"I/O exception during sandboxed execution" "Directory not empty" with --experimental_reuse_sandbox_directories #19935
Description
Description of the bug:
--experimental_reuse_sandbox_directories can produce non-hermetic behavior when attempting to reuse a sandbox stash that contains a directory where a file is needed.
Which category does this issue belong to?
Core
What's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.
Minimal example: https://github.com/jfirebaugh/bazel_experimental_reuse_sandbox_directories_bug
Clone this repository, and run bazel build --repo_env=CREATE_DIRECTORY=1 --experimental_reuse_sandbox_directories genrule followed by bazel build --repo_env=CREATE_DIRECTORY=0 --experimental_reuse_sandbox_directories genrule (the only difference between the two is the CREATE_DIRECTORY value). The second command will fail with:
ERROR: <workspace>/BUILD.bazel:1:8: Executing genrule //:genrule failed: I/O exception during sandboxed execution: <output_base>/sandbox/darwin-sandbox/18/execroot/__main__/external/repository/output (Directory not empty)
If the second command is modified to remove the use of --experimental_reuse_sandbox_directories, then it succeeds. It also succeeds if you delete the sandbox stash (rm -rf "$(bazel info output_base)/sandbox/sandbox_stash").
Which operating system are you running Bazel on?
macOS
What is the output of bazel info release?
release 6.4.0
If bazel info release returns development version or (@non-git), tell us how you built Bazel.
No response
What's the output of git remote get-url origin; git rev-parse master; git rev-parse HEAD ?
n/a
Is this a regression? If yes, please try to identify the Bazel commit where the bug was introduced.
No
Have you found anything relevant by searching the web?
No
Any other information, logs, or outputs that you want to share?
No response