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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /js/src/tests/non262/Function/configurable-length.js | |
parent | Initial commit. (diff) | |
download | firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | js/src/tests/non262/Function/configurable-length.js | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/js/src/tests/non262/Function/configurable-length.js b/js/src/tests/non262/Function/configurable-length.js new file mode 100644 index 0000000000..127038fb56 --- /dev/null +++ b/js/src/tests/non262/Function/configurable-length.js @@ -0,0 +1,86 @@ +/* Any copyright is dedicated to the Public Domain. + * http://creativecommons.org/licenses/publicdomain/ */ + +// Very simple initial test that the "length" property of a function is +// configurable. More thorough tests follow. +var f = function (a1, a2, a3, a4) {}; +assertEq(delete f.length, true); +assertEq(f.hasOwnProperty("length"), false); +assertEq(f.length, 0); // inherited from Function.prototype.length +assertEq(delete Function.prototype.length, true); +assertEq(f.length, undefined); + + +// Now for the details. +// +// Many of these tests are poking at the "resolve hook" mechanism SM uses to +// lazily create this property, which is wonky and deserving of some extra +// skepticism. + +// We've deleted Function.prototype.length. Check that the resolve hook does +// not resurrect it. +assertEq("length" in Function.prototype, false); +Function.prototype.length = 7; +assertEq(Function.prototype.length, 7); +delete Function.prototype.length; +assertEq(Function.prototype.length, undefined); + +// OK, define Function.prototype.length back to its original state per spec, so +// the remaining tests can run in a more typical environment. +Object.defineProperty(Function.prototype, "length", {value: 0, configurable: true}); + +// Check the property descriptor of a function length property. +var g = function f(a1, a2, a3, a4, a5) {}; +var desc = Object.getOwnPropertyDescriptor(g, "length"); +assertEq(desc.configurable, true); +assertEq(desc.enumerable, false); +assertEq(desc.writable, false); +assertEq(desc.value, 5); + +// After deleting the length property, assigning to f.length fails because +// Function.prototype.length is non-writable. In strict mode it would throw. +delete g.length; +g.length = 12; +assertEq(g.hasOwnProperty("length"), false); +assertEq(g.length, 0); + +// After deleting both the length property and Function.prototype.length, +// assigning to f.length creates a new plain old data property. +delete Function.prototype.length; +g.length = 13; +var desc = Object.getOwnPropertyDescriptor(g, "length"); +assertEq(desc.configurable, true); +assertEq(desc.enumerable, true); +assertEq(desc.writable, true); +assertEq(desc.value, 13); + +// Deleting the .length of one instance of a FunctionDeclaration does not +// affect other instances. +function mkfun() { + function fun(a1, a2, a3, a4, a5) {} + return fun; +} +g = mkfun(); +var h = mkfun(); +delete h.length; +assertEq(g.length, 5); +assertEq(mkfun().length, 5); + +// Object.defineProperty on a brand-new function is sufficient to cause the +// LENGTH_RESOLVED flag to be set. +g = mkfun(); +Object.defineProperty(g, "length", {value: 0}); +assertEq(delete g.length, true); +assertEq(g.hasOwnProperty("length"), false); + +// Object.defineProperty on a brand-new function correctly merges new +// attributes with the builtin ones. +g = mkfun(); +Object.defineProperty(g, "length", { value: 42 }); +desc = Object.getOwnPropertyDescriptor(g, "length"); +assertEq(desc.configurable, true); +assertEq(desc.enumerable, false); +assertEq(desc.writable, false); +assertEq(desc.value, 42); + +reportCompare(0, 0, 'ok'); |