Hi Steve, thanks for sharing this problem.

NCrunch has had this problem come up a few times in its history. I had hoped that we'd seen the last of it, but I guess that's not the case!

Is this a problem that you're seeing often or can reproduce at will?

The first thing we need to do is figure out where the desync is happening. This could be in the instrumentation, the engine, or the UI.

When the problem appears, does closing and re-opening the code window resolve it?

Hi Steve,

Can you identify any pattern around what causes it? Does it happen very often?

If you're running the new build (v3.17), it would be really interesting if you could submit a bug report after it happens. The report might yield some clues as to what is going on.

Note that the bug reporter in v3.16 and earlier versions won't work as they don't contain the 'GDPR Checkbox'.

Hi,

Just FYI, the problem has gone away since updating to the latest version. For now anyway.

Thanks,

Steve.

Ok, will do.

Thanks,

Steve.

Thanks Steve. The report confirms that this isn't the result of a tragic and obvious malfunction, which is somewhat disappointing as it means this will be very hard to find.

I'll try to share with you the information I have on this problem in the hope that it might help you to narrow down what is causing it on your side.

- The problem happens as a result of an internal desync between the actual code positions and NCrunch's code coverage index
- It is not a visual/UI based issue, which means that this is happening in the engine itself
- It is not likely to be the downstream result of a separate issue (no exceptions appearing in the logs)
- It's been at least a couple of years since we last had a known and reported issue in this area
- The code responsible hasn't been touched for a year or more
- This leads me to believe there is something unique about your solution or environment that is surfacing the issue
- Previously, I have observed this issue appearing with tiny projects that have an unexpectedly fast build time. This was due to MSBuild's filestamp-checking cache system preventing the compiler from working correctly on rapidly repeated builds

Are you running any other 3rd party tools inside your IDE? Is there a particular project that seems to be singled out by this problem? Are you using distributed processing?

I think that this problem may be related to an optimisation in MSBuild, where it doesn't update files unless they have a timestamp mismatched with the file being updated. I've seen this happen before when using high-end hardware on tiny projects with older versions of MSBuild (i.e. 2008, 2010), because the system runs the build so quickly that two different builds executed in sequence don't have enough of a gap for the timestamp to be separated, so the files don't get copied and the source code falls out of sync with the binaries.

This is all theory at this stage, because such a situation is so hard to reproduce that there isn't likely to be a way that I can confirm that it's happening for you. To be honest, it's been years since I've seen it happen.

However, if it IS the problem, then likely it will go away on it's own as you continue to add code to your project. All you need is the tiniest increase in your build time, and you'll never see it again.

There is a known issue where CodeLens changes the vertical size of some lines of code (notably the first line of constructors). This causes the NCrunch markers to look a bit out of place on these lines, as they are aligned with the top of the line rather than the bottom.

I've had a bit of a brainwave today and I think I may have found a way to fix this by aligning the markers to the bottom of the line instead. I'd like to dogfood this for a while before releasing it in case it breaks VS somehow, but I'm hoping that you'll see this out with the next version of NCrunch.

This will almost certainly be something else, though probably it will likewise be hard to pin down and fix.

When you see this, would you mind submitting a bug report for me? The log may yield some clues as to what's happening here.

Does the problem disappear when you close and reopen the code window affected by it?

Also, do you have any third party VS extensions installed other than NCrunch?

I'm having trouble reproducing this issue. The Codelens 'lines' are usually represented in the IDE as just being a vertical extension to an existing code line (i.e. the code line is just made bigger), so I'm concerned about how this seems to be happening on some systems.

Does this happen consistently for you? Does disabling codelens resolve it? Are you running any other 3rd party VS extensions that might affect VS code rendering?

Technically, scrolling the code up and down should cause the markers to be re-rendered, but this won't rebuild the marker gutter container. Closing and reopening the file is the only way to completely reset things.

Am I correct in my understanding that this is an intermittent issue for you?

If you have any luck in identifying what is special about these files and why it only happens for them, I'd really like to know. If I can reproduce the issue, maybe I can fix it for good :)

It's suspicious the way this has suddenly come up with a VS update. I wonder if it might be an internal issue inside VS itself. In which case it may even disappear on its own.