.git/index.lock can be held when vscode is in background because of GitLens calls to `git status`

[joelhock]

• gitlens|eam|5.5.0
• VSCode Version: Code 1.17.0 (be377c0faf7574a59f84940f593a6849f12e4de7, 2017-10-05T06:07:51.906Z)
• OS Version: Darwin x64 16.7.0

Steps to Reproduce:

1. switch from vscode to terminal (so that vscode is in the background)
2. touch file (or do something that touches files, like a git pull --rebase)
3. see that getStatusForRepo('/my/path/to/repo') is called in GitLens output channel
4. if operation in terminal needs .git/index.lock (e.g. a git rebase operation), it may fail, since the GitLens getStatusForRepo may be holding the lock.

vscode's grabbing of the .git/index.lock has been the source of a number of issues filed against it, the main one of which is microsoft/vscode#11918
other extensions are now being identified that do the same thing, such as:
letmaik/vscode-git-tree-compare#24

The behavior of GitLens can be sidestepped with gitlens.gitExplorer.includeWorkingTree": false, but I think GitLens should either not call git status when vscode is in the background via the mechanism introduced in microsoft/vscode@475fb0e, or it should instruct git (well, future versions of git) to not grab the lock during git status calls via the mechanism in microsoft/vscode#35513

[joelhock]

and now that I look at things a bit more, I see that GitLens will call getStatusForRepo in response to the git cache changing, so gitlens.gitExplorer.includeWorkingTree": false is not a complete workaround. the filesystem watch that it controls made the problem worse, so setting it to false can still help mitigate the issue.

[eamodio]

FYI -- I added the GIT_OPTIONAL_LOCKS=0 to GitLens 5.6, but I am currently blocked from adding the background checks by microsoft/vscode#36010

[joelhock]

thank you!!

[wmakley]

Happening to me constantly in Windows with WSL remote mode and the latest version of VSCode and Gitlens.

[eamodio]

@wmakley Please open a new issue for this and attach logs and a clear description of what you were doing and the error that happened. Thanks!