace std {
8 template <typename T>
9 class allocator {};
10 template <typename T>
11 class char_traits {};
12 template <typename C, typename T = std::char_traits<C>, typename A = std::allocator<C>>
13 struct basic_string {
14   basic_string();
15   basic_string(const basic_string&);
16   basic_string(const C *, const A &a = A());
17   ~basic_string();
18 };
19 typedef basic_string<char> string;
20 typedef basic_string<wchar_t> wstring;
21 
22 template <typename C, typename T = std::char_traits<C>, typename A = std::allocator<C>>
23 struct basic_string_view {
24   using size_type = decltype(sizeof(0));
25 
26   basic_string_view();
27   basic_string_view(const basic_string_view &);
28   basic_string_view(const C *, size_type);
29   basic_string_view(const C *);
30   template <class It, class End>
31   basic_string_view(It, End);
32 };
33 typedef basic_string_view<char> string_view;
34 typedef basic_string_view<wchar_t> wstring_view;
35 }
36 
f()37 void f() {
38   std::string a = "";
39   // CHECK-MESSAGES: [[@LINE-1]]:15: warning: redundant string initialization [readability-redundant-string-init]
40   // CHECK-FIXES: std::string a;
41   std::string b("");
42   // CHECK-MESSAGES: [[@LINE-1]]:15: warning: redundant string initialization
43   // CHECK-FIXES: std::string b;
44   std::string c = R"()";
45   // CHECK-MESSAGES: [[@LINE-1]]:15: warning: redundant string initialization
46   // CHECK-FIXES: std::string c;
47   std::string d(R"()");
48   // CHECK-MESSAGES: [[@LINE-1]]:15: warning: redundant string initialization
49   // CHECK-FIXES: std::string d;
50   std::string e{""};
51   // CHECK-MESSAGES: [[@LINE-1]]:15: warning: redundant string initialization
52   // CHECK-FIXES: std::string e;
53   std::string f = {""};
54   // CHECK-MESSAGES: [[@LINE-1]]:15: warning: redundant string initialization
55   // CHECK-FIXES: std::string f;
56 
57   std::string u = "u";
58   std::string w("w");
59   std::string x = R"(x)";
60   std::string y(R"(y)");
61   std::string z;
62 }
63 
fview()64 void fview() {
65   std::string_view a = "";
66   // CHECK-MESSAGES: [[@LINE-1]]:20: warning: redundant string initialization [readability-redundant-string-init]
67   // CHECK-FIXES: std::string_view a;
68   std::string_view b("");
69   // CHECK-MESSAGES: [[@LINE-1]]:20: warning: redundant string initialization
70   // CHECK-FIXES: std::string_view b;
71   std::string_view c = R"()";
72   // CHECK-MESSAGES: [[@LINE-1]]:20: warning: redundant string initialization
73   // CHECK-FIXES: std::string_view c;
74   std::string_view d(R"()");
75   // CHECK-MESSAGES: [[@LINE-1]]:20: warning: redundant string initialization
76   // CHECK-FIXES: std::string_view d;
77   std::string_view e{""};
78   // CHECK-MESSAGES: [[@LINE-1]]:20: warning: redundant string initialization
79   // CHECK-FIXES: std::string_view e;
80   std::string_view f = {""};
81   // CHECK-MESSAGES: [[@LINE-1]]:20: warning: redundant string initialization
82   // CHECK-FIXES: std::string_view f;
83 
84   std::string_view u = "u";
85   std::string_view w("w");
86   std::string_view x = R"(x)";
87   std::string_view y(R"(y)");
88   std::string_view z;
89 }
90 
g()91 void g() {
92   std::wstring a = L"";
93   // CHECK-MESSAGES: [[@LINE-1]]:16: warning: redundant string initialization
94   // CHECK-FIXES: std::wstring a;
95   std::wstring b(L"");
96   // CHECK-MESSAGES: [[@LINE-1]]:16: warning: redundant string initialization
97   // CHECK-FIXES: std::wstring b;
98   std::wstring c = LR"()";
99   // CHECK-MESSAGES: [[@LINE-1]]:16: warning: redundant string initialization
100   // CHECK-FIXES: std::wstring c;
101   std::wstring d(LR"()");
102   // CHECK-MESSAGES: [[@LINE-1]]:16: warning: redundant string initialization
103   // CHECK-FIXES: std::wstring d;
104 
105   std::wstring u = L"u";
106   std::wstring w(L"w");
107   std::wstring x = LR"(x)";
108   std::wstring y(LR"(y)");
109   std::wstring z;
110 }
111 
gview()112 void gview() {
113   std::wstring_view a = L"";
114   // CHECK-MESSAGES: [[@LINE-1]]:21: warning: redundant string initialization [readability-redundant-string-init]
115   // CHECK-FIXES: std::wstring_view a;
116   std::wstring_view b(L"");
117   // CHECK-MESSAGES: [[@LINE-1]]:21: warning: redundant string initialization
118   // CHECK-FIXES: std::wstring_view b;
119   std::wstring_view c = L"";
120   // CHECK-MESSAGES: [[@LINE-1]]:21: warning: redundant string initialization
121   // CHECK-FIXES: std::wstring_view c;
122   std::wstring_view d(L"");
123   // CHECK-MESSAGES: [[@LINE-1]]:21: warning: redundant string initialization
124   // CHECK-FIXES: std::wstring_view d;
125   std::wstring_view e{L""};
126   // CHECK-MESSAGES: [[@LINE-1]]:21: warning: redundant string initialization
127   // CHECK-FIXES: std::wstring_view e;
128   std::wstring_view f = {L""};
129   // CHECK-MESSAGES: [[@LINE-1]]:21: warning: redundant string initialization
130   // CHECK-FIXES: std::wstring_view f;
131 
132   std::wstring_view u = L"u";
133   std::wstring_view w(L"w");
134   std::wstring_view x = LR"(x)";
135   std::wstring_view y(LR"(y)");
136   std::wstring_view z;
137 }
138 
139 template <typename T>
templ()140 void templ() {
141   std::string s = "";
142   // CHECK-MESSAGES: [[@LINE-1]]:15: warning: redundant string initialization
143   // CHECK-FIXES: std::string s;
144 }
145 
146 #define M(x) x
147 #define N { std::string s = ""; }
148 // CHECK-FIXES: #define N { std::string s = ""; }
149 
h()150 void h() {
151   templ<int>();
152   templ<double>();
153 
154   M({ std::string s = ""; })
155   // CHECK-MESSAGES: [[@LINE-1]]:19: warning: redundant string initialization
156   // CHECK-FIXES: M({ std::string s; })
157 
158   N
159   // CHECK-MESSAGES: [[@LINE-1]]:3: warning: redundant string initialization
160   // CHECK-FIXES: N
161   N
162   // CHECK-MESSAGES: [[@LINE-1]]:3: warning: redundant string initialization
163   // CHECK-FIXES: N
164 }
165 
166 typedef std::string MyString;
167 #define STRING MyString
168 #define DECL_STRING(name, val) STRING name = val
169 
i()170 void i() {
171   MyString a = "";
172   // CHECK-MESSAGES: [[@LINE-1]]:12: warning: redundant string initialization
173   // CHECK-FIXES: MyString a;
174   STRING b = "";
175   // CHECK-MESSAGES: [[@LINE-1]]:10: warning: redundant string initialization
176   // CHECK-FIXES: STRING b;
177   MyString c = "" "" "";
178   // CHECK-MESSAGES: [[@LINE-1]]:12: warning: redundant string initialization
179   // CHECK-FIXES: MyString c;
180   STRING d = "" "" "";
181   // CHECK-MESSAGES: [[@LINE-1]]:10: warning: redundant string initialization
182   // CHECK-FIXES: STRING d;
183   DECL_STRING(e, "");
184   // CHECK-MESSAGES: [[@LINE-1]]:15: warning: redundant string initialization
185 
186   MyString f = "u";
187   STRING g = "u";
188   DECL_STRING(h, "u");
189 }
190 
191 #define EMPTY_STR ""
j()192 void j() {
193   std::string a(EMPTY_STR);
194   // CHECK-MESSAGES: [[@LINE-1]]:15: warning: redundant string initialization
195   // CHECK-FIXES: std::string a;
196   std::string b = (EMPTY_STR);
197   // CHECK-MESSAGES: [[@LINE-1]]:15: warning: redundant string initialization
198   // CHECK-FIXES: std::string b;
199 
200   std::string c(EMPTY_STR "u" EMPTY_STR);
201 }
202 
k()203 void k() {
204   std::string a = "", b = "", c = "";
205   // CHECK-MESSAGES: [[@LINE-1]]:15: warning: redundant string initialization
206   // CHECK-MESSAGES: [[@LINE-2]]:23: warning: redundant string initialization
207   // CHECK-MESSAGES: [[@LINE-3]]:31: warning: redundant string initialization
208   // CHECK-FIXES: std::string a, b, c;
209 
210   std::string d = "u", e = "u", f = "u";
211 
212   std::string g = "u", h = "", i = "uuu", j = "", k;
213   // CHECK-MESSAGES: [[@LINE-1]]:24: warning: redundant string initialization
214   // CHECK-MESSAGES: [[@LINE-2]]:43: warning: redundant string initialization
215   // CHECK-FIXES: std::string g = "u", h, i = "uuu", j, k;
216 }
217 
218 // These cases should not generate warnings.
219 extern void Param1(std::string param = "");
220 extern void Param2(const std::string& param = "");
Param3(std::string param="")221 void Param3(std::string param = "") {}
Param4(STRING param="")222 void Param4(STRING param = "") {}
223 
224 namespace our {
225 struct TestString {
226   TestString();
227   TestString(const TestString &);
228   TestString(const char *);
229   ~TestString();
230 };
231 }
232 
ourTestStringTests()233 void ourTestStringTests() {
234   our::TestString a = "";
235   // CHECK-MESSAGES: [[@LINE-1]]:19: warning: redundant string initialization
236   // CHECK-FIXES: our::TestString a;
237   our::TestString b("");
238   // CHECK-MESSAGES: [[@LINE-1]]:19: warning: redundant string initialization
239   // CHECK-FIXES: our::TestString b;
240   our::TestString c = R"()";
241   // CHECK-MESSAGES: [[@LINE-1]]:19: warning: redundant string initialization
242   // CHECK-FIXES: our::TestString c;
243   our::TestString d(R"()");
244   // CHECK-MESSAGES: [[@LINE-1]]:19: warning: redundant string initialization
245   // CHECK-FIXES: our::TestString d;
246 
247   our::TestString u = "u";
248   our::TestString w("w");
249   our::TestString x = R"(x)";
250   our::TestString y(R"(y)");
251   our::TestString z;
252 }
253 
254 namespace their {
255 using TestString = our::TestString;
256 }
257 
258 // their::TestString is the same type so should warn / fix
theirTestStringTests()259 void theirTestStringTests() {
260   their::TestString a = "";
261   // CHECK-MESSAGES: [[@LINE-1]]:21: warning: redundant string initialization
262   // CHECK-FIXES: their::TestString a;
263   their::TestString b("");
264   // CHECK-MESSAGES: [[@LINE-1]]:21: warning: redundant string initialization
265   // CHECK-FIXES: their::TestString b;
266 }
267 
268 namespace other {
269 // Identical declarations to above but different type
270 struct TestString {
271   TestString();
272   TestString(const TestString &);
273   TestString(const char *);
274   ~TestString();
275 };
276 
277 // Identical declarations to above but different type
278 template <typename T>
279 class allocator {};
280 template <typename T>
281 class char_traits {};
282 template <typename C, typename T = std::char_traits<C>, typename A = std::allocator<C>>
283 struct basic_string {
284   basic_string();
285   basic_string(const basic_string &);
286   basic_string(const C *, const A &a = A());
287   ~basic_string();
288 };
289 typedef basic_string<char> string;
290 typedef basic_string<wchar_t> wstring;
291 }
292 
293 // other::TestString, other::string, other::wstring are unrelated to the types
294 // being checked. No warnings / fixes should be produced for these types.
otherTestStringTests()295 void otherTestStringTests() {
296   other::TestString a = "";
297   other::TestString b("");
298   other::string c = "";
299   other::string d("");
300   other::wstring e = L"";
301   other::wstring f(L"");
302 }
303 
304 class Foo {
305   std::string A = "";
306   // CHECK-MESSAGES: [[@LINE-1]]:15: warning: redundant string initialization
307   // CHECK-FIXES:  std::string A;
308   std::string B;
309   std::string C;
310   std::string D;
311   std::string E = "NotEmpty";
312 
313 public:
314   // Check redundant constructor where Field has a redundant initializer.
Foo()315   Foo() : A("") {}
316   // CHECK-MESSAGES: [[@LINE-1]]:11: warning: redundant string initialization
317   // CHECK-FIXES:  Foo()  {}
318 
319   // Check redundant constructor where Field has no initializer.
Foo(char)320   Foo(char) : B("") {}
321   // CHECK-MESSAGES: [[@LINE-1]]:15: warning: redundant string initialization
322   // CHECK-FIXES:  Foo(char)  {}
323 
324   // Check redundant constructor where Field has a valid initializer.
Foo(long)325   Foo(long) : E("") {}
326   // CHECK-MESSAGES: [[@LINE-1]]:15: warning: redundant string initialization
327   // CHECK-FIXES:  Foo(long) : E() {}
328 
329   // Check how it handles removing 1 initializer, and defaulting the other.
Foo(int)330   Foo(int) : B(""), E("") {}
331   // CHECK-MESSAGES: [[@LINE-1]]:14: warning: redundant string initialization
332   // CHECK-MESSAGES: [[@LINE-2]]:21: warning: redundant string initialization
333   // CHECK-FIXES:  Foo(int) :  E() {}
334 
Foo(short)335   Foo(short) : B{""} {}
336   // CHECK-MESSAGES: [[@LINE-1]]:16: warning: redundant string initialization
337   // CHECK-FIXES:  Foo(short)  {}
338 
Foo(float)339   Foo(float) : A{""}, B{""} {}
340   // CHECK-MESSAGES: [[@LINE-1]]:16: warning: redundant string initialization
341   // CHECK-MESSAGES: [[@LINE-2]]:23: warning: redundant string initialization
342   // CHECK-FIXES:  Foo(float)  {}
343 
344   // Check how it handles removing some redundant initializers while leaving
345   // valid initializers intact.
Foo(std::string Arg)346   Foo(std::string Arg) : A(Arg), B(""), C("NonEmpty"), D(R"()"), E("") {}
347   // CHECK-MESSAGES: [[@LINE-1]]:34: warning: redundant string initialization
348   // CHECK-MESSAGES: [[@LINE-2]]:56: warning: redundant string initialization
349   // CHECK-MESSAGES: [[@LINE-3]]:66: warning: redundant string initialization
350   // CHECK-FIXES:  Foo(std::string Arg) : A(Arg),  C("NonEmpty"),  E() {}
351 };
352