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fix corner case in conditionals (#3809)

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fixes #3808
This commit is contained in:
Alex Lam S.L
2020-04-21 23:30:08 +01:00
committed by GitHub
parent 925a0ca1a0
commit 9577c8c1b7
2 changed files with 52 additions and 6 deletions
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24
lib/compress.js
View File

@@ -4933,9 +4933,21 @@ merge(Compressor.prototype, {
}); });
def(AST_Sequence, function(compressor, first_in_statement) { def(AST_Sequence, function(compressor, first_in_statement) {
var expressions = trim(this.expressions, compressor, first_in_statement); var expressions = trim(this.expressions, compressor, first_in_statement);
if (expressions === this.expressions) return this;
if (!expressions) return null; if (!expressions) return null;
return make_sequence(this, expressions); var end = expressions.length - 1;
var assign, cond, lhs;
if (compressor.option("conditionals")
&& end > 0
&& (assign = expressions[end - 1]) instanceof AST_Assign
&& assign.operator == "="
&& (lhs = assign.left) instanceof AST_SymbolRef
&& (cond = to_conditional_assignment(compressor, lhs.definition(), assign.right, expressions[end]))) {
assign = assign.clone();
assign.right = cond;
expressions = expressions.slice(0, -2);
expressions.push(assign);
}
return expressions === this.expressions ? this : make_sequence(this, expressions);
}); });
def(AST_Sub, function(compressor, first_in_statement) { def(AST_Sub, function(compressor, first_in_statement) {
if (this.expression.may_throw_on_access(compressor)) return this; if (this.expression.may_throw_on_access(compressor)) return this;
@@ -6390,16 +6402,16 @@ merge(Compressor.prototype, {
function merge_conditional_assignments() { function merge_conditional_assignments() {
if (!compressor.option("conditionals")) return; if (!compressor.option("conditionals")) return;
for (var i = 0; i < end; i++) { for (var i = 1; i < end; i++) {
var assign = expressions[i]; var assign = expressions[i - 1];
if (!(assign instanceof AST_Assign)) continue; if (!(assign instanceof AST_Assign)) continue;
if (assign.operator != "=") continue; if (assign.operator != "=") continue;
if (!(assign.left instanceof AST_SymbolRef)) continue; if (!(assign.left instanceof AST_SymbolRef)) continue;
var def = assign.left.definition(); var def = assign.left.definition();
var cond = to_conditional_assignment(compressor, def, assign.right, expressions[i + 1]); var cond = to_conditional_assignment(compressor, def, assign.right, expressions[i]);
if (!cond) continue; if (!cond) continue;
assign.right = cond; assign.right = cond;
expressions.splice(i + 1, 1); expressions.splice(i, 1);
end--; end--;
} }
} }

34
test/compress/conditionals.js
View File

@@ -1759,3 +1759,37 @@ conditional_assignments_3: {
} }
expect_stdout: "PASS" expect_stdout: "PASS"
} }
issue_3808_1: {
options = {
conditionals: true,
side_effects: true,
}
input: {
var a;
a = "PASS", [] + "" && (a = "FAIL");
console.log(a);
}
expect: {
var a;
a = [] + "" ? "FAIL" : "PASS";
console.log(a);
}
expect_stdout: "PASS"
}
issue_3808_2: {
options = {
conditionals: true,
side_effects: true,
}
input: {
var a;
console.log((a = "PASS", [] + "" && (a = "FAIL")), a);
}
expect: {
var a;
console.log((a = "PASS", [] + "" && (a = "FAIL")), a);
}
expect_stdout: " PASS"
}