onEnterFrame-generator-02.js

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// onEnterFrame fires after the [[GeneratorState]] is set to "executing".

//

// This test checks that Debugger doesn't accidentally make it possible to

// reenter a generator frame that's already on the stack. (Also tests a fun

// corner case in baseline debug-mode OSR.)

load(libdir + "asserts.js");

let g = newGlobal({newCompartment: true});

g.eval('function* f() { yield 1; yield 2; }');

let dbg = Debugger(g);

let genObj = null;

let hits = 0;

dbg.onEnterFrame = frame => {

    // The first time onEnterFrame fires, there is no generator object, so

    // there's nothing to test. The generator object doesn't exist until

    // JSOP_GENERATOR is reached, right before the initial yield.

    if (genObj !== null) {

        dbg.removeDebuggee(g);  // avoid the DebuggeeWouldRun exception

        assertThrowsInstanceOf(() => genObj.next(), g.TypeError);

        dbg.addDebuggee(g);

        hits++;

};

genObj = g.f();

for (let x of genObj) {}

assertEq(hits, 3);