Missing branch coverage in typescript async method

[RoniSegal]

I have the bellow method written in typescript and transpiled to es5:

.

The transpiled code is:

SchedulerController.prototype.pollOnce = function () {
        return __awaiter(this, void 0, void 0, function () {
            var logger, scheduledEvent, err_1;
            return __generator(this, function (_a) {
                switch (_a.label) {
                    case 0:
                        logger = this.logger.withMethod("pollOnce");
                        _a.label = 1;
                    case 1:
                        _a.trys.push([1, 5, , 6]);
                        return [4 /*yield*/, this.getNextScheduledEvent(logger)];
                    case 2:
                        scheduledEvent = _a.sent();
                        if (!scheduledEvent) return [3 /*break*/, 4];
                        return [4 /*yield*/, this.runJob(scheduledEvent)];
                    case 3:
                        _a.sent();
                        _a.label = 4;
                    case 4: return [3 /*break*/, 6];
                    case 5:
                        err_1 = _a.sent();
                        logger.error("Error in iteration", err_1);
                        return [3 /*break*/, 6];
                    case 6: return [2 /*return*/];
                }
            });
        });
    };

The source map data for

 if (!scheduledEvent) return [3 /*break*/, 4];

points to line 126

Expected Behavior

line 126 should considered as branch

Observed Behavior

line 126 considered as statement

[coreyfarrell]

From what you're showing this line should be considered both a branch if (!scheduledEvent) and a statement return [3 /*break*/, 4];. To triage this issue we will need to see a minimal reproduction. If you create a minimal demo repository showing the build / test process it will help us help you.

[RoniSegal]

I created a repo with reproduction: https://github.com/RoniSegal/missing-branch-coverage.
you can see that in file 'lib/scheduler-controller.ts' 0 branches reported, but actually it contains 4 'if' and 1 'else'

[RoniSegal]

Any updates on this?

[JaKXz]

@RoniSegal as Corey mentioned we need to see a minimal reproduction in a public repo. Then we can help investigate.

[coreyfarrell]

@JaKXz https://github.com/RoniSegal/missing-branch-coverage was provided - the link is easy to miss in @RoniSegal's comment from two days ago.

[RoniSegal]

@JaKXz sorry for that, I updated the comment and now its more clear

[RoniSegal]

There is an update on this issue?

[coreyfarrell]

@RoniSegal I just tried your repo:

git clone https://github.com/RoniSegal/missing-branch-coverage
cd missing-branch-coverage
npm install
npm test

Got the following error:

> nyc --reporter=html mocha tsOutputs/test

Warning: Could not find any test files matching pattern: tsOutputs/test
No test files found
npm ERR! Test failed.  See above for more details.

Please fix this error, once the test is working someone can take a look. Keep in mind this issue will require someone with knowledge of both istanbul and TypeScript, so it may take longer to get help. Any updates will be posted here.

One other suggestion, take a look at @istanbuljs/nyc-config-typescript.

[RoniSegal]

@coreyfarrell Just updated my repo, it missed npm run build.
Per the other suggestion I must use compiled code that may not use this config

[coreyfarrell]

I'm able to reproduce this issue now. I checked the the if (event === "failed") branch. tsc translated this to if (event == "failed") at line 70. In the raw coverage data I was able to see that we saw the branch at line 70, we recorded that the tests hit this branch. But then it was not displayed in the final report. I suspect this is showing that something went wrong with source-map remapping, so this is likely a bug in istanbul-lib-source-maps.

[RoniSegal]

@coreyfarrell thanks for looking into it, should i open a new issue and point it to istanbul-lib-source-map?

[RoniSegal]

@coreyfarrell Seems that istanbul-lib-source-maps is part of istanbuljs repo (under packages),
Is it still should be transfered?

[coreyfarrell]

@RoniSegal that is correct, I got mixed up for some reason thought this was reported against nyc.

[RoniSegal]

Any updates on this?
Thanks

[coreyfarrell]

@RoniSegal Sorry there is not, source maps issues are very difficult. If any updates are available they will be posted here.

[nadavye]

Hi Guys,
Any update on this one?