Add flag to keep CWD in bazel run

[kerrick-lyft]

Feature request:

I would like to request a flag --keep_cwd be added to bazel run that, when set, runs the child process in the same working directory that bazel was invoked in.

In addition, I'd propose adding a BUILD_RUNFILES (or maybe just RUNFILES) environment variable that contains the runfiles path (this is the same as PWD when --keep_cwd is not passed). This way, binaries can be updated to be agnostic to whether --keep_cwd was passed or not by always looking under $BUILD_RUNFILES for runfiles instead of under the CWD.

This is similar to #3325 but I'm trying to put forward a concrete proposal that is backwards compatible.

Feature requests: what underlying problem are you trying to solve with this feature?

Oftentimes I would like to bazel run a program relative to the working directory (e.g. a program that dumps some output to a text file in the CWD).

If this option existed, I would probably add it to the .bazelrc in the repository that I work in (after double-checking that binaries correctly reference BUILD_RUNFILES instead of PWD) because running in the CWD is a very common use-case for me and other users of this repository (currently we use the work-around bazel build //path/to:bin && bazel-bin/path/to/bin).

What operating system are you running Bazel on?

macOS 10.15.4.

What's the output of bazel info release?

release 3.3.0-homebrew

What's the output of git remote get-url origin ; git rev-parse master ; git rev-parse HEAD ?

(proprietary repo)

Have you found anything relevant by searching the web?

#3325

https://stackoverflow.com/questions/47764221/how-to-write-files-to-current-directory-instead-of-bazel-out

Any other information, logs, or outputs that you want to share?

In #3325 they propose using argv[0] to get the directory that the binary was invoked in in order to infer the runfiles directory, but I'm not sure this is as simple or as general as just having a BUILD_RUNFILES env var.

I'm not hard set on the name --keep_cwd; it's just a suggestion.

[oquenchil]

See Jin's answer here: https://stackoverflow.com/a/47872013

This is not possible by design. I will close this issue.