Showing differences from Visual Studio sometimes opens 2 copies of BC4

[azzwin83]

I have BC4 setup as my custom command for viewing differences for files in VS2013 using TFS.

My configuration is like this:

Extension: .*
Operation: Compare
Command: C:\Program Files (x86)\Beyond Compare 4\BComp.exe
Arguments: %1 %2 /title1=%6 /title2=%7

If I view my Pending Changes, then right-click a file and "Compare with Workspace Version", it normally opens up correctly in BC4, all good. But once in a while the operation might take 5sec or so, and when that happens there will appear 2 separate instances of BC4.

BTW this used to happen for me last year, in VS2008 on BC3 too but I failed to report it, oops

This could be a nightmare to reproduce, I don't know the circumstances which it happens. Seems completely random and I can never replicate it on purpose. Is there anything I can do to help you guys find and fix this?

Thanks
Azz

[Aaron]

Hello,

That is an odd one. You are selecting a single file, then attempting the command to launch a diff. When you get two instances of BC4:
1) In process explorer, are there multiple bcompare.exe processes running or just one? A 'new instance' of BC4 can share the same process, unless the /solo command line parameter is used, even when using the Desktop shortcut.
2) What information is within the windows? Are they blank/home screens? Or do they show your files?

[azzwin83]

1) I will check that the next time it happens.
2) They show my files correctly. Each window has the before file on the left and the current file on the right.

I take it you haven't seen this before

Is there some logging I can switch on maybe?

[Aaron]

I do not think we have a logging switch for this scenario, but you could use Process Explorer to see if there's any variance to how it was called twice, or the System or Applications log in the Windows Event Viewer.

[azzwin83]

OK I think I have a way of reliably reproducing it now. Sometimes I'll open up a new instance of BC for comparing stuff from the clipboard, I'll then paste a chunk of text into each pane, and use BC to check for differences. Separately I'll instantiate BC from Visual Studio and the comparison then appears twice.

So it seems that the steps are like this:
0. ensure there are no BComp or BCompare instances in task manager
1. open up a new instance of BC by clicking on the icon in my taskbar. (It opens up automatically in text compare mode, with 2 empty panes)
2. switch to Visual Studio, right click a modified file and click Compare. (the comparison opens up as a New Tab in the existing instance, AND then about 5sec later a New Window appears, also with the same comparison.)

If I look at ProcExp I can see this:

|_ explorer.exe
.....|
.....|_ devenv.exe
.....|.....|_ BComp.exe
.....|..........|_ BCompare.exe
.....|
.....|_ BCompare.exe

Hope this helps you reproduce it
Thanks

[tgilbert]

I also experience the double Beyond Compare processes when comparing files except I am using Visual Studio 2010 with TFS and Beyond Compare 3. I seem to get it very consistently.

[Chris]

I tried reproducing this with Visual Studio 2013 and Team Foundation Server 2012. I tested BC 3.3.10 and BC 4 beta build 18291, but I haven't been able to repeat the problem. Every time I've launched a compare, only one tab or window was opened. The behavior is the same if BC is not open or if I already have a BC window open with clipboard contents.

For anyone still experiencing this problem:

What are the exact versions of Visual Studio, TFS, and Beyond Compare that you are running?

What are the steps that open Beyond Compare twice with a single Compare command in Visual Studio?

[azzwin83]

I can reproduce it every time now. Maybe the main difference is that the 1st BC instance needs to be opened separately.

1. Click on BC icon in the Win7 taskbar, to open a brand new instance of BC. It shows an empty left side and an empty right side.

2. Open VS, open the Pending Changes window, find a file that has some changes.

3. Right-click on the changed file and select Compare With Workspace Version. The file is added as a new tab in the existing BC instance.

4. Wait 3-4 secs. Another new instance of BC appears with the selected file in it.

I'm on VS2013 SP2 Professional (12.0.30501.00 Update 2) and BC4 beta (build 18291).

Thanks

[Chris]

azzwin83,

Thank you for the follow up. I'm still unable to duplicate this on my test system. Please send a copy of your Beyond Compare settings to [email protected] and I'll continue trying to duplicate the problem.

To save your settings to a file, select "Help > Support" and click the Export button.

Also, please include a link to this forum thread in your email.

[Chris]

I just repeated this problem and our lead developer implemented a fix that will be in the next release of Beyond Compare 4.

When you already have BC open and you launch a new comparison from version control, a new instance of BC is launched. If it detects BC is already running, the comparison is passed to the existing instance unless it is hung. The hang detection timeout is 5 seconds.

This bug is repeatable if the existing instance of Beyond Compare is running with standard user rights and a diff is launched from Visual Studio launched using "Run As Administrator".

[azzwin83]

Confirmed fixed. Thanks!