Avoid creating test runfile trees when using sandboxfs

[pauldraper]

Description of the problem / feature request:

Avoid creating test runfile trees when using sandboxfs.

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

The entire point of sandboxfs is avoiding creating symlinks.

But when running bazel test, the symlink tree is created anyway. This seems unnecessary, no?

[sgowroji]

Hello @pauldraper, Could you please provide more details with respect to your query. Thanks!

[pauldraper]

Even with sandboxfs being used, runfiles trees are still being created in the output root for builds, tests, etc.

[meisterT]

cc @larsrc-google

[larsrc-google]

Possibly related to issue #7470.

Could you show a command line that prompts this behaviour, and what you're seeing that you didn't expect? A couple of tries didn't get me to get sandboxfs to work for tests at all.

[pauldraper]

WORKSPACE.bazel

workspace(name = "example")

BUILD.bazel

sh_binary(
  name = "test",
  data = ["data.txt"],
  srcs = ["test.sh"],
)

test.sh

#!/bin/sh

data.txt

Run

bazel  test --experimental_use_sandboxfs :test

Notice that the symlink bazel-bin/test.runfiles/example/data.txt is created. If there are many tests or many files (scripting languages, external dependencies, end-to-end tests, etc), populating the runfile trees can be costly.

Sandboxfs (when enabled) could be used to avoid materializing the runfile tree.

[benjaminp]

217fafe

[tjgq]

FYI, we do have a flag to suppress the creation of runfile symlink trees (--nobuild_runfile_links). This is orthogonal to sandboxing, because the purpose of sandboxing is not to manage the output tree, but to create a hermetic environment separate from the output tree where an action can run.