1 // Copyright 2008 the V8 project authors. All rights reserved. 2 // Redistribution and use in source and binary forms, with or without 3 // modification, are permitted provided that the following conditions are 4 // met: 5 // 6 // * Redistributions of source code must retain the above copyright 7 // notice, this list of conditions and the following disclaimer. 8 // * Redistributions in binary form must reproduce the above 9 // copyright notice, this list of conditions and the following 10 // disclaimer in the documentation and/or other materials provided 11 // with the distribution. 12 // * Neither the name of Google Inc. nor the names of its 13 // contributors may be used to endorse or promote products derived 14 // from this software without specific prior written permission. 15 // 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 28 // Test for const semantics. 29 30 31 function CheckException(e) { 32 var string = e.toString(); 33 var index = string.indexOf(':'); 34 assertTrue(index >= 0); 35 var name = string.slice(0, index); 36 assertTrue(string.indexOf("has already been declared") >= 0 || 37 string.indexOf("redeclaration") >= 0); 38 if (name == 'SyntaxError') return 'TypeError'; 39 return name; 40 } 41 42 43 function TestLocal(s,e) { 44 try { 45 return eval("(function(){" + s + ";return " + e + "})")(); 46 } catch (x) { 47 return CheckException(x); 48 } 49 } 50 51 52 // NOTE: TestGlobal usually only tests the given string in the context 53 // of a global object in dictionary mode. This is because we use 54 // delete to get rid of any added properties. 55 function TestGlobal(s,e) { 56 // Collect the global properties before the call. 57 var properties = []; 58 for (var key in this) properties.push(key); 59 // Compute the result. 60 var result; 61 try { 62 var code = s + (e ? "; $$$result=" + e : ""); 63 if (this.execScript) { 64 execScript(code); 65 } else { 66 this.eval(code); 67 } 68 // Avoid issues if $$$result is not defined by 69 // reading it through this. 70 result = this.$$$result; 71 } catch (x) { 72 result = CheckException(x); 73 } 74 // Get rid of any introduced global properties before 75 // returning the result. 76 for (var key in this) { 77 if (properties.indexOf(key) == -1) delete this[key]; 78 } 79 return result; 80 } 81 82 83 function TestContext(s,e) { 84 try { 85 // Use a with-statement to force the system to do dynamic 86 // declarations of the introduced variables or constants. 87 with ({}) { 88 return eval(s + ";" + e); 89 } 90 } catch (x) { 91 return CheckException(x); 92 } 93 } 94 95 96 function TestAll(expected,s,opt_e) { 97 var e = ""; 98 var msg = s; 99 if (opt_e) { e = opt_e; msg += "; " + opt_e; } 100 assertEquals(expected, TestLocal(s,e), "local:'" + msg + "'"); 101 // Redeclarations of global consts do not throw, they are silently ignored. 102 assertEquals(42, TestGlobal(s, 42), "global:'" + msg + "'"); 103 assertEquals(expected, TestContext(s,e), "context:'" + msg + "'"); 104 } 105 106 107 function TestConflict(def0, def1) { 108 // No eval. 109 TestAll("TypeError", def0 +'; ' + def1); 110 // Eval everything. 111 TestAll("TypeError", 'eval("' + def0 + '; ' + def1 + '")'); 112 // Eval first definition. 113 TestAll("TypeError", 'eval("' + def0 +'"); ' + def1); 114 // Eval second definition. 115 TestAll("TypeError", def0 + '; eval("' + def1 + '")'); 116 // Eval both definitions separately. 117 TestAll("TypeError", 'eval("' + def0 +'"); eval("' + def1 + '")'); 118 } 119 120 121 // Test conflicting definitions. 122 TestConflict("const x", "var x"); 123 TestConflict("const x = 0", "var x"); 124 TestConflict("const x", "var x = 0"); 125 TestConflict("const x = 0", "var x = 0"); 126 127 TestConflict("var x", "const x"); 128 TestConflict("var x = 0", "const x"); 129 TestConflict("var x", "const x = 0"); 130 TestConflict("var x = 0", "const x = 0"); 131 132 TestConflict("const x = undefined", "var x"); 133 TestConflict("const x", "var x = undefined"); 134 TestConflict("const x = undefined", "var x = undefined"); 135 136 TestConflict("var x = undefined", "const x"); 137 TestConflict("var x", "const x = undefined"); 138 TestConflict("var x = undefined", "const x = undefined"); 139 140 TestConflict("const x = undefined", "var x = 0"); 141 TestConflict("const x = 0", "var x = undefined"); 142 143 TestConflict("var x = undefined", "const x = 0"); 144 TestConflict("var x = 0", "const x = undefined"); 145 146 TestConflict("const x", "function x() { }"); 147 TestConflict("const x = 0", "function x() { }"); 148 TestConflict("const x = undefined", "function x() { }"); 149 150 TestConflict("function x() { }", "const x"); 151 TestConflict("function x() { }", "const x = 0"); 152 TestConflict("function x() { }", "const x = undefined"); 153 154 TestConflict("const x, y", "var x"); 155 TestConflict("const x, y", "var y"); 156 TestConflict("const x = 0, y", "var x"); 157 TestConflict("const x = 0, y", "var y"); 158 TestConflict("const x, y = 0", "var x"); 159 TestConflict("const x, y = 0", "var y"); 160 TestConflict("const x = 0, y = 0", "var x"); 161 TestConflict("const x = 0, y = 0", "var y"); 162 163 TestConflict("var x", "const x, y"); 164 TestConflict("var y", "const x, y"); 165 TestConflict("var x", "const x = 0, y"); 166 TestConflict("var y", "const x = 0, y"); 167 TestConflict("var x", "const x, y = 0"); 168 TestConflict("var y", "const x, y = 0"); 169 TestConflict("var x", "const x = 0, y = 0"); 170 TestConflict("var y", "const x = 0, y = 0"); 171 172 173 // Test that multiple conflicts do not cause issues. 174 TestConflict("var x, y", "const x, y"); 175 176 177 // Test that repeated const declarations throw redeclaration errors. 178 TestConflict("const x", "const x"); 179 TestConflict("const x = 0", "const x"); 180 TestConflict("const x", "const x = 0"); 181 TestConflict("const x = 0", "const x = 0"); 182 183 TestConflict("const x = undefined", "const x"); 184 TestConflict("const x", "const x = undefined"); 185 TestConflict("const x = undefined", "const x = undefined"); 186 187 TestConflict("const x = undefined", "const x = 0"); 188 TestConflict("const x = 0", "const x = undefined"); 189 190 TestConflict("const x, y", "const x"); 191 TestConflict("const x, y", "const y"); 192 TestConflict("const x = 0, y", "const x"); 193 TestConflict("const x = 0, y", "const y"); 194 TestConflict("const x, y = 0", "const x"); 195 TestConflict("const x, y = 0", "const y"); 196 TestConflict("const x = 0, y = 0", "const x"); 197 TestConflict("const x = 0, y = 0", "const y"); 198 199 TestConflict("const x", "const x, y"); 200 TestConflict("const y", "const x, y"); 201 TestConflict("const x", "const x = 0, y"); 202 TestConflict("const y", "const x = 0, y"); 203 TestConflict("const x", "const x, y = 0"); 204 TestConflict("const y", "const x, y = 0"); 205 TestConflict("const x", "const x = 0, y = 0"); 206 TestConflict("const y", "const x = 0, y = 0"); 207 208 209 // Test that multiple const conflicts do not cause issues. 210 TestConflict("const x, y", "const x, y"); 211 212 213 // Test that const inside loop behaves correctly. 214 var loop = "for (var i = 0; i < 3; i++) { const x = i; }"; 215 TestAll(0, loop, "x"); 216 TestAll(0, "var a,b,c,d,e,f,g,h; " + loop, "x"); 217 218 219 // Test that const inside with behaves correctly. 220 TestAll(87, "with ({x:42}) { const x = 87; }", "x"); 221 TestAll(undefined, "with ({x:42}) { const x; }", "x"); 222 223 224 // Additional tests for how various combinations of re-declarations affect 225 // the values of the var/const in question. 226 try { 227 eval("var undefined;"); 228 } catch (ex) { 229 assertUnreachable("undefined (1) has thrown"); 230 } 231 232 var original_undef = undefined; 233 var undefined = 1; // Should be silently ignored. 234 assertEquals(original_undef, undefined, "undefined got overwritten"); 235 undefined = original_undef; 236 237 var a; const a; const a = 1; 238 assertEquals(1, a, "a has wrong value"); 239 a = 2; 240 assertEquals(2, a, "a should be writable"); 241 242 var b = 1; const b = 2; 243 assertEquals(2, b, "b has wrong value"); 244 245 var c = 1; const c = 2; const c = 3; 246 assertEquals(3, c, "c has wrong value"); 247 248 const d = 1; const d = 2; 249 assertEquals(1, d, "d has wrong value"); 250 251 const e = 1; var e = 2; 252 assertEquals(1, e, "e has wrong value"); 253 254 const f = 1; const f; 255 assertEquals(1, f, "f has wrong value"); 256 257 var g; const g = 1; 258 assertEquals(1, g, "g has wrong value"); 259 g = 2; 260 assertEquals(2, g, "g should be writable"); 261 262 const h; var h = 1; 263 assertEquals(undefined,h, "h has wrong value"); 264 265 eval("Object.defineProperty(this, 'i', { writable: true });" 266 + "const i = 7;" 267 + "assertEquals(7, i, \"i has wrong value\");"); 268 269 var global = this; 270 assertThrows(function() { 271 Object.defineProperty(global, 'j', { writable: true }) 272 }, TypeError); 273 const j = 2; // This is what makes the function above throw, because the 274 // const declaration gets hoisted and makes the property non-configurable. 275 assertEquals(2, j, "j has wrong value"); 276 277 var k = 1; const k; 278 // You could argue about the expected result here. For now, the winning 279 // argument is that "const k;" is equivalent to "const k = undefined;". 280 assertEquals(undefined, k, "k has wrong value"); 281
